Why would you put concrete above the bridge ??
If they wanted to make a canopy they didn't need it to be that heavy. There is something totally wrong with this foot bridge and look at how wide it is. You could drive a car on that.
https:// www.google.com/imgres?imgurl=https:// upload.wikimedia.org/wikipedia/commons/thumb/5/57/Kerrey_Pedestrian_Bridge.JPG/1200px-Kerrey_Pedestrian_Bridge.JPG&imgrefurl=https:// en.wikipedia.org/wiki/Bob_Kerrey_Pedestrian_Bridge&h=900&w=1200&tbnid=BCnKRkMsB8aLhM:&tbnh=160&tbnw=213&usg=__L2ATCDhCqs5edme8B9eV_jf_tb0%3D&vet=10ahUKEwjn99relO_ZAhUMna0KHSTWB5wQ9QEIKzAA..i&docid=uwWDw9eG0zc9dM&sa=X&ved=0ahUKEwjn99relO_ZAhUMna0KHSTWB5wQ9QEIKzAA
Here is a walking bridge between Nebraska and Iowa. No canopy, especially no canopy made of concrete. I think this is what they should have built. Only smaller.