Bridges presentation
Pont Neuf (1607) in Paris. These bridges, which are among the most famous bridges in the world
today, are all on the World Heritage List, although only as components of historic town centre
inscriptions. Renaissance engineers had learned much about foundations since Roman times, though
they rarely were able to excavate deeply enough to reach hard strata. They had, however, perfected
techniques of spread footings - wide timber grillages resting on piles driven into the river bed upon
which stone piers were laid. In the foundation of the Rialto Bridge, designer Antonio da Ponte drove
six thousand timber piles, capped by three stepped grillages so that the abutment stones could be laid
perpendicular to the thrust lines of the arch. Though built on soft alluvial soils, the bridge continues
to support a street of jewellery shops enjoyed by tourists four centuries later.
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