I honestly don't fucking get it. The article just says "it wasn't an accident" and leaves it at that?
I do know lots of corners are cut by companies vying to get the contract, knowing it can't be done at that price or even double. I565 in H'ville AL, a section of that interstate was supposed to have 80' pilings but the company got caught installing 40' pilings. I can't remember what all came of it, but this shit does happen. And no, in that case it's not an accident, it's intentionally done for greed and greed alone. And because they figure they can get away with it.
Usually when a company only puts in half the pilings someone is getting paid off.
If you look at the pictures of the bridge,you'll see where they went in and hammered the deck through in between the beams.
What I think happened is this.
The operator hammered out two decks and when he was walking the machine off the structure he slid the first deck off the peir.
( It happens believe me )
On a structure that uses steel for the girders instead of post-tension you normally saw cut the deck and strip it with an excavator.
With Post-tension construction the deck becomes a monolithic structure therefore you have to hammer out between the beams.
Something people don't realize is that bridge is just resting on top of the peirs,there is nothing holding it down except weigth.
When you take the deck off,the whole structure can rack and down you go.
I have stripped many decks off bridges and they are very very dangerous to say the least
I remember sitting on the Veterans memorial bridge in Cleveland back in the 90's and have the wind blow my 60 ton machine around because ice formed under the my tracks.
When we did I-90 bridge that was tricky,everything was rotten.
BTW- they got lucky as hell, because when that deck slid it could have very well started a domino effect.
You may not think it,but it's all relative, bridges are a balancing house of cards.