[spunkets]

"“pile driving”? What is this term mean? "

It means they'd be pounding in posts into the river bed with a hydraulic hammer. Those posts would be used to support the bridge. Maybe they were for reenforcement, or replacement.

[concretebob]

Most (concrete, H-beam, and shell pile) hammers are diesel...(Delmag, Bucyrus Erie) although sheet pile (Z pile) hammers can be pneumatic or hydraulic vibratory, which also serve a dual purpose as pile extractors.

Looks like the center span broke loose and caused the approach on one side to rock back on its piers.
The bridge looks to be a self-supporting pin and ring suspension. It's designed to flex vertically.