ABSTRACT
In the present seismic design of bridge structures, the ground motions are generally used to carry out nonlinear time-history response analyzes. As the selected ground motions will affect the nonlinear time-history response of the structure, it is crucial for the seismic design to select or generate ground motions close to the site response spectrum. There are three ways to select the time histories of accelerations of the ground motions at present: 1) direct application of the strong motion earthquake record; 2) synthetic time histories of ground accelerations; 3) standardized time histories of ground accelerations. In general, the chosen should be the priority and preliminary field seismic record of similar geological conditions. However, due to the limited records, synthetic ground motions, and standardized ground motions are more widely used. Of the latter two ground motions, standardized ground motions which are provided by corresponding specifications have not been used in China. As a result, synthetic time-history ground accelerations given by the seismic safety evaluation reports of the sites of bridges have been used. In the seismic safety evaluation reports from the construction site, it is necessary to provide the timehistory ground accelerations that fit the design response spectra and meet the requirement of the seismic design.
