SEISMIC RESPONSE CHARACTERISTIC AND SIMPLIFIED ESTIMATION METHODS OF TRAFFIC SIGN STRUCTURES ON ELEVATED HIGHWAY BRIDGES

Abstract

 Since the 1995 Hyogoken Nanbu Earthquake, newly constructed bridges of Metropolitan Expressway have been designed or retrofitted to satisfy the required performance against Level 2 seismic motions, and existing bridges have been retrofitted to satisfy it. Therefore, the seismic performance of the bridges has been significantly improved in comparison with the bridges designed before 1995. On the other hand, the seismic performance of secondary systems, which is mounted on highway viaducts such as light poles and utility poles, has not been considered. Damages to their collapse or severe damages would affect both the loss of functionalities by themselves and disturbance of the emergency vehicles. In this study, we carried out an analytical examination with the integrated model of traffic sign structure and highway bridge altogether. From the acquired seismic responses, we examined that the maximum seismic response distribution along the sign pole can be assessed with a simplified estimation method of adoption of floor response spectrum based on interaction effect between traffic sign structure and highway bridge.