10-09-2022, 04:23 PM
(10-09-2022, 01:02 PM)gocard14 Wrote: I have to think if it was special forces they would have focused the explosion on the rail side of the bridge to drop the railways for the reasons you’ve mentioned. Maybe that’s not possible with man portable quantities of explosive.It is also a factor of how the bridge is constructed. The rail portion supports a roadbed that has an integral concrete "cap". The roadbed sits on the cap (at least it looks that way, and this is a pretty "standard" approach). This cap is solid reinforced concrete and is pretty rigid. There are I beams under the cap, but the cap holds them in position.
The highway sits on I beams that are mostly held in place by their own weight. Similarly to what happened to the Bay Bridge in Loma Prieta, a lateral shock can dump an entire span, which is what seems to have happened. Obviously, a truck bomb can only explode on the road bridge, but no matter how the explosion happened, road bridges are generally less resilient than rail bridges.