Parameters in Bridge Restrainer Design for Seismic Retrofit

The primary objective of this study was to determine the effects of changing (1) the cross-sectional area of restrainers; and (2) the restrainer gap on the nonlinear seismic response of a representative bridge with several hinges. The computer program NEABS-86 was used in the nonlinear analyses. The focus of the study was the relative displacements at the hinges, restrainer stresses, and abutment forces. The input earthquake, the number of restrainers at each hinge, the restrainer gap, and the hinge gap were varied. It was found that restrainer forces can become critical in cold weather, when the restrainer gap is minimum. It is recommended that the design should be based on cases with and without restrainer gaps to encompass all the critical forces, stresses, and displacements.