Shaking Table Test For The Effect Of Ground Motion Input To Seismic Response Of Long-span Bridge

With the rapid development of the construction of long-span structures, many new theoretical issues were proposed. Limited to the current knowledge of seismic research and strong earthquake observation, the occurrence of future earthquake and seismic wave propagation couldn't be accurately predicted, hence, large error and uncertainty may exsit in the ground motion input which is the base of seismic analysis of long-span structures. In order to resolve the contradiction between the sophisticated and accurate bridge seismic analysis methods and the relatively coarse model of ground motion input, for providing scientific evidence for the development and improvement of seismic design theories of long-span structures, the researches of ground motion input, which are based on the actual status of long-span structures, are urgently needed to carriey out.In the paper, beginning from theoretical analysis, the basic theories of the ground motion input were introduced, and a few points of ground motion design problem were put forward, several main methods of the artificial generation of seismic ground motion and their advantages and disadvantages are compared and summaried, at last, the current research status of long-span bridges seismic input is proposed.Based on the theoretical research, shaking table test using the advanced vibration equipment of the structural dynamics laboratory (state key laboratory) of Chongqing communication research and design institute is conducted. A 1/50 scale model of the bridge has been made, and then white noise excitation tests and earthquake simulation tests have been done.Meanwhile, comparing with the theoretical results, the internal forces and displacements of the bridge at different ground motion inputs are analyzed, and the effects of the ground motion input to seismic response of long-span bridge and seismic performances of the long-span bridge are concluded.