Skyway Bridge Construction

[canoe_gurl]

Hello everyone (wow it has been a long time since I have posted, sorry!!)

A friend of mine is doing a research project for a structural engineering course, and he is having trouble finding out information about the construction of the 2 bridges. He is looking specifically for more information about the structure itself, apprently the one bridge is a hollowed bridge type so that workers can access various parts from underneath? I am not familiar with this sort of thing at all, I just said I would ask around on here to see if anyone knows. Any help would be greatly appreciated!