Integration of Lean Con. and Building Information Modelling (0)

Ergo Pikas
Integration of Lean Construction and Building Information Modelling DISSERTATION
Tallinn 2010 2 UNIVERSITY OF APPLIED SCIENCES
Author : Ergo Pikas- Civil Engineering student , Faculty of Construction , Tallinn University of Applied Sciences Supervisor: Rafael Sacks- Associate Professor , Faculty of Civil and Env. Engineering, Technion ­ Israel Institute of Technology Consultant: Roode Liias- Professor and Dean , Faculty of Civil Engineering, Tallinn University of Technology Title: Integration of Lean Construction and Building Information Modelling Archived: University of Applied Sciences, Faculty of Construction
ABSTRACT
This research can be divided into two. The first part investigates the current state of the construction industry, while the second part looks at new emerging business models ­ in particular , Lean Construction (LC) and Building Information Modelling (BIM), as well as an integration of these two.
Given that the construction industry does not have a particularly good reputation among the public, the first part of this thesis focuses mainly on this problem and its sources . It is the reason why we need new and better business models, like LC and BIM, or even an integration of the two models.
Both LC and BIM have been shown to have a profound impact on improving construction processes and therefore , project outcomes, as discussed in the third and the fourth chapters. Different studies and practical experience show that a combination of these originally independent approaches can ensure even better processes. Integrated Project Delivery (IPD), which is discussed in the fifth chapter , is an example of this. In conclusion , a recommendation supported by research is made for improving the Estonian construction industrys performance .
Key words : Lean Construction (LC), Building Information Modelling (BIM), Integrated Project Delivery (IPD), Design- Build (DB), Design-Bid-Build (DBB), etc. (see also 1.4).
3 TABLE OF CONTENTS
ABSTRACT .............................................................................................................................................3
CHAPTER 1- INTRODUCTION ..........................................................................................................7
1.1 PROBLEM FORMULATION ..................................................................................................................7 1.2 RESEARCH METHODOLOGY ...............................................................................................................8 1.3 RESEARCH STRUCTURE .....................................................................................................................9 1.4 ABBREVIATIONS ...............................................................................................................................9
CHAPTER 2- PROBLEMS IN THE CONSTRUCTION INDUSTRY ...........................................10
2.1 PROBLEMS ......................................................................................................................................10 2.2 CAUSES OF THE PROBLEMS .............................................................................................................12 2.2.1 Structural: contractual systems ...............................................................................................12 2.2.2 Management in construction ...................................................................................................15 2.2.21 Conventional production management theory in construction..........................................16 2.2.22 Conventional project management theory in construction ................................................17 2.2.23 Learning and improvement ...............................................................................................19 2.2.3 Lack of technological exploitation ..........................................................................................19 2.3 EMPIRICAL STUDIES: SUMMARY OF RESEARCH CONDUCTED AMONG THE MAIN CONTRACTING COMPANIES IN ESTONIA ........................................................................................................................20
2.3.1 Research summary ..................................................................................................................21 2.4 CONCLUSION ..................................................................................................................................24
CHAPTER 3- LEAN CONSTRUCTION ...........................................................................................26
3.1 REQUIREMENTS FOR A PRODUCTION SYSTEM ..................................................................................27 3.2 THE TOYOTA PRODUCTION SYSTEM (TPS) .....................................................................................30 3.3 PHILOSOPHY OF LEAN CONSTRUCTION ...........................................................................................34 3.3.1 TFV views as the foundation for Lean Construction ..............................................................35 3.3.11 Value in construction projects ...........................................................................................36 3.3.12 Flow in construction ..........................................................................................................38
4 3.3.13 Waste identification in construction ..................................................................................40 3.3.2 The Lean Construction principles driven by the TFV model .................................................42 3.3.3 Management theory in construction........................................................................................44 3.3.31 Predictability in flow and processes (LPSTM) ...................................................................45 3.3.311 Levels of the Last Planner System ..............................................................................46 3.3.4 Discussion ...............................................................................................................................49 3.4 CONCLUSION ..................................................................................................................................49
CHAPTER 4- BUILDING INFORMATION MODELLING ...........................................................50
4.1 DEFINITION OF BIM: PARAMETRIC MODELLING ..............................................................................50 4.1.1 What BIM is not......................................................................................................................51 4.2 INTEROPERABILITY .........................................................................................................................51 4.3 IMPLEMENTATION OF BIM ..............................................................................................................52 4.3.11 Collaboration.........................................................................................................................52 4.3.12 Planning use of BIM .............................................................................................................53 4.3.13 BIM functionalities/uses .......................................................................................................55 4.4 CONCLUSION ..................................................................................................................................58
CHAPTER 5- INTEGRATION OF LEAN CONSTRUCTION AND BUILDING INFORMATION MODELLING .........................................................................................................59
5.1 THEORETICAL WORK OF INTEGRATING LEAN CONSTRUCTION AND BUILDING INFORMATION MODELLING ..........................................................................................................................................59 5.2. INTEGRATED PROJECT DELIVERY (IPD) ........................................................................................60 5.2.1 Definition of IPD ....................................................................................................................61 5.2.2Principles of IPD ......................................................................................................................62 5.2.3 Organization, operating system and commercial terms ..........................................................64 5.2.31 Project organization...........................................................................................................64 5.2.32 Operating system ...............................................................................................................66 5.2.33 Commercial terms .............................................................................................................68 5.2.4 Legal relationships ..................................................................................................................68 5.2.5 Discussion ...............................................................................................................................69 5.3 EMPIRICAL EVIDENCE FOR LC AND BIM SYNERGY.........................................................................69
5 5.3.1 Crusell Bridge case study ........................................................................................................69 5.3.2 Discussion ...............................................................................................................................71 5.4 CONCLUSION ..................................................................................................................................73
CHAPTER 6- CONCLUSION .............................................................................................................74
6.1 ANSWERS TO QUESTIONS ................................................................................................................74 6.3 SOLUTION FOR ESTONIAN CONSTRUCTION INDUSTRY .....................................................................77 6.4 ACKNOWLEDGMENT .......................................................................................................................77 6.5 SUMMARY IN ESTONIAN .................................................................................................................78 6.6 BIBLIOGRAPHY ...............................................................................................................................93
APPENDIX 1: CRUSELL BRIDGE CASE STUDY .........................................................................97
6 CHAPTER 1- INTRODUCTION
Over time the Architecture , Engineering, and Construction (AEC) industry has become more complex and demanding . Clients are no longer expecting only to meet schedule , cost and quality objectives but also to guarantee safety , human satisfaction and minimal negative environmental impact (Vanegas, DuBose and Pearce 1996). Traditional construction project delivery methods and models have failed to satisfy the expectations of both contractors and clients. The main problems and their causes are analysed in the second chapter of this thesis. Thus people in the AEC industry, including scholars and practitioners, have come together to find new solutions for delivering projects and fulfilling high requirements.
1.1 Problem formulation
The construction industry makes up a great share of the Gross Domestic Product (GDP) in many countries all over the world and provides employment to a great number of people. Thus, it is important to conduct research in this field , with a view to making it more productive, safe and free of waste. This can all happen only with a better understanding of the concepts, principles and physics of the construction industry. Therefore, many academics , academic institutions and even companies have started to work together to propose solutions for the problems occurring in the construction industry.
LC and BIM are fundamentally different approaches and ordinarily implemented independently. Their great positive impact on the industry in general has been noted by a variety of parties . Moreover , there are also significant attempts to combine these two models to achieve even better project outcomes, as in the case of IPD.
7 For the Estonian construction industry these are fairly new models. Thus the following questions drive the present research in its goal of gaining a better understanding of these new business models:
1. What are the main problems connected with the construction industry and what are their causes? 2. Which problems have been arising in the Estonian construction industry? 3. What is LC: the concept , its principles and tools ? 4. What is BIM: the concept, the process and its functionalities? 5. Can LC and BIM be integrated and what are the results ? 6. What is IPD? 7. Are LC and BIM applicable to the Estonian construction industry?
1.2 Research methodology
At the highest level, the present research can be divided into the following two functions : literature review and empirical study.
Literature review. This is based on available publications, articles and white papers from the International Group for Lean Construction, etc. (see also Bibliography).
Empirical study. This is based on the following three sources: first, the Crusell Bridge 1case study ( included in the appendices), which provided examples ; second, research whose objective was to determine the current state of the Estonian construction industry (see also chapter 2); and finally , information gathered from visiting Estonian and Finish construction companies and discussions with different parties from Estonia, Finland and England .
1 The Author of this thesis in collaboration with his supervisor Sacks R. conducted an empirical field study and prepared the Crusell Bridge cases study as a part of the second edition of the BIM Handbook (see also appendix 1.).
8 1.3 Research structure
Chapter 2 investigates the main problems connected with the construction industry worldwide and the causes of these problems. In particular, it is investigated if these problems apply to the Estonian construction industry using a summary of the research compiled by the author of this thesis.
Chapter 3 investigates LC, its concept, principles and the tools that make it possible to address the problems raised in the second chapter.
Chapter 4 discusses what BIM is and what is needed for its implementation.
Chapter 5 investigates the question of whether a synergy exists between these two models analysed in the second and third chapter and the question of what form it would take. Afterwards, one particular example of the integration of LC and BIM, the IPD model, is discussed. This is supported by the Crusell Bridge case study and a discussion of the authors ideas .
Chapter 6, conclusions are drawn and the questions outlined in chapter 1 are answered.
1.4 Abbreviations
4D- 3D CAD + time IPD- Integrated Project Delivery 5D- 4D CAD + money LC- Lean Construction AEC- Architecture, Engineering, Construction LPDS - Lean Project Delivery System BIM- Building Information Modelling LPS- Last Planner System CII- Construction Industry Institute NVA- Non-Value Adding CPM- Critical -Path Method NVAR- Non-Value Adding activities but Required DB- Design-Build PPC- Percent Plan Completed DBB- Design-Bid-Build TFV- Transformation-Flow-Value EstGLC- Estonian Group for Lean Construction TPS- Toyota Production System GC- General Contractor VDC- Virtual Design & Construction IGLC- International Group for Lean Construction 5Whys- Root causes analysing technique
9 CHAPTER 2- PROBLEMS IN THE CONSTRUCTION INDUSTRY
In the second chapter of this thesis, the main problems and their causes are discussed. It is done by analysing the literature, previous research in this field, and the results of empirical research conducted among the main contracting companies in Estonia. Basically, the aim is to understand the reasons for the failures at the root level.
2.1 Problems
Many studies of the problems and causes for the problems mostly point out the same issues associated with construction industry. The nature of the construction industry is very often characterized as the following (Koskela2 1992):
Low productivity Poor safety Inferior working conditions Insufficient quality
The construction industry is seen as an unproductive production system if compared with other industries, e.g., car manufacturing (Koskela and Vrijhoef 2001; Winch 1998). High levels of waste and unpredictability in terms of delivery, time, budget , profitability and standards of quality combine to
2 Professor, School of the Built Environment, University of Salford, Salford, UK. One of the founders of IGLC. Suggested TFV theory in 2000 as his PhD thesies.
10 give the construction industry one of the worst public images among the industrial sectors ( Egan 1998; Koskela 2000; Santos 1999).
The Centre for Integrated Facility Engineering, headed by Paul Teicholz at Stanford University, conducted research on labour productivity in the construction industry. The productivity of the construction industry in the US was studied in comparison with all non- farm industries over a period of forty years , from 1964 to 2003, as shown in the following figure .
Figure 1.1 Labour productivity index for US construction industry and all non-farm industries from 1964 through 2003, source Teicholz 2003.
Figure 1.1 shows that the construction industrys productivity has declined over the last four decades, while the productivity of non-farm industries has more than doubled . This means that more work per one dollar needs to be carried out in 2004 than needed to be carried out in 1960 to achieve the same results. The problem of stagnant productivity has been seen to be associated with the slow adoption of new and improved business practices and technologies.
Construction has also been seen as a wasteful process. The Construction Industry Institute (CII) in co- operation with the Lean Construction Institute (2004) have estimated that there is up to 57% of non- value adding (NVA) effort or waste in our current business models, but in manufacturing the percentage is only 12%. Waste (in Japanese " Muda ") is an activity that absorbs resources but adds no
11 value. The cause of this is seen to be related to poor organizational management: the design of the production system, communication and cooperation , and production planning and control .
Another study performed by the National Institute of Standards and Technology found that inefficient interoperability between different parties and systems often prevents members of the project team from sharing information rapidly and accurately (Gallaher 2004). Thus, the lack of accurate information and its slow exchange is one of the main reasons for the construction industrys low productivity, while availability of information is critical in the project-based construction industry for decision making.
In conclusion, we can say that there are plenty of problems, and therefore, it is necessary to study the causes of inefficiencies and to determine which of these causes has the greatest negative impact on performance.
2.2 Causes of the problems
Many causes for the problems start from client due to reason that client is not a professional. Too much attention is put on price than quality; i.e. contractors (all different specialty contractors) are chosen by the lowest bid. Also poor briefing and definition of the requirements for the project needs and functionalities result in the late changes of the design. It is due to the lack of systematic understanding of construction projects. Not only but also contractors unprofessionalism and incompetent commitment to the project are also issues that cause many problems.
2.2.1 Structural: contractual systems
Over time, facilities have become more complex, demanding and variable, resulting in the need to use specialty contractors, now accepted practice . Thus, to manage project-based construction processes, the two most prevalent contracting systems, Design-Build (DB) and Design-Bid-Build (DBB), were developed (see also figure 2.2).
12 Figure 2.2 DBB and DB model, source Guyer 2005.
Of course , there are more ways to structure the project delivery process but the ones mentioned above are most commonly used. Each has its own advantages and disadvantages , but in general, the main problem connected with these two models is that they divide the project delivery process into fragmented stages, where a sense of the whole is lost . Thus it is very often the case that a designer develops a product that is very complicated and expensive to construct. Inconsistency, inaccuracy, and uncertainty in design make it difficult to fabricate materials offsite, and the fact is that most construction work must be carried out on site, where working conditions are more unpredictable than in a factory. Working on site instead of in a factory is conducive to ineffective work, resulting in rework, working slowly and inventing work, thus leading to cost and time overruns. It creates the brick wall effect : the results of preceding stages will be thrown over the wall into the hands of other project parties, and this causes a loss of information and competence. However , the flow of accurate information in project-based delivery systems (the construction industry) is crucial for successful project outcomes.
In general (this applies to both contracting approaches), if a contractor has made a bid under the actual estimated price, what frequently happens is that the contractor abuses the change process, relying on error- and omission-ridden design documentation. For example, the contractor uses cheaper and lower quality materials, which very often leads to friction and disputes between the owner and the project team.
13 In the first chapter of the "BIM Handbook" (Eastman, Teicholz, Sacks, Liston 2008), the authors gave a critical assessment of existing DB and DBB contractual models and finally proposed the kind of model which would best support the implementation of BIM.
The two major benefits of the DBB model are competitive bidding to achieve the lowest possible price and less political pressure when selecting a given contractor, while the benefits of using DB are the fact that the responsibility for design and construction is consolidated into a single contracting entity and the simplification of the administration of tasks for the owner ( Beard et al. 2005). These benefits aside, there are disadvantages connected with DBB and DB as well, as shown in the figure below .
Design-Build versus Design-Bid-Build: Advantages and disadvantages Advantages Disadvantages Design-Build (stipulated price) Building is fully defined Limited assurance of quality control Agency may avoid disputes and conflicts Subjective contract award Builder involved in design process Limited access for small contractors Faster project delivery Agency needs less stuff
Design-Bid-Build Building is fully defined Agency gets involved in conflicts and disputes Competitive bidding results in lower price Builder not involved in design phase Relative ease assuring the quality control Price not certain until construction price is received Objective contract award Agency may need more technical stuff Good access for small contractors
Table 2.1 Advantages and disadvantages of DBB and DB model, source Guyer 2005.
In the DBB model, the client has separate contracts with the designer and general contractor (GC). Traditionally, the client also has a different contract with technical consultancy, whose work is to represent the client on site in matters related to different technical/technological issues. Contractors are usually chosen by the lowest bid, tempting them to optimize their activities by reducing the resources needed to deliver the project; consequently, this often leads to sub-optimal results. As GC's are chosen by the lowest bid, they use the Dutch auction to select sub-contractors, and this in turn encourages sub-
14 contractors to rig and cover their costs and reduce resources being spent on a project. Bids are quite frequently under the actual estimated price, and so understandably, it is in the interest of contractors to optimize activities they execute to stay within a limited budget. This, of course, is the opposite of what the client is expecting. This leads to conflicts, errors, and omissions in the project documentation, which in turn leads to waste of time (idled labour, equipment , etc.) and money in the construction phase.
According to the DB model, the client directly contracts with the DB team to develop a well-defined building program and a schematic design. After that, the DB team estimates the total cost and time needed to carry out the construction work. The good thing with this model is that modifications can be made in the early phase of design, reducing the money and time spent on doing it. After the cost and time required are settled on by the client and DB contractor, from this point on, the contractor basically gets full control over the project, giving the client less flexibility. For the client this results in limited assurance of quality control and limited access to sub-contractors.
2.2.2 Management in construction
Production management in construction, according to the present view, is divided into two main theories: production theory and management theory. In LC, production theory consists of three different sub-theories. This is the Transformation-Flow-Value (TFV) model defined by Koskela (2000), where the sub-theories are integrated together in purpose to accomplish a comprehensive theory of production (see chapter 2). Traditional management only focuses on the transformation view, as described below. At the same time, management theory consists of sub-concepts for ,,planning, ,,execution and ,,control of a production system. Koskela and Howell (2004) argue that the practice of construction management suffers from the three following shortcomings:
The role of planning is not logically defined, and short- term planning is normally poorly carried out or simply neglected. Execution is not managed efficiently. In other words, action is taken on tasks pushed by the plan without considering real conditions, as higher level plans are translated into short-term plans and then into action.
15 Control is too narrowly seen as measuring and taking corrective action, rather than as a process of learning.
Probably, decades ago, these traditional theories adequately satisfied requirements for the delivery of projects, but as society rapidly developed and over time, along with the construction industry became more complex and dynamic , the time arrived for a more comprehensive theory. LC is seen as one option for tackling these vast developments and changes, while it offers a coherent philosophy behind principles and methodologies.
2.2.21 Conventional production management theory in construction
The conventional production system in construction is based on the "Transformation" concept of production, and it has dominated most of the 20th century . Basically, a production system in construction should meet the three following criteria (Koskela and Ballard 2003): delivery of the product, minimizing of waste, and maximizing of value. The current view only satisfies the first one ­ delivery of the product. This model views production as the transformation of inputs into outputs (conversion activity), where an economically efficient process is achieved by improving each task independently, at the same time neglecting organizational management. A project is usually divided into smaller manageable chunks (e.g., tasks/activities) by using the work breakdown structuring method, which afterwards can be measured and analysed for planning. For each sub-process, the required resources are allocated without considering the current status of the production system; i.e., production is only focused on value adding activities (VAA) (see also chapter 3). As a lot of research has shown, this does not lead to more productive production. It is not the point speed that is important but rather the general throughput. The next figure illustrates the general idea of the transformation model:
16 Figure 1.3 Basic idea of conventional management, source Koskela 2000.
Many researchers point out the lack of a specific theory for construction. At the same time, a bad implementation of the few existing theories has been the root cause of construction industry underperformance and insufficiency (Koskela & Howell, 2002). Consequently, an explicit theory is the crucial and single most important issue for the future of the project management profession (Koskela and Howell 2002). Production in construction can and should be seen as a flow (Santos 1999).
2.2.22 Conventional project management theory in construction
Conventional project management tries to manage projects by scheduling (mainly by applying the critical-path method (CPM)), cost, and output. The CPM method was developed by DuPONT and Remington Rand around 1957. It was developed to mathematically calculate the sequence of activities in order to complete a project within the minimum time possible. CPM programs show activity dependencies and duration allocated for each activity. It also allows calculating the float of an activity, where float is the amount of time for how long a non-critical activity can be delayed without affecting the overall program. Today , the majority of construction companies use CPM as the main project management, planning and controlling mechanism, and it has been the main method over the last 4-5 decades. The main problem with CPM is that it does not consider other prerequisites beyond the preceding task, and it pushes work on instead of pulling work to completion. Of course, there are also other existing management methods, for example, line of balance , which was originally developed by the Goodyear Co. in the early 1940s and was further developed by the US Navy in the early 1950's for programming and control of both repetitive and non-repetitive projects (Turban 1968; Lutz and Halpin 1992). Here we focus on CPM because it is the most common method used in Estonia and other countries as well.
17 Management is primarily focused on organizational structuring and the creation of work breakdown structures . This leads construction into a situation where peculiarities appear, causing variability in production operations and a dismissal of the improvement process.
Scheduling means that activities are put into logical sequence to understand when each task should start, and the work of managers is to start the tasks as early as possible, in many cases leading to overproduction (a type of waste ­ see also chapter 3), and this in turn leads to uncertainty and unpredictability. Tasks are put under someones (a sub-contractors) responsibility through contracts. But breaking down activities into smaller ones, the basic idea of conventional management, makes the links between tasks weaker. The release of works form one crew to another one is assumed, and the result is an even more unpredictable workflow.
Of course, we can not claim that the conventionally accepted philosophy is not trying to deliver the value generated during the design phase. This is definitely the aim at the beginning of the project, but very often it is not achievable using existing management techniques, which push for early decisions and local optimization. The sources of that are usually risks that are shifted onto sub-contractors through contractual obligations, and the goals of the main contractor goals are unclear. So they are attempting to optimize their activities, and this leads to sub-optimal outcomes for the project, and these usually do not agree with general project goals. This is the opposite of what the main contractor managers are trying to achieve, namely, the best value and results for the customer.
Control operation, based on thermostat theory, is to monitor if a project is within cost and time limits . Action is taken only when delays in work appear. The techniques used to improve the situation often consist of speeding up sub-contractors, bringing in additional workers or re-sequencing jobs so that more important ones are finished first. Thus, managers are busy fixing the tasks that were not delivered on time, and this leaves them less time for planning upcoming tasks. This leads to the following project results: low productivity, poor safety, inferior working conditions, and insufficient quality.
Winch has stated the following causes for poor project management more succinctly, but they are basically the same as discussed above:
18 Table 2.2 The causes of problems in managing construction projects, source Winch 2009.
2.2.23 Learning and improvement
As a project-based environment, construction project delivery is a complex and dynamic process which makes continuous learning critical to the improvement of processes and therefore to the successful delivery of the project within time and budget limits. Conventional management techniques and processes lack the metrics that help to measure the productivity of construction work and fail to understand the causes of the failures. Last Planner System (LPS), invented by Ballard and Howell in 1992, adds a control component , Percent Plan Completed (PPC), to the traditional project management system to measure productivity. It is about learning from your own failures on a weekly or even daily basis and by doing it you can improve your production system (see also chapter 3).
2.2.3 Lack of technological exploitation
Implementing new technologies in the construction industry is seen as one possibility to improve the construction industrys productivity. Other industry sectors have already done it and adopted many new technological innovations, and because of this they have witnessed a great rise in efficiency and productivity. This is probably due to the peculiarities of the construction industry: one-of-a-kind
19 projects (basically the production of prototypes); site production (production units move through the product, unlike the case in manufacturing, where the product moves through assembly units on the shop floor); and temporary organization. But these peculiarities can be mitigated or eliminated altogether.
One of the main problems connected with the construction industry is that paper -based (2D) drawings are used for information exchange and constructing. Paper-based modes are prone to errors and omissions due to the reason that the drawings are created by hand and by many different parties. This often causes unanticipated field costs, delays, frictions, and eventual lawsuits between the different parties involved. A common problem associated with 2D paper-based documentation is that considerable time is needed to generate critical assessment of a proposed design in terms of cost, energy-efficiency, structures, etc. Often, these analyses are carried out at the last minute during the design process or even in the construction phase, when making changes is more expensive.
BIM (see also chapter 4) is seen as one solution for improvement. In recent years, more and more, companies have started to use applications that support the BIM model in place of applications that are based on 2D. Using BIM enhances the need for collaborative team work, speeds-up information exchange, and makes it more transparent and accurate. Still , it must be understood that BIM is effective only when implemented properly. Doing it the wrong way can result in greater waste (implementing BIM demands a great amount of initial funding) than is currently the case in the construction industry.
2.3 Empirical studies: Summary of research conducted among the main contracting companies in Estonia
The non- profit organization Estonian Group for Lean Construction (EstGLC 3), established May 20, 2009, and the author of this thesis conducted research among the 11 biggest Estonian GCs to determine the principle problems, their causes, and their consequences . For this study, the author of this thesis created an interactive survey in a web-based environment at the following address:
3 Estonian Group for Lean Construction (EstGLC) establised 20. May of 2009, member of IGLC and European Group for Lean Construction, further information: www.etet.ee
20 http://www.survsoft.com/esurv.php?s=26518&k=11074-0-25885 . Approximately 150 people were questioned and we received 78 acceptable answers. This summary is based on the following report "Ehitusprojektijuhtimise olukord aastal 2009" compiled by Ergo Pikas and EstGLC (if interested in the report, please contact the author of this thesis).
2.3.1 Research summary
64,75 % out of 379 projects were private orders , and another 35,25 % were public orders. Of these, 53,5 % were built according to the DBB contracting model, while another 38,5 % followed the DB contracting model. The remaining 8 % were other kinds of models. Thus the DBB contractual model is the most used model in the Estonian construction industry. It is probably due to the fact that Estonian clients and investors pay too much attention to price rather than quality. They also tend to fail to consider other fundamental values that a construction project ought to satisfy. As discussed in the earlier subchapters, the DBB approach is the most fragmented project delivery structure. Consequently, all the associated problems and their causes named in previous subchapters apply to the construction industry in Estonia.
We tried to determine the main applications that site crew members use daily. The figure below illustrates that site crews use mostly traditional applications that have been in use on sites over many decades. Thus a failure to exploit new information and communication tools in Estonia can also be seen as one of the main causes of problems. It is surprising if one considers that Estonian society is committed to being a leading edge information society. 60 % of contractors use Microsoft Project for daily work (scheduling tasks), while this model is based on CPM. Thus the prevailing problems (discussed previously) related to this management method also apply to the Estonian construction industry.
Research also revealed that Estonian site crews do not use applications that support the BIM model. Therefore, it is possible that partial improvement in the near future can come through involving BIM in management for construction projects. The Crusell Bridge case study shows that improvements in management are possible by employing BIM (see also sub-chapter 5.3.1 and appendix).
21 Figure 1.4 Most commonly used applications on site, Ergo (2009)
The size of the site crew differs corresponding to the complexity and cost of the project. Basically, this means that the more expensive and complex a project is, the more team members will be involved in temporary organization. Building a team where trust , respect and synergy between each other are present is an essential when striving for a better project.
GC's size of site crew according to the project price 30 Size of crew
20 10 0 1-20 milj 20-50 milj 50-100 milj 100-500 milj 500-1000 milj 1000-.... milj
Figure 1.5 Site crew size according to the project budget, Ergo (2009). Milj- means in English million.
Problems that were revealed in the first part of this chapter apply to the Estonian construction industry as well. Answers to the question, "What are the main aspects that cause problems on site?", were incomplete project documentation at 18 % and errors and omissions in the projects at 12 %. This is proof that fragmented project structure causes a lot of problems at the construction stage. Contrary to
22 this, many organizations and companies all over the world are already practicing integrated models, where pains and gains are shared through collegial agreements. Doing so, they have reduced expenses and time to deliver the project by up to 30 % (see also http://www.ipd-ca.net/ ).
Table 2.4 The main problems arising during project delivery, Ergo (2009)
What idles work, labour and equipment on site were also investigated. Mainly the same options as in previous table were given to respondents. The main problem here is related to poor planning, at 14 %. Current management methods (CPM, Line of Balance, Critical Chain , etc.) are not sufficient in satisfying all seven prerequisites or resource flows that must be fulfilled to execute the task (see also sub-chapter 3.3.12). In second place, errors and omissions in a project, at 13%, also cause idleness on site. However incorporating changes and corrections in a design during the construction stage is frequently a complicated, time consuming activity and expensive for the owner.
23 Figure 1.6 The main problems that idle work and labour on site, Ergo (2009).
This research revealed that the causes for counterproductive and insufficient project delivery are poor short-term planning and inadequate project documentation. The Estonian construction industry does not differ much from the construction industries of other countries. It has similar problems, and this is why it should be possible to learn from the experiences of other countries. The author of this thesis believes that these problems can be mitigated or eliminated by tackling the root causes, using new business models, in this case, LC and BIM.
2.4 Conclusion
"The 6th annual survey of construction owners" by CMAA4 (2005) has stated it very succinctly: The biggest cost impacting construction today is that of inefficiencies built into the way projects are run and managed ­ not costs of raw materials like steel and concrete, or the cost of labour.
The author of this thesis argues that the current theory of construction is inadequate and is the main cause for the construction industrys lack of productivity and insufficiency. Current theory is based on Transformation theory, instead of TFV, as suggested by Koskela in 2000, and does not give an explicit understanding of construction and what is needed to successfully deliver projects (see also chapter 3).
4 CMAA- Construction Management Association of America, www: www.cmaanet.org/
24 The general idea of current management theory is that projects consist of many separate and independent stages and activities, where economic efficiency will be achieved by improving each of these stages or activities independently. Thus, it neglects the systematic understanding of construction, i.e., where all the processes and stages in project delivery are coherent and influence each other to a greater or lesser degree.
Such an understanding of construction has given birth to the currently existing and mostly commonly used contractual models: DBB and DB. These tend to fragment project delivery, resulting in the loss of information and competence among experts at different stages. It creates the silo effect, where experts in different phases do their work and then throw it over the wall into the hands of other experts. Thus, it creates the effect that experts must recover the information they got from the previous project stages. This causes a double handling of information, where information due to human error can be lost. If you also consider unprofessionalism and incompetent commitment to a project, together with the fact, as revealed by the cited research, contracting companies are not open to new technological innovations, then the outcomes of the project will not be as expected by any of the parties involved. Finally, the consequences are facilities which are not energy-efficient (70-80% of energy use is defined during schematic design), are not constructible, have incomplete project documentation (error- and omission-ridden), and show poor short-term planning. The last two consequences have been statistically demonstrated by the author of this thesis. The problems and their associated causes revealed in the literature review apply to the Estonian construction industry, as demonstrated by the research summary, even if we take into account a difference in cultural backgrounds.
25 CHAPTER 3- LEAN CONSTRUCTION
Problems and constraints related to conventional production management, as discussed in the previous chapter, all lead to unproductive and inefficient project delivery. As a consequence, the construction industrys reputation among the public is not the best. At the same time, the productivity of other industries has risen multiple times over the last century, e.g., that of Toyota Motors Company, which has developed its own production system, known as Toyota Production System (TPS).
As many researchers have confirmed, the existing production system in construction lacks explicit theory and is underperforming. A group of enthusiasts established the International Group for Lean Construction in 1993 with the aim of bringing innovation and improvement to the construction industry. After nearly ten years of study, Lauri Koskela recommended in his Doctoral thesis a TFV model of production ­ integration of three different production models. All these models existed in the 20th century separately, and each of them was considered a different part of TFV theory, but when integrated together, the result is a more explicit and comprehensive theory of production. We can say that the starting point for him was TPS, but over time Lauri Koskela and other academics in this field have pulled in various other theories. The next figure is a simplified illustration of the previous statement :
Figure 3.1 TPS as the cornerstone for LC, adapted Lauri Koskela presentation from "First TTK Day of Project Management", 2009 November.
26 In succeeding sections, we will try to determine the requirements that a production system ought to fulfil. After that, we take a brief look at TPS, and this will be followed a consideration of the TFV and LC models. Finally, LPS5 , one of the most powerful tools for enhancing flow in construction, is discussed.
3.1 Requirements for a production system
Science in the matter of production theory has the two following goals (Koskela 2000): explanation (or understanding) of production and prediction of the future. Basically, what this means is that theory should allow us to foretell upcoming events in the system under consideration, and to understand the interactions between units and processes. All processes in production involving human action and organizational management are in a coherent system; understanding these patterns is essential for future improvements. This requires an understanding of the metaphysical nature of reality and with the use of empirical studies and evaluation of their validity . This is a circle of science where academics learn from reality and then try to put the observed into theory and then apply theory back to practice. It is a continuous never ending process.
Koskela claims in his research, which is based on a thorough literature study, that production theory consists of three levels, as shown in the next figure:
Figure 3.2 Practical methodologies are based on concepts and principles, source Koskela 2000.
5 Last Planner System is a registered trade mark of the Lean Construction Institute www.leanconstruction.org.
27 The highest level of the pyramid answers the question: "What is a production system?" It states the goals and requirements of a production system. Considering the TFV model proposed by Koskela, a production system in construction should fulfil the following three goals:
delivery of the product minimization of waste maximization of value
The second level is heuristics, common ways to contribute to the production system goals and to understand the relations between the concepts. These are the requirements for how methodologies/ actions /techniques must contribute to the production system goals, involving an understanding of how actions relate to goals. As the two upper levels involve the notion of concept, then these must be converted to reality through methods, techniques, functions and etc. ( Henrich , Bertelsen, Koskela, Kraemer, Rooke, and Owen, 2006).
On the most general level, there are three possible actions or functionalities in construction projects: design of the production system, control of it in order to realize the production intended, and improvement of the production system (Henrich, Bertelsen, Koskela, Kraemer, Rooke, and Owen, 2006). These functionalities should be understood as a coherent system, where design of the production system must be structured as simply as possible to deliver all the expected values and make reducing waste from the processes and operations feasible. It means design should facilitate (i.e., make transparent) operations and improvement. Operations should provide empirical data about the production system to the improvement action (e.g. PPC, see subchapter 3.5.1). Finally, improvement should address both operation and design of the system with relevant information for improvements.
Figure 3.3 Three main actions in construction projects, source Lauri Koskelas presentation at "First TTK Day of Project Management" November 2009.
28 Simply said, a production system in construction should be built up in a way that it gives decision- makers (managers) the information needed: the level of resource utilization, and controllable elements /parameters (metrics). It means a production system should supply managers with elements to manage work in matters of quality, speed, dependability, flexibility and cost. This is needed to deliver work on time and to ensure minimal work in progress, short customer lead times, and maximum utilization of resources. However, in-depth analyses of these goals show that they are in conflict. For example, it is easier to finish work on time if resource utilization is low. Thus, it is necessary to balance these goals.
It is definitely not as simple as it sounds. Because construction is a dynamic and complex system, its peculiarities make it difficult to design a production system in a simple way. According to Koskela and Ballard (2003), these peculiarities cause high variability. Therefore, peculiarities must be eliminated or mitigated first hand (see table 3.1 below).
Peculiarity Problems Solution One-of-a-kind production Almost every project is as a Pre-engineered delivering prototype products ; integration of different phases Site production External uncertainties; task Use prefabricated elements interdependencies Temporary organization Optimization of activities Long-term alliances; team (lowest bid); unreliable building from the exchange of information really point of beginning Table 3.1 Peculiarities of construction, source Koskela & Ballard 2003.
Now that we have outlined the requirements that a production system ought to satisfy, we can go forward with the TPS system, which is briefly discussed to make it clear why it has been so successful over the last decades. After that follows a discussion of TFV and LC.
29 3.2 The Toyota Production System (TPS)
TPS or just Lean manufacturing is a management philosophy for how to organize and manage the production processes. TPS was developed by the Japanese car manufacturer Toyota between 1948 and 1975. It was created by a group of engineers led by Taiichi Ohno6. He was a smart though difficult person dedicated to eliminating waste.
As the situation after WW II was economically complicated, Ohno understood that it was essential to treat a production system as a whole and to make it flexible. He took over Henry Fords work and continued to develop flow-based production management according to his own understanding. The result was one- piece flows. He also understood that the scheduling of work should not be driven by sales and production targets, but by actual sales. This created the need for " pull " system.
Engineer Ohno saw waste in every step of the conventional production system. If conventional production management is about producing as many cars as possible in the shortest feasible time (which is exactly the case in mass production), then Ohnos system is about making perfect cars (by decentralizing the decision making process, Jidoka7) in a flexible way and in the shortest time with nothing in inventory . It means that work stops if there are no orders from customers. The most difficult problem involved supplying production with the necessary bulk materials. In particular, it made planning and organizing the production system very important.
As he became aware of waste reduction in production, he understood that decisions made in the design phase affect cost and the sophistication of the execution phase. Thus he started to standardize design by considering all the limits that other stages of the production system are setting .
Taiichi Ohno, founder of TPS, expressed it in 1988 even more succinctly (Liker, 2003): "All we are doing is looking at the time line from the moment the customer gives us an order to the point when we collect the cash . And we are reducing that time line by removing the non-value-added wastes."
6 Toyotas executive , invented Toyota Production System between 1948 and 1975. 7 Sakichi Toyoda invented the principle of "intelligent automation" or "automation with a human touch ". Decentralizing decision making.
30 TPS is a sophisticated system of production, where all parties concerned must contribute to the whole. It encourages people to continually improve and learn the processes they work on and make it last in any business, which is the real challenge of TPS. The Toyota Way is based on five core values that all workers from top management down to regular operators are expected to follow and live by in their day to day work (Bicheno J. and Holweg M. 2009):
1. Challenge ­ to maintain a long-term vision and strive to meet all changes with the courage and creativity needed to realize that vision. 2. Kaizen ­ to strive for continuous improvement. There is always room for improvement, perfection does not exist . 3. Genchi Genbutshu ­ go see the problem, in other words, go to the source of problem. This is the belief that practical experience is valued over theoretical knowledge . You must see the problem to understand it. 4. Respect ­ to make every effort to understand others , accept responsibility and build mutual trust (introvert and extrovert). 5. Teamwork ­ to share opportunities for development and maximize team and individual performance.
Values drive the universal principles that are employed at every stage of production. The principles/heuristics are the foundation of TPS, driving the tools and peoples behaviour daily.
31 Figure 3.4 4P8 of Toyota Way, source Liker, 2003
Fujio Cho, President of Toyota Motors Corporation , has said (Liker 2003): "Many good American companies have respect for individuals, and practice kaizen and other TPS tools. But what is important is having all the elements together as a system. It must be practiced every day in a very consistent manner --not in spurts--in a concrete way on the shop floor."
The critical starting point for Lean Manufacturing is to identify the value for the ultimate customer. The first question in TPS is: "What does the customer want from this process?" It is about understanding a customers expectations in the purpose of the design production system, where maximum value is produced and waste is minimized. TPS is very much based on flow theory, which considers conversion (VAA) and flow (NVA, like inspection, waiting , moving ) activities. Conversion activities are bound together through flow activities. Thus flow activities must be taken under investigation to eliminate non-essential activities or simplify and make activities which can not be eliminated from production more efficient. Reducing the share of NVA activities is expected to generate one or more of the following benefits (Koskela 2000):
Lead time compression
8 4P is Likers provided set of Toyotas principles.
32 Variability reduction Simplification Increase of transparency Increase of flexibility
Conversion activities that conventional managerial principles take under consideration must also be made more efficient, according to the lean production philosophy.
Figure 3.5 Production as a flow process: simplified illustration. The shaded boxes represent NVA, in contrast to VAA, source Lauri Koskela 1992.
Under conventional managerial principles, flow activities are not being taken under control and improved. That has led to uncertainty and cost expansion of non-value adding activities. That is why material and information flows are taken under consideration during analysis in the new production philosophy. Flows are characterized by time, cost and value. Flow is the foundation of Toyotas success . Single-piece flow gives flexibility to TPS, which is essential to endure in the rapidly changing car market . All this demands a complete rearrangement of your mental furniture. Doing things the wrong way leads to the creation of "Muda". It is better when you focus on the product and its requirements, rather than the organization and the equipment, so all the activities needed to design, order and provide a product occur in a continuous flow.
Ohno had a vision. He took all the different production theories under consideration, the most important one being Henry Fords idea of mass production. He understood that Fords production system wasnt applicable to the Japanese market because its demands were many times lower. He understood that he had to be flexible and start by redesigning the production system. He spent hours and days on the shop floor in a chalk circle investigating the location of hidden "Muda". He took dramatic steps and redesigned the whole production system by employing Just-In-time (JIT), Jidoka
33 and many other principles and techniques. It was the beginning of TPS, now considered to be one of the best production systems in the world. It is important to see the world from another angle and to be ready to think out of the "box", to be ready to consider alternatives and be brave enough to try to employ them. Changing the way people think is important, and it can only happen if they are continuously trained and coached to see the world in a different way.
3.3 Philosophy of Lean Construction
Project-based management is made up of three sides of a triangle (see figure 3.6): organization, commercial terms and operating system. The LC approach starts by redesigning the production system, by implementing many different principles, techniques and tools, many of them adopted from Toyota to make workflow more predictable. Predictability gives freedom and creates new possibilities. When flow is made predictable by reducing variation , the following things will begin to happen: total system performance improvement, simplified coordination and the revelation of new opportunities for improvement.
Figure 3.6 Project-based management: three sides of a triangle, source Karlsruhe EGLC conference November 2009.
Management in construction consists of two different theories: production theory and project management theory. Production theory in LC is based on the TFV model, which is a foundation for how production in construction should be structured to facilitate operations and improvements (continuous learning).
34 3.3.1 TFV views as the foundation for Lean Construction
TFV theory is an integration of three different concepts of production. These concepts individually consider different parts of production; i.e., separately they do not cover all production processes and operations. Isolated employment of these concepts frequently results in low productivity and all the problems discussed in chapter 2. Koskela (2000) summarized the views of production according to each of these TFV concepts in table 3.1 below:
Table 3.1 Integrated view of production, source Koskela 2000.
When investigating these different concepts separately, it is easy to understand that they are partial. If integrated together, it would give us a more comprehensive theory of production. The main principles and sub-principles associated with these three different views of production are summarized below in table 3.2:
35 Table 3.2 Main and sub-principles of production, source Koskela 2000.
These principles gathered together in table 3.2 were the foundation or reference point for Koskela when he formulated the main goal of LC, which is following:
"Lean construction is a way to design production systems to minimize waste of materials, time, and effort in order to generate the maximum possible amount of value"
The goal of LC is to drive the process according to principles and explain what kind of interactions and activities are expected to achieve the best results.
3.3.11 Value in construction projects
The starting point for Toyota is the client/customer and the first question is always: "What does the customer want from this process?" Doing something else other than what the customer expects is always waste. Therefore, understanding the value for the customer should be as critical as it is in TPS. A clear and thorough client briefing is considered to be the most useful strategy for reducing variations (AlSehaimi and Koskela, 2008). Studying and understanding the value parameters and purposes of the client is a bilateral communication between the supplier and the customer, as illustrated in the following figure:
36 Figure 3.7 The conceptual scheme of a supplier-customer pair , source Koskela 2000,
Frequently, clients lack knowledge of construction management, and it is difficult for them to share their ideas. It means a client must be taught through multiple negotiations and study sessions to determine his/her value parameters and main objectives. In conventional management, investigation of value parameters was an issue only for the client and consultant, i.e., the experiences and knowledge of general contractors, the main suppliers, etc. were left out of the value generating process. Very often, the result is a design which is not constructible but consists of errors and omissions. LC enthusiasts recommend using integrated work groups, where not only the client and consultant are present, but also the general contractor and main suppliers, to use their experiences and knowledge as well. Their first aim is to confirm that the designed product is constructible; however, often they also bring innovation to the value generating process. Designers and contractors must understand that the primary object of the design process is to minimize building life cycle costs ­ direct and indirect ­ related to energy use, maintenance , waste disposal, and occupant health and productivity, to minimize environmental impacts throughout the building life cycle, including product manufacturing, construction, use/occupancy, and renovation/reuse or demolition, and to optimize indoor environmental quality. This can only happen through intensive design in the early phase of project delivery, where alternatives should be explored and analysed to choose a best solution. Emphasizing intensive design by using BIM supported applications has been seen to be very adequate. The use of virtual models makes information exchange and communication transparent and clear. It helps the client and other parties involved in the project, directly or indirectly, to work on the same page.
Basically, it all means that decisions made in earlier phases in the project delivery have a greater impact on results, and these decisions facilitate all the following stages of project delivery. All the values that were discovered in the feasibility phase and design facilitate construction by providing the information required to design the production system, organize operations, and couple these with
37 learning, resulting in performance improvements. The loss of value must be minimized by reducing and mitigating the peculiarities of construction that cause a high level of unpredictability.
3.3.12 Flow in construction
It is claimed in different research, articles and literature that the flexible single-piece flow, including accurate in-flows (resources feeding the transformation), is the key to Toyotas success. However, current construction production management tends to neglect the flow concept.
Establishing construction production system flow should be the starting point for (re)designing the production system. Construction processes must be seen as a network of transformation activities and operations, where the human factor is not of less importance . Koskela (2000) defines production in construction as being of the assembly-type; i.e., material flows are aggregated until they generate the end product. However, seeing construction as a form of manufacturing sounds quite complicated, while construction has its peculiarities.
Transformation and Flow concepts of production more or less overlap. Conversion activities are bound together through flow activities. These flow activities must be taken under investigation to eliminate unnecessary activities and simplify and make more efficient those activities that can not be eliminated from production (see also sub-chapter 3.2). Conversion activities must be also addressed and made more efficient.
Koskela (2000) points out that site construction has three general material flows (which have seven sub-flows, or prerequisites), while manufacturing has only two.
38 Table 3.3 Material flows in car production and site construction. The seat and window components are used for illustration. The concept of task is presented for comparison, source Koskela 2000.
These three are general flows on site which are divided into seven prerequisites to make the task sound , as shown in figure 3.8; i.e., all resources must be present to complete the task.
Figure 3.8 Comparison of a task-based construction process view and flow-based construction process view, source Koskela 2000.
The figure on the left represents the traditional construction process view (tasks are pushed on sub- contractors according to CPM) and the figure on the right represents the flow view of construction (considers current status of production, short-term planning ­ LPS). According to the new view, the execution of a task will start when all the prerequisites have been completed. Failure of just one of these usually leads to a making-do kind of waste (Koskela 2004). When managers are trying to avoid the idleness of their crew, equipment, etc., without thinking of consequences, they realize that work with one or more prerequisites missing . This generally has an impact opposite to that expected; i.e., an
39 increase of process time and variability, as well as a decrease in worker motivation due to the fact that workers must invent work for themselves.
Ballard9 (2002) also presented a general three flow model, based on the nature of the flows:
Directives Prerequisite work Resources
"Directives provide guidance according to which output is to be produced or assessed. Examples are assignments , design criteria, and specifications. Prerequisite work is the substrate on which work is done or to which work is added. Examples include materials, whether ,,raw or work-in-process, information that is input to a calculation or decision, etc. Resources are either labour, instruments of labour, or conditions in which labour is exercised. Resources can bear load and have finite capacities. Consequently, labour, tools, equipment, and space are resources." (Ballard G,. Tommelein I., Koskela L., and Howell G. 2002)
Koskela and Ballard might have a slightly different understanding of flows, but the aim is the same ­ reduced variability in these flows is a key to better projects. Glenn Ballard and Gregory Howell noted in their research in the early 90s that only 54 % of planned tasks are completed weekly. Thus, they developed LPS in 1992 to increase the reliability of planning as a mechanism for improving project performance (see sub-chapter 3.5.1).
3.3.13 Waste identification in construction
To create a flexible process (smooth and balanced flow) which also takes into account the current production status, then it is necessary to understand which activities do not create value, but only waste (in Japanese "Muda") and eliminate or mitigate them.
9 Glenn Ballard is a founding member of IGLC, a construction industry consultant, and a Lecturer in the Construction Engineering & Management Program, Department of Civil & Environmental Engineering, University of California at Berkeley .
40 In general, there are various levels of waste in construction projects, but here it is mostly focused on waste generated during the execution phase. Conventional management is task-oriented management and by its nature, neglects the idea of flow in construction, and basically this is what causes problems. The primary goal of LC is to avoid waste. Koskela (1992) identified the following 7 wastes in his report, following Ohnos waste identification system. In 2004, Koskela also added one more waste as the eighth kind of waste in construction, making-do; i.e. starting a process in sub-optimal conditions (see also previous chapter).
1. Quality costs 2. External quality costs 3. Lacking of constructability 4. Poor material management 5. Excess use of materials on site 6. Working time use for none -value adding activities 7. Lack of safety 8. Making-do
According to the Construction Industry Institutes research on the topic "Lean Principles in Construction" (2005), they identified and named three types of activities. CII determined that transformation/conversion activities are activities that consume resources and add value (value adding activities VA) to the product. All other activities are waste, and though in general there are two types of waste: first, Non-Value Adding activities, but Required (NVAR) ­ material positioning , in-process inspections and temporary work and support activities; second, Non-Value Adding (NVA) activities that consume resources but do not add any value and can be and must be removed from the production system immediately.
Koskela divided waste into two main groups: waste due to human action and waste due to flow of materials (Project management day in Tallinn, 2008). In the execution stage, waste caused by human activities occurs in two common construction situations: work inactivity and ineffective work (Serpell, Venturi and Contreras , 1995). Causes for work inactivity: travelling , idle work, resting, waiting time
41 and physiological needs. Causes for ineffective work: rework, inventing working and working slowly. Of course many of these causes are subjective, but to understand the time spent on value adding activities, all activities must be considered.
Waste can also be divided into the two following groups (Serpell, Venturi and Contreras, 1995): controllable and non-controllable. We can not control non-controllable activities as much as we wish or would like to, but the good thing is that they usually form a small part of construction uncertainties. Rather, it is people who create NVA (wastes from inadequacy). Uncertainty can be reduced by first admitting it and then negotiating with the owner on the matter of ends and means. Construction processes are subject to more uncertainty, while the process is repetitive only at the task level and production units are rarely static. Poor organizational management on site is a result of poor short-term planning, resulting in waste. This is an area which needs to be studied and would be a good topic for a student thesis.
3.3.2 The Lean Construction principles driven by the TFV model
Perhaps it is the right time and place to recall why we need principles/heuristics, before we get to the point. Principles are driven by the goals needed to build up the processes and operations in a systematic way. These explain how activities and operations within a production system should contribute to the general project objectives.
Different authors have provided lists of lean principles, both in the lean production literature (Liker 2003; Schonberger 1996; Womack and Jones 2003) and the lean construction literature (Koskela 1992; Koskela 2000). But, as a study of lean principles shows, there is still no common rule about which principles are most suitable for the construction industry. Probably, this is just the current situation, while lean construction as a theory is still under development.
This part of the thesis is based on the CII research summary 191-1, on the topic ,,Lean Principles in Construction", October 2005. CII conducted research because the development and application of lean principles in manufacturing have had a great positive impact on the production system. Many manufacturing companies are using half of everything: manpower, space, etc. Its great success is what
42 motivated CII to conduct this research to determine if these principles are applicable to the construction industry as well. The result or output was the lean wheel as shown below. Principles are most efficient only when applied coherently as a whole.
Liker (2004) divided TPS principles into four categories: philosophy, process, people and partners , and problem solving. CII generated five main principles instead, which can be taken as categories which consist of many sub-principles:
1. Customer focus 2. Culture and people 3. Workplace standardization 4. Elimination of waste 5. Continuous improvement and built-in quality
It is a result of extensive studies of lean production and construction principles. CII also summarized many sub-principles for each top level principle and structured it into a simple tool called "The Lean Wheel". Its idea is to simplify and organize lean principles into a format that it is easily understandable by everybody .
Figure 3.9 The Lean Wheel for a simple presentation of Lean principles, source CII 2005 43 3.3.3 Management theory in construction
Production management is divided into two main theories: production theory and management theory. Koskela (2000) suggested that there are three different views to production, each providing principles and methods for the production system ­ the TFV model. When a construction production system is structured according to the TFV model, it becomes the basis for management in construction; i.e., the design of a production system facilitates operations and improvements. Indeed, production system design is about sequencing a series of transformation activities that convert inputs to outputs (production process). This is a view that conventional management considers, but in lean construction there are transformation activities (the production process) and operations (human activities, external processes, etc.) which both must be considered to get better project outcomes. These two are dependent on each other, and it is necessary to see it as a holistic system whose aim is to achieve TFV goals. There are plenty of IGLC conference papers which analyse the conventional management doctrine and compare it with many other management theories and methods (for example Scrum, LPS, etc.). The result is always more or less the same, as the current management theory is deficient and implicit for the construction industry. Construction theory must consist of the elements listed in following table.
Table 3.4 Ingredients of a new theoretical foundation for project management, source Koskela and Howell 2002.
LPS, originally developed by Ballard and Howell, is seen as a more comprehensive controlling system which takes into account the current project status instead only forecasting. LPS meets most of the
44 requirements represented in table 3.4. In the following section , LPS is discussed in terms of theory, principles, and techniques it employs.
3.3.31 Predictability in flow and processes (LPSTM)
In traditional management, planning is based on CPM. This technique uses work-break down structuring to create work clusters (tasks) which must be completed to deliver a project. Afterwards, tasks can be measured in terms of resources required to perform them. The next step is about putting tasks into a logical sequence. The main problem with this well-known technique is that it is unpredictable, as it rejects intermediate and frequently short-term planning. It is based on forecasts and usually done by the main contractor managers who are not the ones responsible for completing the given tasks. Research conducted by Glenn Ballard and Greg Howell early in the 1990s revealed that only 54 % of jobs planned for a week were finished; i.e. short-term planning is insufficient and resources which are not well planned are pushed on the sub-contractors, where sub-contractors have no rights to say "NO" if they want work; i.e., at the same time, they can not promise to finish it within the planned time and cost (Howell and Ballard 1994).
To resolve this problem, Glenn Ballard and Greg Howell in 1992, members of IGLC, invented the LPS production control system to make workflow more predictable. LPS, based on lean construction principles, aims to increase reliability of planning and thereby to improve performance.
The starting point for them was the following: all plans are forecast and all forecasts are wrong!
LPS is about making workflow more predictable and learning from your own failures, and it is less important to understand the root causes. It is achieved by making the "last planner" plan his work together with other participants as early as possible and share his expertise in his particular field ("pull" planning). Tasks are made sound by executing constraints analyses, and tasks that are sound will be passed to weekly work planning. From the authors experience, there are companies in Estonia who do weekly work plans, but not as systematically as LPS requires, but rather based on demagogy. They also do not measure their performance, while in LPS it is done by measuring PPC, and this enables real time process tracking and learning.
45 LPS is driven by next principles (the foundation for LPS):
1. Plan in greater detail as you get closer to doing the work 2. Produce plans collaboratively with those who will do the work 3. Reveal and remove constraints on planned tasks as a team 4. Make reliable promises 5. Learn from breakdowns
3.3.311 Levels of the Last Planner System
LPS can be understood as a mechanism for transforming what SHOULD be done into what can be done, thus forming an inventory of ready work, from which Weekly Work Plans can be formed . It is about work structuring which extends in scope from an entire production system down to the operations performed on materials and information within the system. Assignments that are included in Weekly Work Plans are the promise by the last planner what they actually WILL do in the following week. Thus we can say LPS has two main focuses: short term planning and the development of a social system on site. LPS consists of five different levels, each level more detailed than the preceding one. In the following, each level of LPS is briefly discussed.
Figure 3.10 "The Last Planner System of Production Control: 5- Connected Conversions", source Ballards and Howells presentation at Karlsruhe conference 2009.
46 Master scheduling
The master schedule is produced during front end planning and represents the milestone level of project planning by specifying the timing of the various phases a project goes through. This schedule is broken down mainly by function , area, or product. It covers the entire project duration and presents activities at a coarse level with a long planning horizon. As a product of work structuring, the master schedule reflects important milestones dictated by project constraints and objectives. Also long lead times will be determined, so they can be taken under consideration during construction. The master schedule is usually created by using applications based on the CPM model.
Phase scheduling
The phase scheduling technique is used to develop a more detailed work plan that specifies handoffs between the specialists involved in that phase. These handoffs then become goals to be achieved through production control. The level of detail must be as accurate as needed to assign handoff upon someones responsibility. The phase schedule produced is based on targets and milestones from the master schedule and it provides a basis for look- ahead planning. LCI recommends using pull techniques and team planning to develop schedules for each phase of work, from design through turnover . The "pull" technique is based on working backwards from the target completion date (some- times called " Reverse Phase Scheduling"), which causes tasks to be defined and sequenced so that their completion releases work. Thus, the general rule of the "pull" technique is scheduling only works that release other works. This helps to reduce overproduction. It involves all parties who are going to be included in this particular phase.
Typically, team members write on a sheet of paper (usually a sticky ) brief descriptions of work they must perform in order to release work to others or work that must be completed by others to release work to them. They tape or stick those sheets on a wall in their expected sequence of performance. By seeing the results of planning, the feeling of responsibility to each other is increased.
47 Lookahead planning
Lookahead planning is at the intermediate level of the planning system hierarchy. Lookahead planning explodes tasks into an operational level, providing detailed information for budgeting and scheduling. Lookahead scheduling is about screening out tasks that are not sound in matter of prerequisites (constrains analyses) and making ready for completing them. Lookahead planning is dedicated to controlling the flow of work through the production system and streamlines the work flow for the Last Planner. This method of scheduling usually covers 3-6 weeks, but the time span can be wider depending on how reliable the in-flow of resources is; the length of guaranteed time that prerequisites are available on time. It is very important because the certainty of work flow from one production unit to the next is the key to higher productivity.
Weekly work planning
Weekly work plans are the highest level of detail prior to carrying out the work. This level of scheduling is built around promises (yes, no or if) that are given by the parties involved in a project. An agreed program defines when tasks should be ready and acts as a request to the supplier to do the task. The last planner only promises once after they have clarified the conditions of satisfaction and if they are sure that the task can be completed on time.
Learning
After the execution of tasks comes the measurement of outcomes of processes and operations. This is done on the basis of PPC; i.e., the number of successfully completed tasks is divided by the number of tasks planned for the week. Tasks that were not completed on time in accordance with the quality criteria will be studied by using the "5Whys" method to understand the root causes for the failure. There are companies in Estonia who do weekly work planning, but they do not measure productivity.
48 3.3.4 Discussion
LPS has been in use for several years and has proven to have a great impact on projects, leading to more productive processes. Many organizations have improved their planning by employing LPS. It is a relatively simple technique based on lean construction principles including several simple tools like the "5Whys", etc. Still, we can not say that this tool is perfect. It has some gaps that should be improved, such as resource management.
3.4 Conclusion
LC is an adaptation of Toyota philosophy, principles and methodologies, including other relevant theories, to the construction industry, originally by a group of enthusiasts, who established IGLC in 1993. LC is a new and innovative construction management model, which has proven its validity even in very difficult projects. Construction management is divided into two parts: production theory and project management theory. LC addresses them both. It is a comprehensive theory based on a strong theoretical foundation, with methodologies that help to put theory into practice.
49 CHAPTER 4- BUILDING INFORMATION MODELLING
BIM is a new business model which requires participants to change their mental furniture. For the people involved in a project it is a platform for collaboration, as they work according to the same model. Therefore, it is essential to understand the workflow of BIM. In Estonia, there are only a few firms who have been using BIM for more than a year and are doing it comprehensively. The reason for this is a lack of professionals who are trained to use BIM. BIM is a new innovative business model that is still a buzz word for many professionals in the construction industry. Therefore, the objective of this work is to briefly define what a/the BIM is. It is not based solely on a literature review, but includes some examples from the Crusell Bridge case study included in the appendix.
4.1 Definition of BIM: parametric modelling
What does this three letter acronym actually mean ? Many scholars and practitioners define it a bit differently, but the general concept remains the same. The glossary of the BIM Handbook (Eastman, Teicholz, Sacks, Liston, 2008), one of the best-known publications in this field, defines BIM as a verb or adjective phrase to describe tools, processes and technologies that are facilitated by digital, machine -readable documentation about a building, its performance, its planning, its construction and later its operation. The result of the BIM process is a building information model. BIM software tools are characterized by the ability to compile virtual models of buildings by using machine-readable parametric objects. BIM Handbook authors have also stated that BIM enables more integrated design and construction, resulting in better project outcomes. Therefore, it is expected to provide the foundation for leaner processes.
50 4.1.1 What BIM is not
Most people associate BIM principally with 3D10 modelling, but this is a misconception. It is a buzz word and therefore should be explained. Instead of giving a definition, the authors of the BIM Handbook describe products that do not utilize BIM technology. With these tools it is possible to create the following kinds of models (Eastman, Teicholz, Sacks, Liston, 2008):
Models that contain 3D data, but no object attributes: These are models that are great for visualization, but have no intelligence at the object level. They integrate no other information than 3D parameters.
Models with no support of behaviour: There are models that define the object but can not adjust their positioning or properties, because they do not utilize parametric intelligence. Making changes is very labour intensive, and there is no protection against inconsistencies or inaccurate information in the model.
Models that are composed of multiple 2D reference files that must be combined to define the building: It is impossible to ensure that the results of the 3D model are consistent, feasible, countable, and display intelligence with respect to the objects contained within it.
Models that allow changes in one view that are not automatically reflected in other views: This allows errors in the model that are very difficult to detect.
4.2 Interoperability
No BIM application exists which can model and analyse data throughout the whole facility lifecycle. The cornerstone for BIM implementation is that different applications must interoperate directly or by using internationally accepted standardized information models. At the end of 1994, 12 American companies created a consortium to develop a standardized information model. In 1997, the non-profit
10 3D computer graphics: computer graphics modelling three-dimensional objects.
51 organization was named the International Alliance for Interoperability (IAI). Currently, the two main standardized building product data models are the following (Eastman, Teicholz, Sacks, Liston, 2008):
Industry Foundation Classes (IFC) ­ used for building planning, design, construction and management; CIMsteel Integration Standard Version 2 (CIS/2) ­ used for structural steel engineering and fabrication.
Both IFC and CIS/2 include data about geometry , relations, processes and materials, performance, fabrication and other properties needed for design and construction. These are neutral information models and can be created using applications that support the IFC standard.
4.3 Implementation of BIM
When a team is collaborative, committed to the overall goals of the project and passionate about finding the best solutions, good things start to happen. The best value for the customer comes from driving out waste, and this only happens when the three aspects previously mentioned are present.
4.3.11 Collaboration
The Crusell Bridge case study revealed that while BIM is a new methodology, collaborative team work involving all the participants is essential for project success. Emphasizing collaboration comes through educating project participants about BIM process outcomes. It becomes even more important when BIM is a new concept for the people involved in a project. In the Crusell Bridge project, BIM offered many new features which were tested. Therefore, this project became a pilot project for all the participants.
For collaboration, exchanging information in an adequate way is crucial for the success of a project. Thus, parties who are responsible for modelling, information exchange, and modification of the model, must be identified throughout the entire projects lifecycle (see also 4.3.12). During the BIM process, data is collected and integrated into the building information model throughout the entire facilitys lifecycle, and can then be used whenever needed, e.g., for exploitation, renovation or demolition. One 52 possible and fast way of sharing information is using the model synchronization method over the internet . This is a fast way of sharing information.
Krygiel, Eddy and Nies, Bradley (2008) defined the integrated use of a model as shown in figure 4.1. Workflow is divided into four collaborative steps (adapted):
1. Architects and consultants work on the same model; 2. Stage of refinement, where the model is passed to the contractor and building team 3. Model is adjusted to reflect the change that happened in the field. 4. Then it is shared with owner and facilitys maintenance operators
Figure 4.1 The traditional and integrated approach to design review.
4.3.12 Planning use of BIM
From the Crusell Bridge project, we learned the following: a comprehensive plan for BIM execution is needed to get the best value from BIM process. Within the Computer Integrated Construction Research Program in 2009 the "BIM Project Execution Planning Guide ­ Version 1.0." by the buildingSMART allianceTM was created. The guide describes four steps for creating the BIM execution plan.
These four steps are the following:
53 1. Identifying high value BIM uses during project planning, design, construction and operational phases 2. Designing the BIM execution process by creating process maps 3. Defining the BIM deliverables in the form of information exchanges 4. Developing infrastructure in the form of contracts, communication procedures, technology and quality control to support the implementation
Compiling a BIM Execution Plan should be done as early as possible in a construction project by involving as many important parties as possible (owner representative, designer, constructor, sub- contractors and etc.). First, the general project value parameters for the client should be identified. This is probably the key factor for successful project delivery. Those measurable value parameters, both from the project and company perspective, facilitate the use of BIM. Goals set must be justified by considering BIM concept and functionalities; e.g., tracking project progress during execution. Now, when the goals of the BIM execution plan are set, the functionalities for each goal can be allocated to achieve these goals. The Computer Integrated Construction Research Program identified twenty -five BIM uses by investigating the use of BIM and consulting with industry experts. However, this list is not complete.
A comprehensive and explicit set of goals and BIM uses become the foundation for the second step in creating the BIM execution plan. The second step: making the BIM project execution process map by considering inputs and outputs of each stage that contribute to the general project goals. The map is an organizational structure of the BIM process clarifying the flow of information, responsibilities and responsible parties.
The third step in creating a plan is defining the minimal information exchanges between project processes and participants. It is recommended to use the pull technique in this step; i.e., downstream members identify the information needed to execute their processes.
After the previous steps are completed, the team must develop the infrastructure contributing to project outcomes and the BIM process. This will include the definition of the delivery structure and contract
54 language , defining communication procedures, defining the technology infrastructure, and identifying quality control procedures to ensure high quality information models.
Thus, following these four steps should result in a comprehensive BIM execution plan, which must be implemented in practice. At the same time, it is not only about implementing it, but also about measuring the outcomes and modifying the plan in the next steps and processes if necessary. It must be understood that the development of the BIM concept and processes in general is still incomplete and under development. Thus, constraints during the implementation of BIM will definitely occur, even if you have a great BIM implementation plan, but an adequate plan should help to predict these obstacles and provide procedures to overcome them. Consequently, it is important that the team is committed to the goals and passionate about overcoming these obstacles in a collaborative way. From a future perspective, problems and failures in project delivery must be tackled, and the root causes for each of them must be discovered to prevent their occurrence in subsequent projects.
4.3.13 BIM functionalities/uses
The great value arising from the use of BIM comes from the functionalities it offers. Sacks11, Koskela, Dave , and Owen (2009) juxtaposed BIM uses with Lean construction principles to understand if there is a synergy existing between these two new, innovative business models, no matter if they are positive or negative. For that they generated a short table listing BIM uses, as shown below followed by a short description of the main uses:
11 Associate Professor, Faculty of Civil and Env. Engineering, Technion ­ Israel Institute of Technology, supervisor of this thesis..
55 Table 4.1 BIM functionalities, source Sacks, Koskela, Dave and Owen 2009.
Visualization:
A virtual model makes it possible to evaluate the aesthetic look of a design and functional performance. Most of the applications that support BIM principles allow rendering of the design to some extent so it is understandable to a person with no technical background. Also, it is recommended to use the model during coordination meetings and negotiations to ensure that everyone associated with the project has a common understanding. Visualization is the greatest benefit of BIM.
Maintenance of information and design model integrity :
Information is inserted once and can be used as often as needed and for various purposes;
56 Automated clash detection between permanent and temporary structures, which makes it possible to eliminate problems early in the design process, where making changes and rework is less costly than during the construction stage.
Automated generation of drawings and documents :
Various BIM applications provide functionality to automatically generate project documentation and drawings (for example quantity take-offs in Excel or ASCII format). Often it is necessary to manually straighten and modify them. As changes in any part of the model will be reflected in all the other parts, generating new and improved documentation and drawings is less time consuming.
Collaboration in design and construction:
The same model is used for coordinating work between the designer and constructor, emphasizing the need for collaboration. For that it is important to understand the processes and workflow of BIM. Thus, the training of project participants is crucial for success.
Rapid generation and evaluation of construction plan alternatives:
Some BIM applications automatically generate a list of tasks according to the objects that are inside of the model; It is possible to visualize and simulate construction processes: general site planning, using model for coordinating meetings, performing different scenarios and etc.; Visualizing construction schedules: 4D (3D model + time/schedule) and 5D (4D + money) in terms of space and money.
Online/electronic object-based communication:
BIM enables visualization of the current state of the project (process tracking) and this information can be shared with others. This is especially important for the client.
57 The following can be added to objects in the model: information for the fabrication date, work starting and ending dates , etc. This should allow better logistical planning. With the information obtained directly from the model, it is possible to drive machinery in the supplier's factory.
This is a short summary of how BIM can be made use of, but these are probably the most important right now. The description of them is based on the authors own experience gained while carrying out the Crusell Bridge case study and visiting Finish construction companies.
4.4 Conclusion
BIM is an innovative business model emphasizing construction project prototyping. It enables virtual design and construction planning and should result in fewer problems during the execution and maintenance phases. For many, BIM is still a buzz word, as they are not familiar with the BIM model. Therefore, it is essential to educate people in the private sector and students at universities in the matter of BIM and its benefits and obstacles. Lack of training is the main reason why BIM is not being made significant use of in the Estonian construction industry. As BIM requires a new way of thinking, people with a steep learning curve must be committed and passionate in a collaborative environment to be successful BIM users . The author of this thesis argues that a comprehensive use of BIM should be the first step in the near future to improving productivity in the Estonian construction industry.
58 CHAPTER 5- INTEGRATION OF LEAN CONSTRUCTION AND BUILDING INFORMATION MODELLING
In the first chapter, the main problems connected with the construction industry were discussed, more specifically, those related to the Estonian construction industry. The problems were described, and this was followed by an in-depth analysis of root causes. This became a premise for LC and BIM in this work (see also chapter 3 and 4). It is not claimed that LC and BIM are the only and the best solutions to address the problems in the construction industry, but these two are the most commonly known worldwide and have proven their validity. This, the fifth chapter is about the integration of these two models. The purpose of this work is not to define any particular workflow, to describe how these two can be simultaneously used or provide a new model of how these two independent concepts could be integrated, but rather to provide an introduction to existing forms and studies.
5.1 Theoretical work of integrating Lean Construction and Building Information Modelling
LC and BIM are different initiatives , but both have proven to have a profound impact on the construction processes. "The Interaction of Lean and Building Information Modelling in Construction" compiled by Sacks, Koskela, Dave and Owen (2009) is a thorough, theoretical and practical literature review of the understanding of the synergies between LC and BIM. This white paper juxtaposes 16 lean heuristics/principles with the 8 BIM functionalities/uses to determine if the use of BIM in construction processes promotes leaner processes. Altogether, 56 interactions were discovered between LC and BIM, including positive and negative relations. For most of these interactions the evidence has
59 been found and presented. Thus, synergy between these two does exist. The article makes it easy to understand BIM processes and how it should or should not be used with LC.
The authors claim that this list of interactions is not a complete list, but rather a basis for future studies and research. Still, this work proves that a great synergy between these two exists, and it is recommended to use BIM to achieve leaner processes. But also as it is understood from this comprehensive study and also in the case study described in the third chapter of this thesis, BIM and LC both still are evolving and therefore, most professionals are still learning. So it may be a good strategy to carefully define benefits that are desired, accordingly to design, execute manageable BIM/lean experiments, and to proceed in incremental stages towards harnessing even more positive interactions between these two initiatives (Sacks, Koskela, Dave and Owen, 2009).
"The 6th annual survey of construction owners" by CMAA (2005) has stated it more succinctly: the biggest cost impacting construction today is that of inefficiencies built into the way projects are run and managed ­ not costs of raw materials like steel and concrete, or the cost of labour. By recognizing this, the LC and BIM professionals have started to create coherent, integrated project delivery process models with the aim of breaking down barriers and silos . There have been several different attempts, but the ones currently worth mentioning are Virtual Design & Construction (VDC) linked with Lean Project Delivery System (LPDS) and IPD. More specifically, IPD is introduced as it is a further development of VDC and LPDS, where collaboration is emphasized by implementing relational contracting.
5.2. Integrated Project Delivery (IPD)
IPD is an attempt to address all the inefficiencies and problems revealed in the second chapter of this thesis. IPD employs the contracting method, which brings together all the parties involved in a project. The objective is to make them work towards the same objectives by considering the full life cycle of the facility. IPD encourages early contribution of expertise and requires proactive involvement of key participants. Responsibility is given to the person who is most able , by keeping in mind the "best for the project". There is a possibility to implement IPD without BIM, but it is recommended to use BIM as a platform for collaboration and leaner processes. IPD, as an alternative project delivery method,
60 has been in the focus of the construction industry over the last five years. The following table illustrates the differences between traditional delivery methods and IPD:
Traditional Project Delivery Integrated Project Delivery Fragmented, assembled on "just-as An integrated team entity composed teams needed" or "minimum-necessary" basis, key project stakeholders, assembled strongly hierarchical, controlled early in the process, open, collaborative Linear, distinct , segregated; knowledge Concurrent and multi -level; early gathered "just-as-needed"; information contributions of knowledge and process hoarded; silos of knowledge and expertise; information openly shared; expertise stakeholder trust and respect Individually managed, transferred to the Collectively managed, appropriately risk greatest extent possible shared Individually pursued; minimum effort for Team success tied to project success; compensation/ maximum return ; (usually) first-cost valuebased reward based Paper-based, 2 dimensional; analog Digitally based, virtual; Building communications Information Modeling (3, 4 and 5 /technology dimensional) Encourage unilateral effort; allocate and Encourage, foster, promote and support agreements transfer risk; no sharing multilateral open sharing and collaboration; risk sharing Table 5.1 Comparison of traditional and IPD process, source AIA and AIA California Council 2007.
5.2.1 Definition of IPD
The American Institute of Architects (AIA) defines IPD as "a project delivery approach that integrates people, systems, business structures and practices into a process that collaboratively harnesses the talents and insights of all participants to optimize project results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction" (AIA and AIA California Council, 2007).
IPD can be used with a variety of contractual arrangements , but at the minimum, IPD includes tight collaboration between owner, architect and general contractor. Thus, IPD is not suited to the DBB project delivery model, as parties are contracted during various stages and chosen by the lowest bid.
61 5.2.2Principles of IPD
IPD, built on collaboration, is emphasized by using BIM and relational contracting. Relational contracting is based on trust and collaboration that encourages parties to focus on project outcomes, rather than their individual goals. Better project outcomes can be achieved only when people are ready and willing to change their thinking. Thus, to be successful and embrace the benefits of IPD, the project parties must follow the next nine principles (AIA and AIA California Council 2007):
1. Mutual respect and trust: All the parties in an IPD project must understand the value of collaboration and be committed to working as a team in the best interests of the project. All key members must be involved as early as possible from owner to end user . Roles are not restrictively defined, but assigned on a "best person" basis.
2. Mutual Benefit and Reward: All team members and participants benefit from IPD. In IPD the members are involved as early as possible, and IPD compensation structures recognize and reward early involvement. The compensation structure motivates the search for better solutions and value added by the temporary organization, and it rewards "whats best for the project". Incentives are tied to the achievement of project goals or even more.
3. Collaborative Innovation and Decision Making: Team members are motivated to be innovative, and it can only happen when ideas are judged on their merit , not on the authors role or status. Each partys idea will be taken under consideration equally, no matter his or her status in the project. Key decisions are evaluated by the team and, to the greatest practical extent, made unanimously.
4. Early Involvement of Key Participants: Key members are involved as early as possible, and this should result in better decision making, improved due to the early involvement of knowledge and expertise of all key members. For example, 70-80 % of energy consumption of a facility is determined by schematic design (Krygiel, Eddy, Nies and Bradley 2008).
62 5. Early Goal Definition: Defining feasible general project goals together is the first step in the project. Insight from each participant is valued in a culture that promotes and drives innovation and outstanding performance, holding project outcomes at the centre within a framework of individual participant objectives and values.
6. Intensified Planning: Dont reduce planning or design effort, but rather put emphasis on it. This should result in increased efficiency and savings during execution.
7. Open Communication: IPDs focus on team performance is based on open, direct, and honest communication among all participants. Responsibilities are clearly defined in a no-blame culture leading to identification and resolution of problems, not a determination of liability. Disputes are recognized as they occur and are promptly resolved.
8. Appropriate Technology: Integrated projects often rely on cutting edge technologies. Technologies are specified at project initiation to maximize functionality, generality and interoperability. Open and interoperable data exchanges based on disciplined and transparent data structures are essential to support IPD. Because open standards enable better communication among all participants, technology that is compliant with open standards is used whenever available.
9. Organization and Leadership : The project team is an organization in its own right, all team members are committed to the project teams goals and values. Leadership is taken by the team member most capable in regard to specific work and services . Often, design professionals and contractors lead in areas of their traditional competence with support from the entire team; however, specific roles are necessarily determined on a project-by-project basis. Roles are clearly defined, without creating artificial barriers that chill open communication and risk taking.
63 5.2.3 Organization, operating system and commercial terms
Project-based delivery systems, like construction, form the three sides of a triangle, or in other words, they have three basic domains: organization, operating system and commercial terms (see also chapter 3). IPD tries to address all three aspects by employing new innovative business models and techniques. It is a coherent system which should be structured in a way that all these aspects are aligned and balanced, keeping in mind each partys own objectives. The operating system is aligned according to the LC model, which is complemented by using new innovative IT solutions like BIM. Commercial terms are addressed by employing relational contracting methods originating from alliancing, invented in the early 1990s. These two domains address the third, organization, which must be built on trust and collaboration, where all the parties involved are committed to the general project goals. IPD offers principles and techniques that embody these three domains/aspects comprehensively. Each domain is discussed below.
5.2.31 Project organization
Conventional project delivery models fragment project delivery, and this leads to the inefficiencies and problems revealed in the second chapter. Organizationally, all IPD projects share at least one thing in common: construction managers and some key trade contractors are involved in the project with the owner and the designers beginning from the early stages of design, as shown in the next figure ( Thomson , Darrington, Dunne and Lichtig 2009).
64 Figure 5.1 Comparison of IPD and the traditional approach, source AIA and AIA California Council 2007.
Contractors are selected on the basis of their qualifications rather than cost, and it is recommended that team members are involved in goal-setting. Thus, participants involved will have a higher level of understanding of the project objectives. The expertise and knowledge of contractors will make it possible to make better decisions on matters of constructability, cost and value for the owner. It offers a chance for a new project culture to emerge . To emphasize collaboration, some IPD projects collect the project team in one place, putting them together into one "Big Room ". People are much more likely to work out problems with their friends than strangers. Another technique is to use BIM, Project Management Information Systems (PMIS), and other IT solutions that require considerable time for collaboration as a platform for teamwork in IPD projects. For example, using BIM, collaboration is required to deliver a building product model.
Leadership in IPD projects is usually in the hands of the Core Group (consisting of at least the owner, the main designer and the main contractor), whose responsibilities are day-to-day management and
65 leadership, and delegating decisions to the executive committee. It is important that the executive committee members, who are more than just mere managers, are committed to the project. The benefits of IPD will only be realized with a change in culture, in the way team members relate to each other. Emphasizing the importance of making and keeping commitments and tracking the teams performance helps team members focus on and improve the reliability of their promises. Reliability, in turn, helps build trust (Thomson, Darrington, Dunne and Lichtig 2009).
5.2.32 Operating system
In IPD projects, the operating system is built on the lean construction model (see chapter 3). It is a philosophy, culture and discipline with a set of preferred behaviours and a continually increasing repertoire of tools (Thomson, Darrington, Dunne and Lichtig 2009). In the following section, the most widely used IPD tools are discussed, but these are only a few of many. LPS, discussed in the third chapter of this thesis, is also used in IPD projects. Still, to prevent any misinterpretation, the tools and techniques can create waste if the concept is not grasped comprehensively. Learning lean is difficult, disciplined work which requires abandoning traditional thinking.
Lean tools:
Plan-Do- Check -Adjust/Act ( PDCA ) ­ Sheward, further developed by Deming . The cycle is the heart of the problem solving process in lean construction. A lot of time is spent on developing a detailed understanding of the problem that must be solved. PDCA consists of the following four stages:
1. Plan ­ Develop a detailed understanding of the problem and offer a solution. 2. Do ­ Implement what has been planned 3. Check ­ Measure the results of Do 4. Adjust/Act ­ Compare the results with what has been planned; if the results are as expected, then standardize the improved process; if not, then plan again and go through all the other steps again.
66 A3 reports ­ based on PDCA thinking and processes, it is a way of organizing and analysing issues. Originating from Toyota, A3 typically states the background, the problem, the current state, the future desired state and proposed counter- measures to get to the future state all on a single 290 by 420 piece of paper (A3) (Gupta, Tommelein and Blume 2009). A3 reports foster dialogue between all the parties working on a project or connected by a specific issue, and this should lead to better decisions, as all the information for decision-making is available. A3, if implemented properly should appear simplistic, so it could be taken up in a minute, as practitioners have stated.
Value stream mapping ­ an important tool that helps a team to understand the business process step by step, to discover how value is produced, and to identify hidden waste. Very often business processes are not easy to grasp, but by visualizing and documenting the current state of the processes, it helps all the parties involved to work on the same page and to optimize the processes. This is a tool that can and should be used during all the different stages of a construction project. In general, the workflow for developing a general understanding is as follows (Thomson, Darrington, Dunne and Lichtig 2009):
1. Identify the target product ( deliverable ), product family or service . 2. Draw a current state value stream map, which shows the current steps, delays and information flows required to deliver the target product or service. This may be a production flow (raw materials to the consumer ) or a design flow (concept to launch ). 3. Assess the current state value stream map in terms of creating flow by eliminating waste. 4. Draw a future state value stream map. 5. Implement the future state. 6. Assess and adjust the new process as needed.
BIM and Real Time Estimating (see also chapter 4) - BIM is seen as a tool that enables a leaner environment where all the parties working on a project are forced to collaborate. BIM as a process has many useful functionalities and outcomes. One example is an automated estimation of quantities, which in turn leads to rapid cost estimation. In the Shutter Health project, they started estimating the cost as soon and as often as possible to develop a general understanding of whether the design was
67 meeting project goals. It created an environment where cost was driving the design rather than vice versa (Khemlani 2009).
Target Value Design (TVD) - a management practice that drives design to deliver customer values and develops design within project constraints (Ballard 2008). It is a quite new and emerging tool that many scholars are studying extensively right now, for example at Loughborough University. When implementing relational contracts, the set-based design is also included as a part of TVD. It is a technique, where in the early part of the design process, many design alternatives are created and assessed until the best solution for the project is chosen.
5.2.33 Commercial terms
IPD projects take a variety of approaches to change the commercial framework of risk allocation and compensation in order to better align the commercial interests of parties with a collaborative approach and overall success on the project (Thomson, Darrington, Dunne and Lichtig 2009). A construction project is characterised as a temporary multi-organization, where each player can and will influence other participants in the project and therefore the whole project. Construction is a network of commitments. In IPD, the members collectively share and manage risks, for example in the Shutter Health project, the 11 members of the project engaged under the same contract, the Integrated Form of Agreements (IFOA), where they became equally responsible for achieving project goals (Khemlani 2009). The "win-win" or " lose -lose" environment was created by tying each participant's incentives to general project outcomes. Thus, participating team members mutually benefit when project cost savings are achieved and mutually share the risk of cost overruns.
5.2.4 Legal relationships
For IPD, there are several suitable contracting methods, but the least supportive is the DBB delivery model. In particular, it is not possible to build up IPD processes based on DBB. Hence , it is not the purpose of this work to define any of the contracting models suitable for IPD, but rather the main concerns that must be addressed with contracts in IPD processes. Commercial terms in IPD must emphasize partnering, working towards the same objectives. Another issue that legal terms must address in IPD processes is the structure of disputes ­ how disputes and claims between different
68 parties are solved. Another issue has emerged with the employment of BIM in a project that must be addressed with a contract, specifically, the issue of intellectual property. It is necessary to define how and who can use the model. Therefore, it is recommended that a client gain possession of the model upon completion of the project, so that disputes in this matter do not occur.
5.2.5 Discussion
IPD is a new approach to the delivery of projects; it embodies LPDS and VDC ideas, where collaboration between different stages is emphasized by implementing the appropriate contracts. This approach breaks down the barriers between different stages and makes participants iteratively work towards the same project goals. In IPD, only a "win-win" or "lose-lose" situation exists for participants, including the client.
5.3 Empirical evidence for LC and BIM synergy
The author of this thesis in cooperation with his thesis advisor have compiled the Crusell Bridge case study on the extensive implementation of LC and BIM. This case study will be included in the second edition of the BIM Handbook, which will be published in the near future. Also, the author has done some interdisciplinary study and visited Finish construction companies on several occasions, as they are advanced users of LC and BIM. In the following section, the findings are shortly described.
5.3.1 Crusell Bridge case study
The Crusell Bridge is a cable stayed bridge, commissioned by the City of Helsinki 's public works department, connecting the western edge of Jätkasaari with Ruoholahti. Jätkasaari, a part of the former West Harbour, near the city centre of Helsinki, is being transformed into a new maritime urban district . Cargo operations have been moved to another part of the city to make room for development of some 9,000 new dwellings, giving rise to the need for a new road bridge. Figure 5.2 shows a rendering of the cable-stayed bridge in its setting in Helsinki harbour.
69 Figure 5.2 A rendering of the new Crusell Bridge in Helsinki harbour
During the design and construction process, the project team implemented both BIM technologies and LC principles and tools. This case study focused on the construction stage of the project, highlighting the use of BIM and LC.
Modelling as a virtual representation of reality provided multiple benefits for the parties involved in the Crusell Bridge project. According to all project participants, the intensive use of BIM for construction management enabled better management and organization, as well as a savings in time and money.
The case excellently illustrates how BIM can be used in a bridge project. The team's willingness and openness to use BIM and new management methods (LPS) gave all of the parties the opportunity to experience and learn from their own failures as well as from their successes. Great knowledge and experience was gained, which has already found expression in enhancements and improvements made to the delivery processes for future projects. While these methods will become common in complex projects of this kind, there will always be problems of course and the Crusell Bridge was no exception. Given that such use was new for the entire team, it is understandable that obstacles were encountered and problems occurred. The different ways the problems were tackled and the steps taken to remove or mitigate them were the drivers of positive change. Antti Karjalainen from WSP Finland said that, "the project results, both positive and negative, have been used as the basis for bridge BIM development and other software enhancements".
Finally, a summary of some key lessons learned during the project:
70 Plan using BIM and LPS from the very beginning of the project: set objectives, conduct initial training and create an environment and willingness for learning and improvement. Use the model to complement construction management techniques (planning, control, information exchange, meetings, quality control, etc.). Use the model synchronization feature to achieve fast information exchanges. Use 4D scheduling to help understand and assess if the network of commitments created during reverse phase scheduling is realistic. Model temporary structures if they form a large part of the construction work (this provides accurate quantities, and if 4D planning is used, it gives a better understanding of the period over which temporary structures are needed. Use the model for visualization during LPS planning meetings to improve understanding of the product and the process. Involve project partners from outside the site as well as site teams in periodic LPS planning meetings, to synchronize the pull of detailed design/fabrication information as well as fabricated components. Ensure that all participants are committed to upgrading their software tools simultaneously.
This summary reflects the synergy between LC and BIM as well as valuable improvements in the processes when implemented simultaneously.
5.3.2 Discussion
The author of this thesis has visited several Finish construction companies on different occasions, but mostly Skanska Finland Oy. Skanska has been studying how to implement LC and BIM in their processes since 2006, and they admit that they are still learning. Considering that it took Toyota around 40 years to develop their Toyota Way, it is understandable that Skanska is still learning. Still, it is good to acknowledge that they have accepted the need for changes and therefore, for studying different new business models that can improve processes.
A Skanska executive has said that it is more important to understand the processes than tangible things. The product is an end result of a series of processes; i.e., inflows have a great impact on
71 workflow in construction projects. Skanska Finland Oy has used LPS to make their workflow more predictable, as LPS is a systematic way of planning. They have acknowledged positive effects on their work, and therefore, Skanskas CEOs have stated that their project people must start using LPS on every project. Sakari Pesonen, executive manager, responsible for implementing lean in Skanska Finland Oy, has stated that construction as a process can be compared to a rowboat, where all the parties involved must stay in one rhythm to be successful. Any variation in rowing can and usually will impact the whole project.
Employees at Skanska have witnessed that using BIM enables leaner processes. Thus they are trying to model as much as possible. They have established a BIM competence centre, where they are daily investigating this field in the matter of software, hardware, and processes, as well as how and when the model can be applied. They use BIM for doing general site planning, and this should allow for a safer working environment and better site organization. In the pre-construction phase they are also using clash detection, 4D, and if necessary, 5D. Clash detection is used to prevent any clashes during the construction stage, where rework and making changes is more expensive. 4D is used to understand if the network of commitments that was created during reversed phase scheduling is realistic or not. 5D is used to understand the flow of money; this is important information for the client, who is planning his resources. There are many more positive aspects of using BIM, but the most important is the visualization. A virtually visualized model is used to coordinate meetings on site, the work of sub- contractors, etc.
BIM competence centre employees stated that the most important part in the matter of using BIM is to understand its process and how people should work together. In the matter of BIM and LC, continuous learning and training of site personnel is definitely a key to success. When considering the Estonian construction industry, then neither BIM nor LC is even in the infancy stage yet. However, many companies have started to show interest in this topic. The main problem with the Estonian construction industry is that we are lacking professionals who could start using BIM and LC in their daily work. This is where universities can help out by educating a new generation of specialists in BIM and LC.
72 5.4 Conclusion
Lean construction and BIM are different initiatives, but both have proved to have a profound impact on construction processes. There is evidence that LC and BIM make better processes possible and when implemented together, allow even better results. IPD, as one example of integrating Lean and BIM, shows that it is possible to manage and run projects in a collaborative and trustworthy environment, where savings are up to 30 % in terms of time and money (Khemlani 2009). It works by breaking down the silos between different stages and including as many project participants as early as possible in the project.
73 CHAPTER 6- CONCLUSION
This chapter draws conclusions based on research, answering the questions posed in the first chapter of this thesis, as well as offering a solution for the Estonian construction industry. The research is not only based on a literature review, but also includes a significant share of empirical research results. The author of this thesis has used his knowledge and experience gained from previous work and from compiling this work to deliver presentations at his university and in several private sector companies. The authors expertise is also being applied in the establishment and development of a BIM Competence Centre at the University of Applied Sciences. It is also worth mentioning that the author of this research is also a founding member of EstGLC, a non-profit organization which organizes seminars, trainee programs, and conferences on LC and related topics.
6.1 Answers to questions
1. What are the main problems connected with construction and what are their causes?
In this research great focus was put on understanding the problems occurring in the construction industry and their causes. On a general level, the author argues that, as many researchers have pointed out, the lack of a specific theory for construction or even a bad implementation of the few existing theories is the root cause for the construction industrys underperformance and insufficiency (Koskela & Howell, 2002). Current theory is based on Transformation theory, instead of TFV, which was suggested by Koskela in 2000. Transformation theory does not give an explicit understanding of construction, which is needed to successfully deliver projects. It neglects the systematic understanding of construction; i.e. where all the processes and stages in project delivery are coherent and influence each other more or less. The biggest cost impacting construction today is that of inefficiencies built
74 into the way projects are run and managed ­ not costs of raw materials like steel and concrete, or the cost of labour (CMAA 2005).
2. Which problems are occurring in the Estonian construction industry?
The second half of chapter two is a summary of the research compiled by the author of this thesis and EstGLC. It focuses on problems and their causes occurring in the Estonian construction industry. The following conclusion has been reached in this study: the Estonian construction industry does not differ much from other countries. The same problems listed according to the literature review, are occurring in the Estonian construction industry as well. Thus, it is beneficial to learn from the experiences of other countries to tackle the problems and address them with new, innovative business models. In this work, the author is offering LC, BIM, and an integration of these two to improve the Estonian construction industrys performance and relatively bad public image. To preclude any misinterpretation, the author does not claim that these are the best or only solutions but believes that these could be the first steps towards better construction project outcomes.
3. What is LC: concept, principles and tools?
LC is an adaptation of Toyota philosophy, principles and methodologies for the construction industry. LC also involves other theories like complexity, systems view and etc. It is management theory, whose purpose is to make workflow predictable by removing variability from the production system and managing people. LC has already proven its validity, which has been achieved by implementing its principles and methodologies; e.g., LPS is a systematic planning methodology including several techniques.
4. What is BIM: concept, process and functionalities?
For many, BIM is still a buzz word as they are not familiar with the BIM concept. BIM is an innovative business model emphasizing construction project prototyping. It makes virtual design and construction planning possible, leading to fewer problems during the execution and maintenance phase. The result of the BIM process is a building information model. The glossary of the BIM
75 Handbook (Eastman, Teicholz, Sacks, Liston, 2008), one of the best-known publication in this field, defines BIM as a verb or adjective phrase to describe tools, processes and technologies that are facilitated by digital, machine-readable documentation about building, its performance, its planning, its construction and later its operation.
5. Can LC and BIM be integrated and what would be the result?
"The Interaction of Lean and Building Information Modelling in Construction" compiled by Sacks, Koskela, Dave and Owen (2009) is a thorough, theoretical and practical literature review for understanding the synergies between LC and BIM. This white paper juxtaposes Lean 16 heuristics/principles with the 8 BIM functionalities/uses to determine if using BIM in construction processes promotes leaner processes. Altogether, 56 interactions were discovered between LC and BIM, including positive and negative connections. For most of these interactions evidence has been found and presented in their article (see also appendix).
6. What is IPD?
The American Institute of Architects (AIA) defines IPD as "a project delivery approach" that integrates people, systems, business structures and practices into a process that collaboratively harnesses the talents and insights of all participants to optimize project results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction (AIA and AIA California Council, 2007).
7. Are LC and BIM applicable to the Estonian construction industry?
Regarding this issue, see also the answers to the first and second questions. Basically, LC and BIM are applicable to the Estonian construction industry, as it has same problems as many other countries all over the world. In other countries, for example Denmark , Finland, England, the US, India, etc., these problems have been addressed by implementing LC and BIM concepts.
76 6.3 Solution for Estonian construction industry
LC and BIM are both new concepts for the Estonian AEC industry, but these concepts promise to bring improvements. The first step is to start educating students at universities, as they are more opened to innovation and secondly, industry professionals, in the matter of new concepts, principles and methodologies. As LC is not as tangible as BIM, then it is better to start with BIM. New curricula should be created which focus on the BIM model, current capabilities and methods, and possible future developments. Secondly, the curricula for educating students in new management theories, principles and tools should be created, in particular, a curriculum for LC.
6.4 Acknowledgment
First of all, I would like to express my greatest gratitude to my research supervisor Rafael Sacks, who guided me throughout my work and Roode Liias for his advice as a second supervisor. I am also indebted to Lauri Koskela, who gave me an opportunity to stay in England and study LC and BIM under him and his research team. I am very grateful to my family and friends for their support over the last years. I would also like to thank lecturers at the University of Applied Science, companies, and everyone who was somehow involved in this research process.
77 6.5 Summary in Estonian
Autor: Ergo Pikas- Civil Engineering student, Faculty of Construction, Tallinn University of Applied Sciences Juhendaja : Rafael Sacks- Dotsent, Tsiviil- ja Keskkonnaehituse Teaduskond, Technion ­ Iisraeli Tehnikainstituut Konsultandid: Roode Liias- Professor ja Dekaan, Ehitusteaduskond , Tallinna Tehnikülikool Teema: ,,Timmitud Ehituse ja Ehitusinfo Modelleerimise integratsioon " Arhiveeritud: Tallinna Tehnikaõrgkool, Ehitusteaduskond
ABSTRAKT
Suures plaanis võib selle uurimustöö jagada kaheks. Esiteks uuritakse, milline on ehitustööstuse hetkeolukord ning teiseks uuritakse uusi esilekerkivaid kontseptsioone, täpsemalt Timmitud Ehitamist (LC) ja Ehitusinfo Modelleerimist (BIM) ning nende kahe integratsiooni.
Ehitustööstuse reputatsioon ei ole hea, sellest tulenevalt analüüsitakse uurimustöö esimeses osas ehitustööstusega seotuid probleeme ja nende põhjuseid. Baseerudes uurimistöös ilmsiks tulnud tulemustele, vajame uusi ja paremaid ärimudeleid nagu LC ja BIM ning/või nende kahe integratsiooni.
Mõlemad, LC ja BIM, on tõestanud, et täiustavad ehitusprotsesse, läbi mille saavutatakse ehitusprojektile seatud eesmärgid ja rohkemgi veel. Samas erinevad teaduslikud ja praktilised juhtumiuuringud näitavad, et algselt eraldiseisvate LCi ja BIMi integreerimisel saavutatakse märkimisväärseid tulemusi. Näiteks käsitletakse viiendas peatükis Integreeritud Projekti Elluviimist (IPD), mis on eksisteeriv vorm integreeritud LCst ja BIMst.
Märksõnad: Timmitud Ehitus (LC), Ehitusinfo Modelleerimine (BIM), ehituse peatöövõtt (DBB), ehituse projekteerimise peatöövõtt (DB), Timmitud Planeerimise Süsteem (LPS), Protsent Plaanist Lõpetatud (PPC), jne (vt ka 1.4)
78 PEATÜKK 2. EHITUSTÖÖSTUSE HETKEOLUKORD
Uurimustöö teises peatükis analüüsitakse ehitustöötuses eksisteerivad probleemid ning nende tekkimise põhjuseid baseerudes kirjandusele ja väliuuringutele.
2.1 Ehitustööstuse probleemid
Uuringud, läbi viidud erinevates riikides, toovad välja sarnaseid ehitusega seotud probleeme. Ehitustööstust iseloomustavad järgmised tunnused (Koskela 1992):
Madal produktiivsus Madal tööohutus Halvad töötingimused Ebapiisav kvaliteet
Stanfordi Ülikool, The Centre for Integrated Facility Engineering eesotsas Paul Teicholzga uurisid Ameerika Ühendriikide ehitustööstuse tööjõu produktiivsust ligikaudu 40 aasta ulatuses võrrelduna teiste tööstussektoritega, täpsemalt 1964-st kuni 2003-ni. Ehitustööstuse produktiivsus on langenud, samal ajal teiste tööstusharude produktiivsus on tõusnud enam kui kaks korda. Uuringu tulemus märgib, et ehitustööstuse tööjõu produktiivsus ühe dollari kohta on vähenenud võrrelduna 60-ga (vt ka pt 2.1).
Ehitustööstust nähakse ka kui raiskavat protsessi. The Construction Industry Institutei (2004) hinnangul on 57% mitte väärtust lisavad tegevused traditsioonilistes ärimudelites ehk raiskamine. Samas teistel mitte-platsi tööstusharudel on see ainult 12%. Peamiseks põhjuseks loetakse nõrka organisatoorset juhtimist: ehitustootmissüsteemi organiseerimine , koostöö ja kommunikatsioon, planeerimine ja kontroll.
National Institute of Standards and Technologyi ja Gallaheri (2004) poolt läbi viidud uuring tõi välja, et ebaefektiivne koostöötalitlusvõime erinevate osapoolte ja süsteemide vahel on peamiseks probleemide allikaks. Täpsemalt, ebaadekvaatne, aeglane või täiesti puudulik infovahetus on peamine 79 põhjus ehitustööstuse madalale produktiivsusele. Näiteks on Eestis ehituse peatöövõtu ettevõtteid, kelle eesmärgiks on kasumi saavutamine vahendeid valimata ehk alltöövõtjate arvelt eirates täpselt eelpool nimetatud põhimõtteid.
Baseerudes kirjandusele on (kokkuvõtlikult) välja toodud ehitustööstuses eksisteerivad probleemid. Seega on oluline uurida ja õppida nende probleemide põhjustajaid ning nende ulatust ja mõju.
2.2 Probleemide põhjused
Paljud probleemid saavad alguse osapoolte ebaprofessionaalsusest: enam tähelepanu pööratakse maksumusele kui kvaliteedile, oskamatus mõista ehitusprojekti kui tervikut , ebakompetentne suhtumine, jne.
2.2.1 Ehitusprojektide ehituskorralduslik ülesehitus
Aja möödudes on ehitised muutunud keerukamaks ja nõudlikumaks ning kasvanud on kliendi ootused ja nõuded. See on pannud aluse ehituse peatöövõtu (DBB) ja ehituse projekteerimise peatöövõtu (DB) tekkimisele. Need on enamkasutatud ehituskorralduslikud mudelid nii Eestis kui mujal maailmas, milledel on omad eelised ja puudused. Kõige suurem puudus ehk on see, et need killustavad ehitusprojekti protsessid eraldiseisvatesse osadesse. DB vähem, kuid samuti, sest ettevõtte siseselt on projekteerimine ja ehitus lahku aetud . Tähendab, et eelprojekti staadiumis pole kaasatud projekteerijat ning projekteerimise staadiumis pole kaasatud ehitajat. Tulemuseks on ebaselged tellija nõuded ja soovid, millele järgneb kehv projektdokumentatsioon, mis omakorda põhjustab ehitusplatsil tööde, tööjõu, ressursside seisakut ja raiskamist.
2.2.2 Ehituse juhtimine
Ehitusejuhtimise teooria on jagatud kaheks: tootmisteooria ja projektijuhtimise teooria. Tootmisteooria omakorda jaguneb kolmeks, Koskela poolt pakutud Transformatsioon -Voog-Väärtuseks (TFV). Traditsiooniline ehitus keskendub ainult Transformatsioon tootmisteooriale. Samal ajal projektijuhtimise teooria koosneb kolmest alakontseptsioonist: planeerimine, teostamine ja
80 kontrollimine. Howell ja Koskela (2004) väidavad, et traditsiooniline projektjuhtimine kannatab järgmiste puuduste all:
Planeerimine ei ole loogiliselt defineeritud ja lühiajalist planeerimist teostatakse kehvasti (baseerub demagoogial) või on sellest üldse loobutud . Töid teostatakse vastavalt plaanidele, kusjuures ei võeta arvesse ehitusprojekti hetkeolukorda, et kas reaalselt töid saab teostada või ei. Timmitud Planeerimise Süsteemis (LPS) tähendab see seda, et ettevaatav planeerimine (lookahead scheduling) on puudulik või on sellest loobutud. Kontrollimist seotakse ainult mõõtmiste ja ümbertegemistega. Ei õpita tundma protsesse endid . LPS kontrollkomponendi, mis lisab võimaluse mõõta ehitustööde produktiivsust.
Need teooriad võisid rahuldada ehitusprojektide elluviimist kümnendeid tagasi, kuid ehitised on muutunud komplektsemaks ja nõudlikumaks, samuti on karmistunud ühiskonna poolt peale surutud standardid. Seega on meil vaja terviklikumat teooriat, mis aitab määratleda eelpool nimetatud probleeme ja põhjusi. Autor pakub, et üks võimalus on Timmitud Ehitamise ning BIMi rakendamine.
2.2.23 Õppimine ja täiustumine
Ehitusprojekt on projektipõhine keskkond, mis on kompleksne ja dünaamiline protsess. Seega on jätkuv õppimine (continuous learning- Kaizen) oluline, et edukalt ellu viia ehitusprojekti. Traditsioonilised juhtimistehnikad ja protsessid on puudulikud, sest neil puudub adekvaatne reaalajas toimiv mõõdikute süsteem, mille alusel hinnata produktiivsust ning sellest tulenevalt analüüsida takistusi ja probleeme. LPS, leiutatud 90-l Ballardi ja Howelli poolt, lisab planeerimisel kontrollkomponendi ehk Protsent Plaanist Lõpetatud (PPC), et reaalajas hinnata ehitusprotsesside produktiivsust. Selle alusel saab adekvaatselt hinnata protsesse, mis on hea ja mis mitte. Saadud tulemusi kasutakse ehitusprotsessid täiustamiseks.
2.2.3 Puudulik IT võimaluste rakendamine
Ühe võimalusena, ehitusetegevuse produktiivsuse tõstmisel, nähakse uute tehnoloogiliste lahenduste rakendamist. Ehitustööstus on oluliselt konservatiivsem kui võrrelda teiste tööstusharudega. Põhjuseid
81 võib olla mitmeid, kuid peamiseks peetakse seda, et ehitustööstus on spetsiifiline ning sellest tulenevalt ei ole võimalik uusi tehnoloogilisi lahendusi rakendada. Vastupidiselt sellele on paljud teadustööd ja juhtumiuuringud tõestanud, et rakendamine on võimalik ja tulemused on olnud positiivsed.
Ühe peamise probleemina nähakse seda, et kasutatakse standardiks muutunud CAD programmides loodud 2D jooniseid. 2D projektdokumentatsiooni koostamine on aldis vigade ja puuduste tekkimisele, sest palju tööd tehakse käsitsi ja erinevate osapoolte poolt (koordineerimise küsimus). Sellest tulenevalt tekivad ootamatud lisakulutused, ajakadu, tülid ning see võib lõppeda kohtuistungitega. Oluline probleem seotud 2D joonistega on see, et kulutatakse märkimisväärne aeg projektdokumentatsiooni ekspertiisile. BIM seevastu võimaldab tuvastada suurt osa eelnimetatud probleemidest (vt ka pt 4.).
2.3 Uurimustöö kokkuvõte läbi viidud Eesti ehituspeatöövõtu ettevõtetes
Uurimustöö näitas, et 64,75% 379-st olid eratellimused ja ülejäänud 32,5% olid avaliku sektori tellimused. 53,5% olid ehituse peatöövõtt ja 38,5% olid ehituse projekteerimise peatöövõtt, millest ülejäänud 8% olid all-peatöövõtt. Seega ehituse peatöövõtt on enamlevinud töövõtu liik, sest et enam tähelepanu pööratakse hinnale kui kvaliteedile ning unustatakse ülejäänud fundamentaalsed väärtused, mida ehitusprojektidelt oodatakse .
Uurisime, milliseid tarkvarasid objektide projektimeeskonnad kasutavad. Enamasti kasutatakse traditsioonilisi tarkvarasid ehk siis Microsofti, AutoCadi, jne tooteid, mida on kasutatud kümnendeid. Samuti näitas uurimustöö, et uusi BIM põhimõtteid toetavaid programme ei kasutata üldse. Seega võib Eesti ehitustööstust pidada samuti konservatiivseks, kuigi püütakse olla juhtiv riik infotehnoloogia valdkonnas.
Uurimustöös käsitleti, et milline on projekti maksumuse ja sellest tulenevalt projektimeeskonna suurus. Midagi üllatavat ei avastatud, kuid tõde on, et mida kallim ja tavaliselt sellest tulenevalt komplektsem on projekt, seda suurem on projektimeeskond. Seega meeskonna komplekteerimisel on oluline osapoolte vaheline usaldus, austus ja sünergia.
82 Põhjused, mis tekitavad ehitusobjektil probleeme ja tööjõu seisakut on ebaadekvaatne projektdokumentatsioon ja halb lühiajaline planeerimine.
Uurimistöö annab mõista, et Eesti ehitustööstus ei erine teiste riikide ehitustööstustest, sest esinevad samad probleemid ja põhjused. Seega peaks olema võimalik õppida teiste riikide kogemustest, kuidas täiustada ehitusprotsesse, isegi kui esineb kultuurilisi erinevusi.
2.4 Kokkuvõte
Uurimustööst ilmneb, et üks peamine põhjus erinevate probleemide tekkimisele on tingitud ebaadekvaatsest ehitusejuhtimise teooriast. Aegade jooksul on ehitusprojektid muutunud komplektsemaks ja nõudlikumaks, paraku pole muutunud juhtimisfilosoofia ja tehnikad. Seega puudulik arusaamine ehituse metafüüsilistest alustest on viinud valede arusaamadeni, kuidas juhtida ja üles ehitada ehitusprojektide protsesse tänapäeval. Sellest tulenevalt on põhjustatud ka teised probleemid ja põhjused nendele probleemidele. Uurimustööst selgus, et Eesti ehitustööstus ei ole erand .
PEATÜKK 3. TIMMITUD EHITUS
LC on püüe adopteerida Toyota filosoofiat ja teisi teoreetilisi aluseid parema ja terviklikuma ehitusjuhtimise teooria loomiseks. Ehitusjuhtimine koosneb kahest teooriast: tootmisteooriast ja projektijuhtimise teooriast. Nüüdseks on sellega tegeletud pea 20 aastat, mille jooksul on loodud LCle korralik teoreetiline alus, millest lähtuvalt on loodud metoodikaid ehk tööriistu, et rakendada teooriat praktikas.
83 3.2 Toyota Tootmissüsteem (TPS)
Toyota Tootmissüsteem (TPS) on juhtimisfilosoofia sellest, kuidas juhtida ja organiseerida tootmisprotsesse. TPS arenes välja aastatel 1948 kuni 1975, mille arendamisega tegeles grupp insenere , keda juhtis Taiichi Ohno. Ta oli raiskamise (Jaapani keeles ,,MUDA") kõige suurem vastane.
Taiichi Ohno võttis üle Henry Fordi töö liinitootmisest (ehk voolfilosoofia) ning kohandas, et vastaks tingimustele, mille seadis olukord peale Teist Maailmasõda. Ta sai aru, et tähtis on tootmissüsteemi paindlikus, mida juhib ,,Pull" põhimõte- tekkis ühe toote vool (one-piece flow). TPS loojad said aru, et on tootmissüsteemi tervik, ehk tähelepanu tuleb pöörata kõigile tootmisetappidele, kaasaarvatud tootearendusele.
Taiichi Ohno ütles (Liker 2004): ,,Kõik, mida me teeme, on see, et me vaatleme seda aega, mis kulub kliendi poolt antud tellimusest kuni raha kättesaamiseni. Me vähendame seda aega viies protsessidest välja mitte-väärtust lisavad raiskamise."
See pani aluse TPS-le, mida teavad ja elavad kõik Toyota töölised ning millest lähtuvalt on nad loonud väärtushinnangud, printsiibid ja metoodikad. TPS on süsteem, kus kõik inimesed hingavad ühes rütmis ja töötatakse ühiste eesmärkide nimel, kusjuures tähtis on iga isiku heaolu ja väärtused.
3.3 Timmitud Ehitamise tootmisfilosoofia
LC baseerub Koskela (2000) poolt pakutud TFV tootmisteooriate integratsioonil, mis baseerub Toyota filosoofial ja 20 sajandil eraldi eksisteerinud kolmel tootmisteoorial. Sellest tulenevalt on pakutud LCi põhieesmärk:
,,LC on arusaamine sellest, kuidas üles ehitada oma tootmissüsteemi nii, et minimeeritakse ressursside raiskamist, et luua maksimaalset väärtust."
LC defineerib , mis on TFV, kusjuures igaüks nendest kattub vähem või rohkem üksteisega. Need kolm tootmissüsteemi põhiväärtust eksisteerivad tootmissektorites ning ka teistes valdkondades. Nende
84 tundmine ja mõistmine paneb aluse printsiipidele ja need omakorda metoodikatele, mida rakendades saavutatakse LCi põhieesmärk, mis peab lisama väärtust mitte ainult kliendile, vaid kogu ühiskonnale.
3.3.2 Timmitud Ehitamise printsiibid
Construction Industy Institute (CII) on välja arendanud ,,Timmitud Ratta" (inglise keeles ,,Lean Wheel") baseerudes põhjalikul ehitustööstuse ja kirjanduse uurimisel (vt ka 3.2). ,,Timmitud Ratas" koosneb viiest pearühmast, millel igaühel neist on hulk alaprintsiipe, kusjuures kõik on omavahel põimunud. Pearühmad eesti keelde tõlgituna on järgmised:
1. Tellija keskne (customer focuse) 2. Kultuur/inimesed (culture/people) 3. Tööruumi standardiseerimine (workplace standardization) 4. Raiskamise elimineerimine (elimination of waste) 5. Jätkuv täiustumine/sisseehitatud kvaliteet (continuous improvement/built-in quality)
3.3.3 Projektijuhtimise teooria ehituses
LC tootmisteooria loob aluse projektijuhtimise teooriale, millega rakendatakse erinevaid metoodikaid ja tehnikaid. Need kaks teooriat on üksteise lahutamatud osad, kus tootmisteooria on arusaamine protsessidest ning projektijuhtimise teooria küsimus on neid protsesse organiseerida, juhtida ja pidevalt täiustada rakendades erinevaid metoodikaid ja tehnikaid. Howell on öelnud: ,,Kõige praktilisem asi on väga hea teooria."
3.3.31 Timmitud Planeerimise Süsteem
Enamtuntud LCi metoodika on LPS, mis on üles ehitatud LCi filosoofiale ja printsiipidele. See on süsteemne tootmissüsteemi planeerimine, mille jooksul läbitakse erinevaid planeerimise etappe ning mille lõpptulemust hinnatakse PPC-ga. Üldiselt keskendub LPS kahele järgnevale eesmärgile: luua sotsiaalne võrgustik ning adekvaatne lühiajaline planeerimine.
85 Howell ja Ballardi lähtepunkt: ,,Kõik plaanid on ennustused ja kõik ennustused on valed!"
Sellest lähtuvalt on nad loonud viis järgmist printsiipi , mis juhivad LPSi :
6. Planeeri seda täpsemalt, mida lähemale jõuad tehtavale tööle 7. Koosta plaanid koostöös nendega, kes reaalselt teevad tööd 8. Avalikusta ja eemalda piirangud tehtavatel töödel koos meeskonnaga 9. Anna usaldusväärseid lubadusi 10. Õpi vigadest
3.4 Kokkuvõte
LC on uus, innovaatiline ehitusjuhtimisteooria, mis on tõestanud kehtivust ka keerukate ehitusprojektide näitel. Ehitusjuhtimine koosneb kahest teooriast: tootmisteooriast ja projektijuhtimise teooriast. See on terviklik arusaamine ehitusprojektides, kust ei puudu korralik filosoofia, printsiibid ja tööriistad, mis aitavad rakendada teooriat praktikas.
PEATÜKK 4. EHITUSINFO MODELLEERIMINE (BIM)
BIM on kontseptsioon , mis nõuab maksimaalset koostöötamist erinevate osapoolte vahel. Paljudele on BIM termin, mida seostatakse 3D mudelitega, kuid see on vale arusaamine tegelikkusest. Seega üks selle peatüki eesmärkidest on lahti mõtestada BIMi kontseptsioon.
4.1 BIM'i definitsioon
Mitmed teoreetikud , praktikud defineerivad BIMi natuke erinevalt, kuid kontseptsioon jääb samaks. ,,BIM Handbook" (2008), üks tuntuim sellealane publikatsioon, defineerib BIMi kui tegevust või omadussõna fraasi iseloomustamaks tööriistu (tarkvaru), protsesse ja tehnoloogiaid , mille tulemusena luuakse digitaalne, masin-loetav dokumentatsioon ehitisest, selle füüsilistest omadustest, parameetritest, funktsioonidest, planeerimisest, ehitusest ja hiljem ka opereerimisest.
86 BIM on innovatiivne protsess, mis võtab luubi alla tervet ehitusprotsessi, planeerimisest kuni lammutamiseni, ning mille resultaadiks on ehitusinfo mudel. BIMi kontseptsiooni toetavaid tarkvarasid iseloomustab võime luua virtuaalseid mudeleid ehitisest, kasutades masin-loetavaid intelligentseid parameetrilisi objekte, mis eksponeerivad selle vormi, funktsioone ja omadusi (Sacks 2004). Seega, mis ei vasta nendele kriteeriumitele, ei ole BIM.
4.3 BIM'i rakendamine
BIMi rakendamise aluseks on võimaluste ja protsesside tundmine ja nendest arusaamine. Seega on väga oluline koolitada ja harida inimesi ning luua vastav BIMi rakendamise plaan, mis aitab mõista protsesse, tegevusi, kohustusi ja ettetulevaid raskusi. Ameerika Ühendriikides on välja lastud vastavasisuline standart , mis kirjeldab neljasammulist protsessi BIMi rakendamise plaani loomiseks. Eesti Kinnisvara AS on tegemas põhimõtteliselt midagi sarnast ning välja on kuulutatud ka esimene ehitusprojekt, kus projekteerija peab rakendama BIMi põhimõtteid.
4.3.13 BIM funktsioonid/kasutusalad
BIMi kõige suurem väärtus on selle funktsioonid ja kasutamisvõimalused ning need loovad võimaluse eelnimetatud tulemuste saavutamiseks. Sacks, Koskela, Dave and Owen (2009) kõrvutasid BIMi funktsioonid LCi printsiipidega, leidmaks, kas nende kahe uue ja innovaatilise ärimudeli vahel on sünergia (vt ka 5.1).
4.4 Kokkuvõte
BIM on innovatsiooniline ärimudel, mis tähtsustab ehitusprojekti prototüübi loomist. See võimaldab virtuaalset projekteerimist ja ehitamise planeerimist, mis vähendab probleemide teket teistes hoone eluea etappides. BIM on palju tõotav kontseptsioon ning autor on veendumusel, et BIM võiks olla esimene samm täiustamaks ehitusprojektide elluviimist. Selleks on vaja hakata koolitama inimesi erasektoris, kus kindlasti vähem tähtsam ei ole vastavate õppekavade loomine kõrgkoolide juurde, et koolitada tudengeid, kes on kindlasti avatumad ja vastuvõtlikumad uudsetele lahendustele.
87 PEATÜKK 5. TIMMITUD EHITUSE JA EHITUSINFO MODELLEERIMISE INTEGRATSIOON
Selle peatüki eesmärgiks ei ole defineerida mingit kindlat töövoolu ja/või kontseptsiooni, et kuidas neid kahte samaaegselt kasutada ja/või integreerida. Pigem uuritakse, kas nende kahe integratsioon on võimalik ning millised on eksisteerivad vormid.
5.1 Teoreetiline taust TE ja BIM integreerimisest
Mõlemad, LC ja BIM, kui kaks eraldi eksisteerivat algatust, on tõestanud, et neil on põhjalik mõju ehitusprotsessidele. Sacks, Koskela, Dave and Owen (2009) viisid läbi põhjaliku uuringu, mis baseerub kirjandusel ja juhtumiuuringutel, et kas nende kahe vahel eksisteerib sünergiat. Teaduslikus artiklis kõrvutasid nad 16 LCi printsiipi 8 BIMi funktsiooniga, leidmaks, kas BIMi kasutamine võimaldab timmitud (leaner) protsesse. Kokku kirjeldati 56 koostoimimise kohta nii positiivseid kui negatiivseid. Enamus nendest on ka leidnud tõestust, mis tähendab seda, et sünergia nende kahe vahel eksisteerib. See on tänuväärt töö, sest selle põhjal on kergesti võimalik hinnata BIMi rakendamise võimalusi LCi protsessides. Samuti rõhutavad ka nemad, et tähtis on mõista mõlema distsipliini kontseptsiooni ning sellest tulenevalt protsesse, et maksimaalset ära kasutada seda sünergiat, mis nende kahe vahel tekib.
5.2 Integreeritud Projekti Elluviimine (IPD)
Projektipõhine juhtimine, nagu on ehitusvaldkond, on kui kolmenurkse kujundi kolm külge: lepingulised suhted, organisatsioon ja opereerimise süsteem. IPD eesmärgiks on adresseerida kõiki neid külgi simultaanselt. The American Institute of Architects (AIA) defineerib IPD järgmiselt: see on projekti elluviimise viis, mis integreerib inimesed, süsteemi, äristruktuurid ja kogemused protsessi, kus üheskoos rakendatakse kõigi osapoolte kompetentsi ja teadmisi nii, et optimeeritakse projekti tulemusi, lisatakse väärtust omanikule, vähendatakse raiskamist ja suurendatakse efektiivsust kõigis projekti etappides (AIA and AIA California Council, 2007). Minimaalselt töötavad koos tellija, projekteerija ja
88 ehitaja, kuid osapoolte arv võib olla suurem ja ulatuda kuni kümneteni, kes kõik kirjutavad alla ühele ja samale lepingule, kus jagatakse riske või kasumit tulenevalt siis projekti edukusest. IPD lõhub piirid erinevate etappide vahel, kus tähtsamaks ja olulisemaks muutub ehitusprojekti projekteerimise algusfaas.
AIA on oma IPD juhendmaterjalis välja toonud 9 printsiipi, mis siis peaksid võimaldama integreerida omavahel kolme kolmnurkse kujundi külge. Opereerimise süsteemi aluseks võetakse LC, kusjuures BIMi käsitletakse ühe tööriistana, mis võimaldab saavutada timmitumaid (leaner) protsesse. IPD hõlmab veel palju teisi metoodikaid ja tehnikaid, üle võetud ühest või teisest valdkonnast. Eksisteerib konkreetseid näiteid, kus on rakendatud või rakendatakse IPD. Üks näide on Shutter Healthi haiglaprojekt (vt ka pt 5), kus tulemused on olnud muljetavaldavad, kõik osapooled on saavutanud oma eesmärgid.
5.3 Empiiriline väliuuring
Selle lõputöö autor koostöös juhendajaga on läbi viinud väliuuringu, mille tulemuseks on Crusell Silla juhtumianalüüs, kus rakendati LCi ja BIMi. See juhtumiuuring läheb ,,BIM Handbooki" teise osasse , mis on üks tuntuim selle valdkonna publitseeringuid. Autor on läbi viinud interdistsiplinaarset õpet, mille raames külastas ehitusettevõtteid ja objekte nii Soomes, Eestis kui Inglismaal.
5.3.1 Crusell Silla juhtumiuuring
Crusell Sild on vantsild, tellinud Helsinki linn ning mis hakkab ühendama Jätkasaari vasakut kallast Ruholahti saarega . Jätkasaaril oli varem Lääne-Sadama osa, mis muudetakse lähimate aastate jooksul mereäärseks luksuselamute rajooniks, kuhu ehitatakse kuni 9000 eramut. See on selle silla tekkimise eelduseks.
Selle projekti raames rakendati LCi printsiipe ja tööriistu ning BIMi tehnoloogiaid. Juhtumiuuringus keskendutakse enamasti ehitusetapile. Virtuaalne mudel pakkus palju eeliseid, mis võimaldas paremat juhtimist ja organiseerimist läbi mille säästeti aega ja raha. Kõigi osapoolte valmisolek ja avatus olid selle projekti eduks BIMi ja LCi rakendamisel ning tänu millele astuti vastu ka kõige suurematele
89 raskustele ja probleemidele. Antti Karjalainen, projekteerija WSP Finlandist ütles: ,,Projekti tulemusi, nii positiivseid kui ka negatiivseid, kasutatakse edaspidiste arendustööde tegemiseks."
Lõpetuseks, olulised õppetunnid, mis avaldusid väliuuringust:
Planeeri BIM ja LPSi kasutamist projekti varajastes staadiumites: sea eesmärgid, vii läbi esmane koolitus ja loo keskkond ning tahe õppida ja areneda. Kasuta mudelit, et toetada ehitusjuhtimise tehnikaid (planeerimiseks, kontrollimiseks, infovahetuseks, koosolekutel , kvaliteedi kontrolliks, jne). Kasuta mudeli sünkroniseerimise võimalust kiireks infovahetuseks. Kasuta 4D, et aru saada, kas kohustuste võrgustik loodud ettevaatavas planeerimise etapis (lookahead scheduling), on reaalne. Modelleeri ajutised konstruktsioonid, kui need moodustavad suure osa ehitustöödest (võimaldab saada täpsemaid mahukokkuvõtteid ja 4D planeerimist). Kasuta mudelit LPS koosolekute visualiseerimiseks, et parandada arusaamist tootest ja protsessidest. Kaasa LPS koosolekutel ka projekteerija, et sünkroniseerida infovoogu ehitusprotsessidega. Kasuta laserskaneerimist, et tõsta töö täpsust ja vältida ümbertegemist. Kindlusta, et kõik osapooled projektis uuendaksid tarkvara samaaegselt.
5.4 Kokkuvõte
Sünergia LCi ja BIMi vahel eksisteerib, mida näitavad erinevad teoreetilised uuringud ja praktilised juhtumid, olgu selleks kas IPD või mõne LCi tehnika ja BIMi integreerimine . Uuringud on näidanud kuni 30%-st kokkuhoidu ajas, rahas ja töös. See juhtub, kuna purustatakse barjäärid erinevate ehitusetappide vahel ning koostööd tehakse teistele alustel, kui seda on tehtud siiamaani.
90 PEATÜKK 6. KOKKUVÕTE
Uurimustöös toodi välja probleemid ning analüüsiti nende tekkimise allikaid . Võimaliku lahendusena pakub uurimustöö välja LCi, BIMi ja nende kahe integratsiooni. Selleks, et neid kahte kombineerida, analüüsiti LCi ja BIMi kõigepealt eraldi ning viiendas peatükis uuriti, kas nende vahel eksisteerib sünergiat.
LCi on terviklik ehitusjuhtimise teooria, mis on tõestanud kehtivust. Ehitusjuhtimise teooria koosneb kahest teooriast, kus aluseks on ehitustootmise teooria ning mida juhitakse projektijuhtimise teoorial baseeruvate meetoditega. See on terviklik arusaamine ehitusprojektides, kust ei puudu korralik filosoofia, printsiibid ja tööriistad, mille alusel rakendatakse teooriat praktikas.
BIM on innovaatiline ärimudel, mis rõhutab ehitusprojekti prototüübi loomist. Võimaldab virtuaalset projekteerimist ja ehitamise planeerimist, mis vähendab probleemide teket ehituse ja kasutamise etapis.
Sünergia LCi ja BIMi vahel eksisteerib, mida näitavad erinevad teoreetilised uuringud kui ka praktilised juhtumid, olgu selleks IPD või mõne LCi tehnika ja BIMi integreerimine. Uuringud on näidanud kuni 30%-st kokkuhoidu ajas, rahas ja töös. See juhtub, kuna purustatakse barjäärid erinevate ehitusetappide vahel ning koostööd tehakse teistel alustel, kui seda on tehtud siiamaani.
Autor on läbi viinud loenguid, seminare ja konverentse, kus inimeste tagasiside on olnud järgnev, et LCi rakendamine Eesti keskkonnas ei ole võimalik ning BIMi rakendamine on kallis. Uurimustööst (vt ka 2.3) selgub , et olenemata riigist ja kultuurilisest taustast on erinevad teoreetilised teadustööd välja toonud samad probleemid ning põhjused neile. Seega, ei saa väita, et Eesti ehitustööstus erineb märkimisväärselt teistest riikidest ning seega peaks olema võimalik õppida teiste riikide kogemustest, et rakendada uusi meetodeid nagu LC, BIM ja nende integratsiooni.
Lõpetuseks autor soovitab , et tuleb hakata looma vastavaid õppekavasid kõrgkoolide juurde, kus õpetatakse uusi, innovaatilisi kontseptsioone nimelt LCi, BIMi ja nende integratsiooni. Alustada tuleks võib-olla tudengitest sellepärast, et nemad on kindlasti vastuvõtlikumad uuele. Kindlasti ei ole
91 vähem olulisem koolitada inimesi ka ehitustööstuses. Esimene samm võiks olla BIM, kuna uurimistöö, mis viidi läbi Eesti peatöövõtu ettevõtete hulgas, näitas, et ei tunta ja ei teata, mida see termin tähendab. Seega tuleb luua õppekavad, mis annavad tudengile ülevaate, mis on BIM ehk selle kontseptsiooni, samuti millised on hetkel eksisteerivad, tuleviku võimalused. Kindlasti võiks koolitada tudengeid kasutama teatud baasprogramme.
6.4 Tänuavaldus
Tahaksin väljendada suurimat tänu Rafael Sacksile, kes juhendas mind lõputöö tegemisel ja Roode Liiast, kes oli lõputöö Eestipoolne konsultant. Olen väga tänulik Lauri Koskelale, kes andis mulle võimaluse viibida Inglismaal ning õppida temalt ja tema teadustööde meeskonnalt LCi ja BIMi. Olen väga tänulik oma perele, kes toetasid mind kõigi nende aastate jooksul ning sõpradele. Samuti tahan tänada Tallinna Tehnikakõrgkooli õppejõudusid, ettevõtteid ja kõiki teisi osapooli, kes olid seotud või kaasatud sellesse uurimustöösse.
92 6.6 Bibliography
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96 APPENDIX 1: CRUSELL BRIDGE CASE STUDY
Note : The Author of this thesis in collaboration with his supervisor Sacks R. conducted an empirical field study and prepared the Crusell Bridge cases study as a part of the second edition of the BIM Handbook
9.8 CRUSELL BRIDGE CASE STUDY .................................................................................................................. 98 9.8.0 INTRODUCTION ................................................................................................................................................ 98 9.8.1 THE CRUSELL BRIDGE PROJECT AS A LEARNING EXPERIENCE ........................................................................ 100 9.8.2 INTEROPERABILITY ........................................................................................................................................ 101 9.8.3 MODEL SYNCHRONIZATION ........................................................................................................................... 102 9.8.4 BIM USE IN THE CONSTRUCTION PHASE ......................................................................................................... 103 9.8.5 SUMMARY, CONCLUSIONS AND LESSONS LEARNED ...................................................................................... 110 ACKNOWLEDGEMENTS FOR CRUSELL BRIDGE CASE STUDY .................................................................................. 110
97 9.8 Crusell Bridge Case study
9.8.0 INTRODUCTION The Crusell Bridge is a cable stayed bridge, commissioned by the City of Helsinki's public works department, which connects the western edge of Jätkasaari with Ruoholahti. Jätkasaari, a part of the former West Harbour near to the city centre of Helsinki, is being transformed into a new maritime urban district. Cargo operations have been moved to another part of the city to make place for development of some 9,000 new dwellings, giving rise to the need for a new road bridge. Figure 9.8.1 shows a rendering of the cable-stayed bridge in its setting in Helsinki harbour. Construction of the Crusell Bridge project began in the Fall of 2008, and completion was scheduled for late 2010. The bridge was designed by WSP Finland and constructed by Skanska Civils. It has two asymmetrical cable-stayed spans, measuring 92.0 m and 51.5 m (the total length is 143.5 m), and has a traffic clearance width of 24.8 m. The superstructure of the bridge is composed of longitudinally pre-stressed concrete beams; the horizontal structure is a composite steel and concrete structure, as illustrated in figures 9.8.2 and 9.8.3.
Fig. 9.8.1 A rendering of the new Crusell Bridge in Helsinki harbour
Fig. 9.8.2 An architectural rendering of bridge deck at night .
98 Fig. 9.8.3 A building model of the bridge structure.
During the design and construction process the project team implemented both BIM technologies and Lean Construction principles and tools. This case study focuses on the construction stage of the project, highlighting two aspects: - The extensive use made of the building information model for fabrication of steel girders and concrete reinforcement, for monitoring and management of the supply chain of fabricated components, for formwork and temporary support structure design, for quality control using laser scanning, and for construction planning using 4D animation. - The ways in which BIM supported lean construction practices, such as its support of production management on- site using the Last Planner SystemTM.
Client: City of Helsinki, Public Width: 24,8 m Works Department Designer: WSP Finland Oy (Inc.) Spans: 92+51,5 m Main Contractor: Skanska Civil Oy (Inc.) Total length: 173,5 m Location: Helsinki, Finland Schedule: Autumn 2008 - Autumn 2010 Type: Cable Stayed bridge Cost: Approx. 15 mil
99 Fig. 9.8.4 Project timeline.
The design for the Crusell bridge was solicited by the City of Helsinki in a design competition announced in the winter of 2001. The competition aimed to find a quality bridge solution that would bring out the characteristics of the area and take into account the requirements of the landscape . Although a British design firm won the competition, the project was awarded to the second place winner , WSP Finland. The second phase of design (design development) was stopped due to financial problems at the end of 2004, at which time 60% of design development had been completed. After a four year hiatus, in 2008 the client assigned its own Construction Management (CMD) Department, a part of the Public Works Department, to publish a tender to find a general contractor (GC) to complete the construction works, and Skanska Civils was selected. As only 60 % of the design was ready at the time, construction works commenced in the autumn of 2008 in parallel with detailed design. Completion was expected in September 2010. The contracting model used was Design-Bid-Build (DBB), which was a little surprising given that only 60 % of the design documentation was complete. However, the rationale was to allow selection of fabricators early, so that they could influence the final stages of design development. The steel fabricator, Rautaruukki Corporation, for example, was involved in completing the design due to their extensive knowledge and experience of steel detailing. This paid off in the long run, as no problems related to the dimensions or quality of steel elements and structures occurred during construction.
9.8.1 THE CRUSELL BRIDGE PROJECT AS A LEARNING EXPERIENCE The Crusell Bridge project became a BIM learning process for everybody involved, even for those who had previous experience using BIM, because many new solutions and techniques were tried. The designer had partially modelled the bridge in order to produce visualizations for the design competition. Because their concept design incorporated a large amount of steel work and had a need for accuracy , they recommended the use of modelling to the client to achieve better results. Thus the client decided to try modelling - and not only modelling of the steel parts, but also all other constructions as well, including cast -in situ concrete structures with all reinforcement. Hence the project became a pilot project for both the client and the designer: for the client, it was its first bridge project using comprehensive BIM, including time and management dimensions, and for the designer, as it was their first experience modelling concrete with reinforcement. Bridge projects are quite different from industrial and housing projects because they have far more complex structures. While the use of computer modelling for structural analysis of bridges was essential and commonplace, the use of BIM for fabrication in bridge projects was not yet as common as its use in building projects. There are few BIM applications that can accurately model the complex structures and geometries that are common in modern bridges. From the point of view of BIM software developers, the bridge design market is of secondary importance. However, as clients, designers and contractors are becoming more interested modelling bridge projects, software developers have begun paying more attention to their needs. At the start of the construction stage, the contractor did not have access to the designer's model, although they knew of its existence. The designer had prepared web models (simple models of the geometry of different parts of the bridge) that the bidders used in tender phase to understand the basic structures of the bridge and to prepare their competitive bids. However, once Skanska was employed, they received the full model that the designer had prepared using Tekla Structures. Skanska made a strategic decision to use model in the construction stage as much as possible, including 4D planning and modelling temporary structures. They had used modelling in housing and industrial construction projects, but using it on a bridge project was new for them too. Using model on site was a new experience also for all of the other parties to the
100 project (sub-contractors, surveyors, suppliers, etc.) as well. As will be seen, the results vindicated Skanska's decision, and they regard the experience gained as highly valuable. Due to the pioneering nature of the use of BIM on a highly sophisticated bridge, the main BIM software provider to the project, Tekla Corporation, was also involved. Providing intensive support to the project team, Tekla too learned a great deal. Throughout the design and construction process they helped the team members learn and then apply new futures of the Tekla Structures modelling software: sharing the model over the web (synchronization); 4D planning; synchronization of the model with suppliers factory management software; and export of fabrication data directly to computer-controlled machinery. Consequently, the project became a unique learning process for all the parties involved. Their willingness to learn new ways of working enabled them to succeed and to accumulate superb experience.
9.8.2 INTEROPERABILITY Table 9.8.1 lists the various engineering software applications that were used through four different project phases: design competition, general design development, final structural design, and construction. The facility maintenance phase is excluded because at the time of writing, the client had not yet decided how to proceed. As can be seen, BIM tools were only introduced during the second part of design development, starting in 2008. Up to the point where design development was interrupted in 2004, each software application functioned as a stand -alone tool. It is interesting to note that the application used for 3D modelling before 2004 was 3D Studio Max, which is a visualization tool, not a parametric object-oriented BIM tool; by the end of the four year break, BIM tools had developed to the point where the design team considered them suitable for a bridge project of this complexity, and Tekla Structures was adopted. An additional factor that explains this progression is that Tekla Structures was, in its earlier versions, primarily a fabrication detailing too, less suitable for early design stages. The challenge of interoperability was not dealt with in the project up to 2004, but after it got under way with additional project partners in 2008, interoperability became a major concern . The first and most obvious way in which this was tackled in the Crusell Bridge project was by all major participants ­ client, designers, general contractor and major subcontractors ­ agreeing to use the same primary BIM tool. Data exchange between these partners was thus reduced to a question of data synchronization, which is discussed later in this case study. Nevertheless, data also had to be exchanged with other applications, such as Trimble Realworks, Vico Control, PERICad, Reinforcement List v3.1 and fabricators' ERP systems. Where this required only geometry exchange, such as between TrimbleWorks and the Tekla model, the DWG file format was used. Where richer information exchange was needed, such as between the Tekla Model and PERICad, IFC files were used. Where alphanumeric data sufficed, or where geometry could be described parametrically rather than explicitly, such as for defining rebar shapes for fabrication, simple ASCII file formats were generated from the Tekla model. These exchanges are shown in figure 9.8.5.
Design WSP Construction Skanska Detailing Ruukki Fabrication and Ruukki Finland Civils delivery scheduling and Skanska Civils
Tekla Structures v13
IFC DWG ASCII
Formwork PERI Construction control Skanska Modelling temporary Skanska Reinforcment Celsa design Gmbh using laser scanning Civils structures and 4D Civils Fabrication Steel planning Services
Tekla Reinforce- PERICad Trimble Structures ment List RealWorks v15 v3.1
Fig. 9.8.5 Information exchange through file transfer.
101 Table 9.8.1. The various BIM and other applications use through different project phases. Application Developer Purpose Design competition phase Integer SuperSTRESS Graitec Preliminary structural analysis ­ 3D frame analysis TASSU T.Palosaari Prestressed concrete beam analysis KATA WSP Detailed structural analysis (2D bending of concrete sections) AutoCAD Autodesk Drawings 3DS MAX Autodesk Modeling, visualization Design development Integer SuperSTRESS Graitec Preliminary structural analysis Lusas Bridge Professional (FEM) Lusas Main structural analysis TASSU T.Palosaari Prestressed concrete beam analysis, stresses and cracking KATA WSP Detailed structure analysis PILG WSP Pile force analysis Tekla Structures v13 Tekla Structural design of abutments and pylon, drawings AutoCAD Autodesk Drawings Final structural design Tekla Structures v13 Tekla General concept of bridge, drawings of the structure Lusas Bridge FEM Lusas Structural analysis AutoCAD Autodesk some drawings MathCad PTC Mathematical analysis, e.g. prestressing and concrete creep Construction Tekla Structures v13 Tekla Basic use on site - viewing of the model, quantity surveying Tekla Structures v15 Tekla 4D simulations and temporary structures PERICad PERI Modeling formworks Reinforcement List v3.1 CELCA Steel service (reinforcement) Trimble RealWorks Trimble Comparing surveying results to design Vico Control Vico Softw. Preparing Master Schedule
9.8.3 MODEL SYNCHRONIZATION Many different participants are involved in every construction project. To improve information exchange and communication between them, Tekla, like other BIM vendors, has developed functionality to synchronize the models maintained by different participants. In Tekla's case, this is achieved using a central vendor synchronization server . The Crusell Bridge project was the first bridge project to employ this functionality. Synchronization was critical for the project, because, as can be seen in Figure 9.8.4, detailed design continued over a long period in parallel with the construction work. This is common not only for fast-track projects, less so for traditional design-bid-build. Synchronization between Skanska's contractor model and Ruukki's fabrication model also proved essential, and this relationship is common in all projects where fabricators undertake fabrication detailing. The client began using the synchronization server later (in Autumn 2009). Synchronization was performed on a weekly basis, but this was not a hard and fast rule. Whenever the designer made significant changes to the model, they informed the site so that they could synchronize to get the latest version of the objects in their model that were inherited from the designer's model (because the contractor also modelled temporary structures, formwork and other features, only the designer's objects that had been changed were added at each iteration, replacing the previous ones. The contractor's project information officer could filter and identify those that had been updated, and see where and how the changes impacted the construction model). In this way, it often happened that the GC had information about the changes in the model well before the drawings were approved by the client, so that they could prepare in advance for the near future (faster exchange of information). Synchronization between the site and subcontractors' models was also done, but on a less regular basis, mainly in response to changes made. The flow of information using synchronization is detailed in figure 9.8.6.
102 Synchronization required not only a technological solution, but also a management protocol , agreed to by all parties, that stated who was allowed to edit what and when. The protocol outlined the following procedure: 1. WPS (designer) uploads design changes to the model synchronization server; 2. Skanska uploads schedule changes to the model synchronization server; 3. Ruukki uploads fabrication changes and schedule updates (dates of order, fabrication, delivery, etc.) to the synchronization server; 4. All participants download ,,change files and import them to synchronize their own models.
Fig. 9.8.6 Information exchange through synchronization.
Enni Laine, Skanska's project information officer at the Crusell Bridge site: "This synchronization practice has been really good. Information exchange has been really transparent and everything has worked very well. Probably a big part of this interoperability and success in synchronization has been dependent on the people. Openness between the teams has probably helped us to learn more about BIM and find out the good practices. Collaboration between different project participants is a crucial factor in successful BIM utilization."
An interesting problem arose with the synchronization during the project. When Skanska upgraded their version of Tekla Structures to v15, it was found that synchronization of rebar data led to anomalies between their model and that of WSP, whose model was compiled and maintained with version 13 of the same package. This limited synchronization to a single direction for a period.
9.8.4 BIM USE IN THE CONSTRUCTION PHASE In this section we describe and discuss the numerous ways in which BIM was used for managing and organizing the construction phase, both directly as an information source and as a supporting technology for lean construction practices. The Crusell Bridge is not large, but has an interesting design and made excellent use of BIM for a number of construction purposes. It is fair to say that the model drove the construction in every aspect. All of the bridge's structure, down to the last reinforcing bar and all of the temporary supporting structures and concrete formwork, was modelled. Skanska maintained the model on a server at the construction site office, and appointed a civil engineer to the role of 'contractor information officer', whose responsibility was to provide information to all project participants and to maintain and update the contractor's model.
103 Why did Skanska maintain the model on site? At the time work began, the design was incomplete, and so the project could not be thoroughly scheduled. Site teams were suspicious at first, not understanding how the model would benefit them, or what they could use it for. But everything was modelled, and the contractor's model was continuously synchronized with the designer's model as it developed. The contractor's model became the primary source for all information for teams on site: for dimensions, for visualizing how to build different parts, for procedures, for material delivery reports, etc. The information officer was kept busy providing all the information requested from the model. Although the initial model of the final bridge product was prepared by the designers, Skanska added to it and edited it to reflect the construction process as well. The model was used a great deal for task and work sequencing, and for viewing work. All of the temporary structures, shoring towers , temporary piles, formwork and equipment ­ were modelled. Carpenters would come to view the model to understand complex geometry before and while preparing formwork for concrete, such as the doubly curved stems of the pylons. Interestingly, due to limitations of the Tekla Structures software version in use at the time, complex double curved geometry could not be generated in the native application. To overcome this difficulty, the geometry of these faces was generated in a different tool and imported into Tekla as reference geometry. This issue has been addressed in newer versions of the Tekla Structures software as a direct result of the company's engagement with the project team; Tekla viewed the Crusell Bridge project as a pilot study for application of the construction management functionality in its software. The following paragraphs detail the different ways in which models were used for construction management, with emphasis on use on site for day to day operations. 9.8.4.1 Visualization Use of building models as a visualization tool is one of its most obvious uses with the clearest advantages. The 3D model of the project helps different parties to better understand the concept and especially the details of the design, forming a common mental picture and understanding far more quickly and effectively than with traditional drawings. The model was made available to all work crews on the job site, and they made extensive use of it, coming to the office view it from time to time to explore the finer details of positioning of formwork, cable anchors and reinforcement. For example, as can be seen in figure 9.8.7, the cable anchors are heavy and they have to be supported before casting . Large quantities of reinforcement were positioned next to the cable anchor . Planning how to support the cable anchor within the forms in preparation for concreting was much easier with the 3D view, which could be manipulated and cross -sectioned in multiple directions.
104 Fig. 9.8.7 Cut section views showing reinforcement details in relation to other cast-in hardware, such as the large cable anchor assemblies.
9.8.4.2 Design and planning of temporary structures and clash detection. Initially, the site crew were provided with many drawings of the formwork, but this did not include the extensive formwork support towers and other temporary structures, such as scaffolding for access. As a result, the site team decided to thoroughly model all the missing temporary structures, including formwork shoring towers and the site tower crane on its tracks, directly in the design building model maintained on site. This provided a better understanding of the structures, enabled identification of numerous collisions (clashes), extraction of accurate quantities, incorporation of these works into construction schedules, and visualization of their sequencing during 4D planning. Clash detection was done not only at the end of the design phase between steel and concrete parts, but also in the construction phase, incorporating additional systems and the temporary structures and formwork. Many clashes in the bridge structure that might only have arisen during construction were thus prevented. This BIM functionality saved a large amount of money and prevented many problems. For example, the formwork supplier, PERI, designed the complex forms for the piers using their in-house CAD system (PERI CAD: http://www.peri.de/ww/en/products/service/software_e/peri_cad_e.cf m). The bridge geometry was first transferred to PERI CAD from Tekla using IFC file exchange, the formwork and support towers were then designed, and finally the formwork models were returned to the construction model, again using IFCs. To the team's surprise, clashes were identified between the bridge cable anchors and the ties between formwork panels on opposite sides of the anchor. The formwork design was changed to resolve the issue (see figure 9.8.8 below).
Fig. 9.8.8 Example of a clash detected between a cable anchor and formwork ties and its resolution.
9.8.4.3 Construction planning and 4D. The building model was first used during overall master planning meetings and then also in reverse phase scheduling meetings, which are a part of the Last Planner SystemTM. VICO ControlTM software was used for the master scheduling, with the model used only for visualization. The master schedule was then imported into the 'task manager' view of the construction model in Tekla Structures v.15, where the schedule was detailed. Deck construction was divided into at least two, and whenever possible three, independent work spaces where work could be performed in parallel, executed by different parties. The model was used to perform this fine-grained level of workspace planning, in terms of spaces, work sequences, quantities and other spatial information. Objects in the model were assigned to construction activities and colour -coded. Figure 9.8.9 shows a section of the deck on a particular date, with two work sections shown marked in red and blue . The 4D video animations of the schedule were done at the resolution of a single day. Thus the team could generate daily visualizations of the project, which enabled assessment whether the decisions made during the reversed phase scheduling stage of the Last Planner SystemTM (LPS) meetings were realistic in terms of their use of space. The animations also gave
105 everybody a better understanding of which works they were agreeing to execute when.
Fig. 9.8.9 Separate work sections, shown colour-coded in red and blue. The model enabled the team to develop more detailed and accurate work plans than they could have achieved otherwise, as it provided accurate spatial information and gave more precise quantities of the materials needed. It proved easy and quick to extract precise material quantity take-offs from the Tekla Structures model, which helped reduce the need for excess buffers of materials and guaranteed that only the necessary materials were ordered from suppliers. However, since association of objects to activities was done manually within the Tekla Structures model, the initial setup was fairly time consuming. After severe engineering problems with the piles of the central pier were identified, the construction work fell some two months behind schedule while new concrete piles were poured to the sea bed to replace defective piles. As a result, the project team decided to reverse the overall sequence of bridge deck construction to allow time for the central pier columns to be rebuilt ­ instead of starting from one end and progressing to the other, passing the central pier in the process, work was commenced from either end and progressed toward the central pier. However, the 4D CAD model was not updated because the time required for re-defining the logical relationships between the detailed tasks, and the relationships between newly-defined tasks with physical objects in the model, was considered to be more costly than the benefit that would have been gained from the process visualization. The uncertainty in the schedule itself was cited as an additional reason for not investing time to update the 4D aspects. The lesson learned from this is that the construction scheduling aspect of the 4D software must be sufficiently sophisticated to allow definition of logical high level task to task type relationships so that construction process changes can be made with the minimum of effort, by changing the rules governing the schedule, rather than by disconnecting and then reconnecting the logical relationships between the detailed tasks. In this way detailed tasks would not have to be redefined and re-associated with physical model objects. At the time, Tekla Structures did not support this level of sophistication in task scheduling.
9.8.4.4 Fabrication and installation of structural steel components The bridge model was shared with the steel fabricator, Rautaruukki, who supplied the project with steel parts and assemblies. Ruukki edited the components in the model as needed to suit their fabrication constraints, and then sent the updated model back to the structural designers at WSP and to Skanska for approval . These exchanges were performed according to the synchronization procedures described above, so that only the objects which they had edited were imported into the other participants' models. In addition to exchanging design information using the model, they also used it to exchange production sequence information in both directions. Since Ruukki had the same model that Skanska had, and synchronizations were performed
106 regularly, Ruukki used the construction schedule data from the model to determine their fabrication and delivery schedule. They then updated the model with their own fabrication, inspection and delivery dates. The internal data transfer, between Ruukki's model and their enterprise resource planning software, was done manually, but they believe that this transfer can be easily automated in the future. Since the construction schedule was updated after each planning meetings and the information was available in the model, procurement of the materials was more accurate, logistics could be organized better, and ultimately delivery and erection of components on site could be 'pulled' using the detailed model information. Erection of the structural steel on site was performed by Siltera, who were employed by Rautaruukki under a subcontract. They did not use the model regularly, but did consult it from time to time to obtain detailed product and process information concerning their work, particularly where drawings were not clear and questions arose.
9.8.4.5 Rebar detailing, fabrication and installation Modelling the bridge reinforcement turned out to be more difficult than was anticipated. Bridges of this type (cable stayed) have a high density of reinforcement and complex deck and abutment shapes, which makes the modelling more difficult and time consuming than for simpler structures. In most common reinforced concrete structures, building elements such as beams, columns and foundations are sufficiently standard in shape and reinforcement details to allow the use of parametric objects and rebar layouts that greatly accelerate modeling; bridge elements have unique geometries due to curvatures, which often require that they, and their reinforcement layouts, be 'custom' modeled . Nevertheless, although the modelling effort was carried by WPS, all project participants benefitted from it. WPS were required to produce rebar detail drawings in any event, as this was still a contractual obligation imposed by the client (for archival purposes and for the use of rebar installers in the field), and the drawings were produced directly from the model. Many spatial conflicts between reinforcement and other structures were prevented at an early stage by using clash detection, and model information was used to drive the rebar bending and cutting machinery. Tekla Structures provides rebar material take-offs in ASCII, EXCEL and other file formats. In the Crusell Bridge project, ASCCI report files were formatted in such a way that they could be imported directly and automatically into the suppliers' rebar fabricating software with all of the information for bending and cutting (See figure 9.8.10). This software drives the NC machinery on the shop floor. The formatting was done in co-operation with the CELSA Steel Services (the rebar fabricator), Skanska and with technical support from Tekla. Naturally, this removed a great amount of human effort and the potential for human error. However, Skanska was unable to achieve the same degree of integration with CELSA as they had achieved with the structural steel supplier, who had the ability to use BIM software itself. The ASCII file exchanges used here were specifically tailored to communicate rebar shapes and quantities, and unable to carry the full range of information that model synchronization would have provided. Some of the information was still exchanged manually. As a result, tasks like bundling of rebar into lots for delivery and installation were scheduled externally to the model. The rebar workflow was as follows: WPS uploads design changes to Skanska's model (WPS detailed all of the rebar, which became the bottleneck activity in the process, so that the flow of rebar detail information was continued over a long time). Skanska selects objects and rebars in the model according to the construction schedule (which was compiled and is maintained in the model); Skanska exports the modified rebar reports (based on ASCII reports) to Celsa; Celsa imports the data into their "Reinforcement List 3.1" package, and the rebar is then fabricated and delivered; Skanska's project information officer prints model ,,snapshots of the rebar cages. The foreman shows these to the workers, who use them with the drawings for assembly.
107 Fig. 9.8.10 Screenshots from the fabricators in-house software for reinforcement fabrication, showing rebar data imported directly from Tekla reports extracted from the bridge model. Rebar was installed on site by Funnly, who only used paper drawings for their work on site. The extremely wet and cold conditions that prevailed on site for most of the construction duration precluded direct use of a laptop or other computer to provide model views at the work face , and Funnly did not have any staff available who could operate modelling software. However, for a number of reasons, the 2D drawings produce by WSP from the model were often inadequate for the rebar installers. As explained above, the bridge reinforcing was dense and complex, and the drawings produced by the standard routines of Tekla Structures v13 were either overwhelmingly detailed or lacking in information. This created friction between the project participants. A number of specific technical lessons were learned and conclusions were conveyed to Tekla for improvement of the automated rebar drawing generation routines in future versions. Partly as a result of their difficulties with the drawings, the rebar installers were sometimes forced to consult the model, which showed every rebar and bolt, to get the complete picture of what was expected and how rebar cages could be tied. The contractor's information officer provided initial BIM training for Funnly, but they remained dependent on her to navigate the model for them and print screenshots when needed. 9.8.4.6 Laser Scanning Skanska, the general contractor, employed a surveyor on site whose task was mainly to control the quality of the work and to assist the trade contractors with positioning their works. Skanska began with equipment borrowed from the distributor , but once they gained experience and confidence with its use in conjunction with BIM, they purchased a Trimble® VXTM Spatial Station for use on site. This machine can capture coordinates, take images, and combine them (see figure 9.8.11); it is a two in one solution, tachymeter and camera . This made the surveyor's work much easier, because he alone could accomplish surveys that previously, with a traditional tachymeter, had required two people. The point clouds and the pictures acquired were uploaded to Trimble RealWorks software, where they were compared with the design location coordinates transferred from the modelling application, Tekla Structures. This enabled real-time quality control for locations of structural components, formwork and hardware embedded in concrete. For example, when placing a large bridge cable anchor, a 1cm difference was identified between the model and real world locations, and so the anchor position as adjusted and checked again before concreting. The information officer taught the surveyor to use the bridge model for his purposes. "Although extracting coordinates from the model was quite complicated, the model was very useful. I got accurate dimensions from it and it helped me to understand what and how must be done if something was unclear during the construction work", he said. The surveyor attended all planning meetings, including the Last Planner weekly work meetings, where he helped determine whether all the technical information needed for completing a candidate task was available or if there were any constraints that remained to be resolved before work could start.
108 Figure 9.8.11 Photograph and scanned point cloud shown together, showing the formwork and piles of abutment T3. 9.8.4.7 BIM Support for the Last Planner SystemTM Skanska Civils Finland had used the Last Planner SystemTM (LPS) in their projects for some three years prior to the Crusell Bridge project, and had their own specialists who train site crews to use it. The LPS can be understood as a mechanism for transforming what SHOULD be done into what CAN be done by working to release constraints on tasks, thus forming an inventory of ready work, from which Weekly Work Plans can formed. It has two main focuses: reliable short term planning, and creation and development of a social system on site (team building, network of commitments, promises and mutual trust and respect). In the Crusell Bridge project they followed traditional planning phases of the LPS, but with some exceptions . The main suppliers and speciality trade contractors all participated in reverse-phase scheduling meetings to plan work 3-5 months ahead. These meetings generated the network of tasks that must be executed, and thus a network of commitments. During the reverse phase scheduling meeting, they used the model to visualize what tasks comprised and how they had to be done. Subsequently, the site manager transferred the results of reverse phase scheduling into the Artemis PlaNet software (a local planning tool akin to MS Project) to clarify and to reconfirm that everybody understood what they were expected to do. The next level of planning was look ahead scheduling. Here they planned three weeks' work by screening each task's constraints and resolving them wherever possible. The look ahead schedule was prepared by Skanska's site crew in co- operation with the subcontractors, after which the tasks were transferred into weekly work plans. The five 'why' technique was used to identify root causes for any tasks that could not be completed despite use of the LPS. This analysis made it easier to remove root causes for delay from the production system. The team only measured the Percent Plan Complete (PPC) over a limited period. The mean value was 84%, but the range was wide , with a standard deviation of 11% . The designers did not participate in the LPS meetings held by the contractor at the site, and indeed rebar detailing became a bottleneck in the process. The project manager thought that 4D planning could have been used more intensively to complement the different planning phases in matters of space use, i.e. to identify collisions or interferences between work units. Designers did not participate in the LPS planning meetings; the project manager suggested that in retrospect, their participation could have been extremely useful, because the sequence of preparation of the detailed drawings, which became a bottleneck activity, could have been pulled by the LPS if they had participated. Site personnel admitted that they have still had a lot to learn about the LPS. Using LPS gave them better understanding of time, flexibility, and the problems that hindered work. It became clear that production problems on site tended to arise
109 whenever sub-contractors missed planning meetings. An additional complication was that subcontractors gave wrong promised dates for task completion, promising to deliver work that couldnt actually be completed by the date promised. In a revealing statement, the project manager expressed the opinion that using LPS in small projects might be too complicated and time consuming. 9.8.5 SUMMARY, CONCLUSIONS AND LESSONS LEARNED Modelling as a virtual representation of reality provided multiple benefits for the parties involved in the Crusell Bridge project. According to all project participants, the intensive use of BIM for construction management enabled better management and organization, and saved time and money. The case excellently illustrates how BIM can be used in a bridge project. The teams' willingness and openness to using BIM and new management methods (LPS) gave all of the parties the opportunity to experience and learn from their own failures as well as from their successes. Much knowledge and experience was gained, which has already found expression in enhancements and improvements made to the delivery processes for future projects. While these methods will become common in complex projects of this kind, there will always of course be problems and the Crusell Bridge was no exception. Given that such use was new for all of the team, it is understandable that obstacles were encountered and problems occurred. The ways the problems were tackled, and the steps taken to remove or mitigate them, were drivers of positive change. Antti Karjalainen from WSP Finland said that, "the project results, both positive and negative, have been used as the basis for bridge BIM development and other software enhancements". Finally, we summarize some key lessons learned during the project: Plan using BIM and LPS from the very beginning of the project: set objectives, conduct initial training and create an environment and willingness for learning and improvement. Use the model to complement construction management techniques (planning, control, information exchange, meetings, quality control, etc.). Use the model synchronization feature to achieve fast information exchanges. Use 4D scheduling to help understand and assess if the network of commitments created during reverse phase scheduling is realistic. Model temporary structures if they form a large part of the construction works (this provides accurate quantities, and if 4D planning is being done, it gives a better understanding of the period over which temporary structures are needed. Use the model for visualization during LPS planning meetings to improve understanding of the product and the process. Involve project partners from outside the site as well as site teams in periodic LPS planning meetings, to synchronize pull of detailed design/fabrication information as well as fabricated components.. Ensure that all participants are committed to upgrading their software tools simultaneously. ACKNOWLEDGEMENTS FOR CRUSELL BRIDGE CASE STUDY This case study was researched and compiled by Rafael Sacks and Ergo Pikas, a civil engineer who graduated recently from the Tallinn University of Applied Sciences and a founder member of the Estonian Group for Lean Construction. The authors are indebted to a number of people who played key roles in the Crusell Bridge Project and took the time to be interviewed and to provide extensive information: Ville Alajoki (City of Helsinki Public Works Department), Antti Karjalainen (WSP Finland), Teemu Nivell (Tekla), Jan Elfving (Skanska) and most of all, the project information officer Enni Laine (Skanska Civils),
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