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Here is how I understand the comment: We have a car bridge designed to withstand exceptional load, and a pedestrian bridge designed to withstand exceptional lo

Here is how I understand the comment: We have a car bridge designed to withstand exceptional load, and a pedestrian bridge designed to withstand exceptional load. The commenter assumes that on average, the car bridge's load is much closer to it's maximum load than the pedestrian bridge's load, and in consequence, the average wear on the car bridge should be higher than on the pedestrian bridge. As such, the pedestrian bridge should have a much longer lifetime, and the commenter assumes that this is the reason old Roman bridges are still standing. Their question is: is this assumption correct?

detrites 3y ago
Sounds good to me, ship it.
bombcar 3y ago
It probably is not correct, because the pedestrian bridge max load is probably something like "what if an idiot drove a car down it" whereas the car bridge max load is "what if it was full of very heavy trucks and one burst into flame". You also have to take failure modes into account, and how degraded the bridge can get before it's "unsafe".