Seismic response of highway viaducts equipped with lead-rubber bearings under low temperature

Abstract

Based on a FEM based nonlinear dynamic numerical method, this study investigates the detrimental effects of low temperature on the seismic responses of a highway viaduct equipped with Lead-Rubber Bearings (LRBs). In this method, a dynamic bearing property definition is introduced to account for the temperature variation caused by the absorbed earthquake energy and the corresponding property variation of LRBs. Under low temperature conditions, the base isolation effect of LRBs which are well-designed for room temperature is significantly weakened, manifested by shorter fundamental structural natural periods and more damages and forces imposed to structure members, such as a 5–13% increment of shear force transferred by the LRBs, an increasing area of the hysteresis loop of the bending moment at the bottom of piers, and an increasing residual displacement at the top of piers. In addition, through jointed investigating the seismic responses under both long and short durations of earthquake motions, it is demonstrated that the heat production in LRBs over an earthquake can alleviate the detrimental effect of low temperature, and the extent of this alleviation is positively correlated to the earthquake duration. Therefore, the low temperature effect and the property variation of LRBs over an earthquake should be comprehensively considered for the designation of LRBs installed in bridge viaducts located in cold regions and the realization of an accurate seismic analysis of the bridge viaducts.