Why are bridges built so high?

Question

I get it if its to avoid rivers overflowing but even then they’re higher than a 2 storey building. What’s the reason for building them like so?

In: Engineering

Answer 1

Things need to be built to deal with the absolutely worst possible outcome. If there’s an extreme flood, then the bridge needs to survive, and potentially still allow people to cross during an emergency.

Also, as someone else pointed out, so that large ships can go under them.