DESIGN EARTHQUAKE AND DAMAGE CONTROLLED STRUCTURE IN SEISMIC RETROFIT OF A LONG-SPAN TRUSS BRIDGE

Abstract

A long-span truss bridge with 980 m long, is located in the Hanshin Expressway near Osaka port and has seismic risk which cause failure to not a few main members due to scenario level II earthquakes. In this project, a damage controlled design concept is employed to achieve rational retrofit from a view of risk management. The concept differentiates main members that support vertical load from sub-members for lateral force such as seismic force. According to this design, main members should be liner and sub-members are allowed to perform nonliner and provide damping. In this paper, floor seismic isolation system and buckling restrained brace system are introduced based on the design concept and their response reduction effects are also described.