Baffling how this is ... wrong. I mean it's technically correct, but it's also not. It's like saying the drunk would not have crashed into that building if he took the turn in a different way. It's true ... but it's hardly the cause of something going wrong. You're just pointing out something that could have been done differently.
They did the obvious thing to design the bridge, given that a hangbridge was requested. They started from a standard hang bridge and then eliminated the parts above the bridge itself, realizing that if you can just pull the cables inward the bridge will support itself like a hang bridge would.
But the installable part did not look like a hangbridge, and so the contractor treated it like a non-hangbridge, that only needs support at the sides.
Then, total idiocy struck. They mismeasured. The support could not actually be placed where it was planned when the bridge was designed. It needed to move ~2m to the left. And they did that, put the bridge over it, and left.
So let's go over that last part again. They had a bridge that hung from a pole (the pole was just cut off at a certain point, and a horizontal tension structure put into it's place. Actually pretty cool. Also: despite the article's claims, that definitely works). Then the contractors removed the structure that supported the pole, placing a different support ... at a different place. So they interrupted the foundation of the bridge, making it discontinuous.
(in their defense, with 99.9% of bridges you can do that without causing a problem, which is probably why this mistake was made)
This is like interrupting a building's foundation, and having everything from the 1st floor up supported by a window. The window has some strength, of course, to hold itself up, to hold the side wall up, and generally to not be too easy to destroy, so this will work ... for a short while.
And the of course the predictable thing happens : the bridge breaks in half, at almost exactly the point where the support SHOULD have been, but wasn't ... (and let's just ignore that there would have been loud cracking for a double-digit amount of seconds before the collapse, which clearly was not judged a good reason for the contractors to stop what they were doing).
Who's at fault ? Well the original mistake is mismeasuring where the support should have been. I would not place blame on the designer, because he was working from faulty data. And yes, there were some different designs that would not have had this problem, but the sponsor explicitly asked for this design. Then there were a LOT of opportunities to detect this mistake, all of which were missed. And then there is the fatal decision, made by the contractors installing the bridge as far as I can tell. Oh we can't place the support here, let's just move it a bit. What could go wrong ? And they did move it. Then the bridge showed obvious signs of stress (cracks), right in front of them. Again, somehow this was missed (despite camera footage showing some worker pointing it out to some guy that looks important). They ignored those signs and just left after cleaning things up.
And then ... tiny little shock overloads the weak component (which is the concrete surrounding that cable/beam thing they show, obviously NOT that cable itself). And boom.
If you analyze the blame, it seems like somebody really wants the contractor's decision to just place the bridge on different supports (which, again, is not a problem with 99.9% of bridges) to be the right call. If you force that decision to be reasonable, then there's little choice but to blame the design for not allowing for that. It seems unlikely in the extreme that the design firm hadn't warned the contractors about this though.
