It doesn't look like there is any sign of an explosion and that is about the only way a terrorist could do this. I looks to me like structural failure.
Explosives only have to be placed on the supports and the ongoing construction would be great cover to place the explosives. Wouldn’t be able to see evidence of that, as it would be covered by the bridge. Fox reporting eyewitness accounts of explosions/things exploding.
wagglebee, I wanna know who the cement dealer was.