Bridges presentation
philosopher, proposed an iron arch of 400ft span over the Schuylkill in Philadelphia. But the next
most outstanding achievement after Coalbrookdale was the cast-iron arch over the River Wear at
Sunderland (UK), because it actually was built. Completed in 1796 by Thomas Wilson, the bridge
had an unprecedented span of 236ft (75m).
Figure 9 Rio Cobre Bridge (1800), Spanish Town,
Jamaica, the oldest iron bridge in the western
hemisphere, was designed by Thomas Wilson and
employs the same iron voussoir, incremental circular
spandrel bracing, and cast-iron plate deck as the earlier
Wearmouth Bridge. Essentially a "kit bridge," the
system of small castings held together by wrought-iron
ties, tubes, and bolts lent itself to export. Many bridges
of this type were shipped to distant colonies of the
British Empire Eric DeLony, photographer
Today, several collections of cast-iron arches survive in different countries, the largest being in the
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