APPLICATION OF BUCKLING RESTRAINED DAMPER TO TRUSS BRIDGE FOR BETTER SEISMIC PERFORMANCE

Abstract

The buckling restrained bracing (BRB) is widely used to improve seismic behavior of buildings. It is employed for bridges as well, but the application is very limited. The BRB can be used also as a damper, in which case the device may be called a buckling restrained damper (BRD). Yet such application has not been explored. There are quite a few bridges designed by the old design codes in Japan. Their seismic resistance may not be satisfactory for the current seismic design codes. Against this background, the behavior of a steel truss bridge under a large seismic loading is investigated by the nonlinear dynamic finite element analysis. Some members are indeed found damaged in the earthquake. Retrofit is needed. To this end, the application of the BRD is tried in the present study: a parametric study on the seismic behavior of a steel truss bridge with BRD is conducted by changing the length and the cross-sectional area of the yielding core of the BRD. The study concludes that with the application of well-designed BRDs to appropriate locations, a steel truss bridge could go through a large earthquake without damage.