A new design strategy for seismic safety in super earthquakes of continuous girder bridges

Abstract

Abstract In recent years, devastating earthquakes have occurred all over the world, and the huge seismic damage of lifeline engineering structures would cause great personnel casualties and property loss. In order to guarantee the seismic safety of lifeline engineering structures, usually two seismic hazard levels, for instance Design Earthquake and Maximum Considered Earthquake are considered in most seismic design codes. However, several disastrous earthquakes have proved that seismic safety evaluation may underestimate seismic risks, which would result in serious damage of lifeline engineering structures. Therefore, another higher level of seismic hazard named Super Earthquake is proposed to be considered in this paper for very important lifeline engineering structures. To improve the seismic performance and meet seismic requirements of Super Earthquake, a new design strategy for seismic safety is proposed at first based on deep learning. In the proposed strategy, rigid blocks are combined with common seismic isolation bearings and expansion bearings and two new kinds of bearings are developed. Taking two continuous girder bridges as numerical analysis examples, the proposed strategy is compared with two other seismic design strategies adopted in current seismic codes and parametric analyses are conducted. It’s shown that the proposed strategy can combine the ductility capacities of piers and the functions of seismic isolation bearings and reduce all the concerned structural seismic responses in Super Earthquakes effectively.