Quote Originally Posted by Hermod View Post
It costs money. Nothing is free. It will cost one hell of a lot less to put up half a dozen or even a dozen pedestrian bridges than to replace one of the vehicular bridges they are removing. The live load on the pedestrian bridges isn't that much, you are pretty much designing around the dead load.
You know what costs even less? Not proceeding with the damned widening project in the first place. How's that for Value Engineering?

For a pedestrian bridge, you're looking at a live load of 100 psf [[equivalent to the self-weight of an 8" thick concrete slab). That's not my GUESS--that is the minimum requirement of ASCE-7.

Never mind that, at a 60-foot span, you have serious serviceability considerations [[deflections, vibrations). So go ahead--"pretty much" design around the dead load, and see how many people die. Engineering is a freaking piece of cake, right?