Why the Baltimore bridge collapsed so quicklyA little Engineering tl;dr.
Every bridge, and most buildings, are falling. All the time. But the fall is just stopped by their construction. Cables, girders, supports all delay that fall and give it the ability to hold some weight. But only a limited weight. If you remove any of the things that keep it up, it will come down because the rest of the bridge or building is not strong enough to compensate for the increased load. You can have a bridge that is robust and will tolerate a little failure, or you can have one that a state can afford on it's infrastructure budget.
CKA Moderator 
CKA Moderator 
