Phila Chestnut Street Bridge01
Chestnut Street Bridge, looking downstream from the Market Street Bridge
Photo taken by D. Thomsen
BH Photo #172480
My guess would be that it is a 1957 bridge on a substructure that is partly composed of 1912 stone piers and abutments from a previous bridge. If you look at the pier, there seems to be a combination of stone and concrete.