Define the Design of Piers and Abutments Erected in Water?

All piers and abutments erected in water are generally designed to be protected from scour or erosion.  However, both stream and structure conditions may undergo changes during the service life of the structure. Exposure or undermining of pier and abutment foundations due to erosion of flowing water can result in the structural failure of a bridge.

When the sediment or rock on which a bridge is supported is lost, the bridge becomes unable to carry the design loads. Partial or full exposure of the foundation footings / or removal of tremie concrete seal can also adversely affect the safety of the structure by causing sliding or lateral movement.  This becomes more critical when vertical movement (settlement) is also present.  The vertical or lateral movement of a pier or pile produces over design stresses, which may ultimately lead to full structural failures.