Here we go again: I-5 bridge over Skagit River (Washington) collapses; cars in water

[madokie]

77. Each section is a unit

so yes a hit to a part of that section could cause the whole unit to collapse. What I'm saying is that is a truss and every single part of that truss is vital to the well being of the whole truss. I'm not saying that when they investigate they don't find that it was about to fall anyway although I doubt that will be the case. I've been around enough structures to know that yes taking out one part of something can cause the whole things to collapse. the bigger and heavier that is the more that is true too. The part that the trucks load hit is a vital part as all parts to a truss is and that bridge is a series of trusses. one after the other setting on the concrete structures that are anchored to and setting on the world under the water in the river.

Sure its past its designed lifetime but that doesn't immediately mean it will collapse any day. If its structurally deficient yes it will fall but these things are inspected quiet regularly. The trucks load hit the bridge and that is what brought it down, thats fact.