Vibration of Deck Overhang

[facca]

We are working on a bridge rehab which consists of removing a overhang,abutment & pier joints and replacing with new overhang and making the bridge semi-integral and tied at the pier. The bridge is a steel bathtub girder structure.We placed 40mpa mildly retarded concrete on the overhangs,abutments and pier in one placement.We asked the Owner prior to placement on what to do with the excessive vibration we felt on this structure,the owner was not concerned and we proceeded with our placement.When tapped with a hammer the overhang vertical face sounds delaminated which has been confirmed by coring and observing a vertical crack at the the first layer of rebar.Any insights and thank you for reading this long post.