STUDY ON SEISMIC DUCTILITY IMPROVEMENT FOR EXISTING MEMBER OF STEEL BRIDGE

Abstract

 As seismic retrofit method against a Level-2 ground motion for an existing sway bracing and lower lateral bracing of upper-deck type steel arch bridge, an efficient retrofitting method by energy absorption had been proposed to prevent these buckling. In this study, these performance confirmation experiments and FEM analyses were conducted. As a result, a global buckling of the member was restrained by proposed retrofitting method of ductility improvement type, and it was satisfied with the deformability of the required performance on the design. It became clear that an energy absorption by axial strain can be expected beyond yield strain from the early stage over the whole axial member. Also, the experimental result was reproduced by the FEM analysis considered with the contact phenomenon between the existing steel bracing and the steel restraint member.