[adameasterling]

> Everyone being surprised at the bridge collapsing needs to reconcile with the amount of force that struck the bridge ... I am also a bit surprised at how many people don't grasp this or grasp engineering, magnitude of forces and design principles.

A spokesman for CalTrans claimed today that Bay Bridge could have taken the same hit without damage, thanks to fenders that protects all pylons for all bridges in the San Francisco Bay Area (1). Cargo ships are heavy, yes, but it appears we have the technology to prevent bridge collapses due to these sorts of collisions today.

1. "The Bay Bridge’s fenders insulated the span during the 2007 incident, so that the Cosco Busan ship struck a bumper, never hitting the bridge itself, Ney said. He noted that fenders on Bay Area bridges should be able to handle a ship traveling at 8 knots, the velocity at which the ship hit the Francis Scott Key span."

https://www.sfchronicle.com/bayarea/article/baltimore-bridge...

[quasarj]

"A ship traveling at 8 knots" is a meaningless statement. You need to know how bit the ship is...

[saulrh]

Thanks to things like planetwide bottlenecks through specific canals and locks and design of certain ports, approximately all container ships are within a couple meters of one of only a handful of size buckets, several of which are fairly close to each other besides. For example, a large fraction of the world's container ships are sized to be within a meter of fitting into chinese port facilities and the suez or panama canals. Because these dimensions include the depth of the water as well as the length and width of the ship they also limit the total volume of water which is available to be displaced, which puts a limit on the total mass that can be floated. As a result, "a container ship" is actually a fairly tight and predictable specification of a ship's maximum mass!

[MOARDONGZPLZ]

Container ship

[boringg]

That may be so and I appreciate CalTrans confidence in the matter. I however would never want a similar set of circumstances to strike the bay bridge and have to test it.

It is a very different bridge design (assuming were talking about the Oakland to treasure island portion) and it is built in earthquake country.

I'm not saying there shouldn't have been fenders or other protective measures. I'm saying that the amount of force on a direct hit that STOPPED that the ship dead in its tracks - that bridge was not going to withstand it and I do question what would happen to the bay bridge. Again I appreciate the confidence of CalTrans to reassure the commuters but I have seen government officials express too much confidence before.