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The cover of the first edition of Writing Testbenches featured a photograph
of the collapse of the Quebec bridge (the cantilever steel
bridge on the left1) in 1907. The ultimate cause of the collapse was
a major change in the design specification that was not verified. To
save on construction cost, the engineer in charge of the project
increased the span of the bridge from 1600 to 1800 feet, turning the
project into the longest bridge in the world, without recalculating
weights and stresses.
In those days, engineers felt they could span any distances, as ever
longer bridges were being successfully built. But each technology
eventually reaches its limits. Almost 100 years after its completion
in 1918 (after a complete re-design and a second collapse!), the
Quebec bridge is still the longest cantilever bridge in the world.
Even with all of the advances in civil engineering and composite
material, cantilever bridging technology had reached its limits.
You cannot realistically hope to keep applying the same solution to
ever increasing problems. Even an evolving technology has its
limit. Eventually, you will have to face and survive a revolution that
will provide a solution that is faster and cheaper.
经典学习资料英文原版 |
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