Critical Seismic Issues for Existing Steel Bridges

Keywords: Highway bridges. Hinges. Fasteners. Mathematical models. Ductility.

Abstract: The overall objective of this task was to examine, evaluate, and improve design methodologies for hinge restrainers currently in use by Caltrans and AASHTO. This report addresses hinge restrainers and seat width design for multiple-frame bridges. The authors developed a numerical model to investigate the response of these bridges when subjected to earthquake ground motion, focusing on the longitudinal response of the frames and the hinges. They examined the effects of various dynamic characteristics on the inelastic earthquake response of these types of bridges. On the basis of this analysis, a new, greatly simplified design procedure for hinge restrainers and hinge seat widths was developed and verified by a series of parameter studies and case studies.