Ok, you have a bridge pillar holding up a bridge in the water. If you’re lucky you can get thebase of the pillar or drive pilings down to bedrock. In many case it’s simply too deep and it’s just river muck or sand a long way dowm. So the you have to support base of the pillar with a ton of pillings driven deep and angled, etc. They usually try to then pile “rip rap” (boulders) around the bases of tbe brige pillars underwater.
Bridge supports constrict water flow - especially in floods. You get water just screaming through at high velocity. It will erode away the sand or muck around the base of the bride pillar, undercut it, esp. if you don’t keep checking with divers and adding more boulders and stuff. Eventually, so much sand and mud gets scoured out the pillar is unstable and collapses.
Not saying it happened here but it’s one of a variety of ways a brige can spontaneously collapse.
Only one tiny little problem: This bridge did not have any pillars in the water!
The pillars are on ground, not under the river. See pics upthread.
Thank you for the great explanation. That was beneficial to me. I’m tired of reading all the other posts about all the other possibilities, so I thought I would try to get true data on the bridge, depth, etc.
Thanks for the input. I, for one, appreciate it. :)
Except this bridge does not have any piers in the water.