An overview of guidelines and requirements for seismic design of new bridges and retrofit of existing ones in New Jersey is presented. The results of an ongoing study on seismic assessment of existing bridges in New Jersey are also presented. It is shown that for many older bridges the seismic capacity in the transverse direction is minimal and the bearings can be damaged. However, because of the redundancy of multigirder bridges, failure of the bearings may not cause collapse of the bridge as long as the columns and piers possess adequate ductility and strength. Circular columns do have adequate lateral reinforcement, but square columns lack the needed ductility demand. In the longitudinal direction, again, failure of the bearings because of shear failure of the bolts is a strong possibility. Unlike in the transverse direction, because of impact and separation of adjacent spans and inadequacy of seat width at the abutments and the tops of piers, loss of span and total failure of the bridge can occur. Therefore, it is important that essential bridges be retrofitted in the longitudinal direction, as proposed. Future research and development needs are also discussed.
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering
- Mechanical Engineering