“Looks like a prefab steel span would have been much cheaper and better in retrospect much better....”
no kidding. utterly insane in my opinion to use concrete.
In Colorado, nearly ALL of the modern pedestrian bridges are prefab steel. lighter, cheaper, safer:
Steel needs to be cared for. It needs to be sanded, inspected and painted. I worked on elevated roadways doing just that. I have never heard of tensioning concrete after it is dry enough to put in place.