An expert bridge designer has just been on R4 and said that the size of ship wasn't even envisaged when the bridge was opened, the opening was very narrow and there were no protectors around the bases of the supports which are a standard part of bridge design nowadays.
If it is some sort of mechanical failure, there wouldn't be many Bridge supports around the world that would withstand a ship that size/weight hitting them head on
A few things about this as a bridge engineer:This. 100,000+ tonnes travelling at maybe 15 knots ?
The piers clearly aren't able to take an impact anywhere near what they were subject to (that is, the size of the ship isn't really the issue, a smaller ship could have caused a similar collapse).
The electric lines immediately upstream from the bridge have got protection around them, so this isn't a problem they weren't aware of.
Having looked this up earlier today, the design requirement in Europe is project specific, and is based on the idea that the ship will fail first. So in principle it's not a matter of stopping X-thousand tons dead, so much as making sure the ship fails first and the energy is absorbed in the ship crumpling. It's still an enormous force but it's not as absurdly large as might be imagined.
I'm pretty sure that this isn't something any bridges in the UK are subject to, as the supports are either within the river bank or are in such shallow water that no substantial ship could reach them.