Sorry to ask this on the board but someone may know the answer.
I come through roadworks on the M60 where they are building several new bridges.
Why do you have the not inconsiderable bulk of a bridge span supported by a small contact patch between the span and the actual upright support of the bridge. The contact patch appears to be about 10% of the top of the upright.
Surely this must concentrate the load on a small area rather than spread the load.
I hope that makes sense from the description.
???
