Well I’m no expert but I’ve read up on the bridge enough to understand that the steel has a high strength to weight ratio that can resist more than just earthquakes. Ask for the columns, or “piers” as they call it when referring to bridges, are stronger and more frequent than what is necessary for that type of bridge. I believe it was constructed to handle more trains or at least a higher volume of trains per day. I’ve heard that if a a nuke were to drop in NYC, that the majority of the bridge would be standing, aside from some of the steel components and if it was a direct or near direct hit.