The Study On Performance-Based Seismic Design Method Of Beam Bridge973Items:

Seismic design is the only effective means to withstand earthquakes of natural disasters in people’s production practice. For decades seismic fortification purposes gradually shift from a single one guarantying life safety to dual requirements of protecting safety of life and reducing economic losses. Performance-based seismic design theory represents new heights of the current seismic design theory development,which points out the direction for the future seismic design theory research. This paper completely summarizes the content of performance-based seismic design theory framework from five aspects, which includes: seismic fortification level, seismic performance level, seismic performance objectives, structure seismic performance analysis methods and seismic design methods. And among seismic performance analysis methods pushover analysis methods is introduced detailedly, focusing on the principle and implementation steps of the traditional methods and its improved methods.Performance-based seismic design of bridge structures nowadays become a hot research on bridge seismic design. The pier is the main component of a bridge that resists the lateral force subjected to the bridge, therefore the seismic design of pier among the bridge seismic design study should be taken seriously. Numerous studies have mostly concentrated on the directly displacement-based seismic design studies of piers. In this method, the top displacement (the drift rate) of a pier is choosed as the design performance goal. The pier computational cycles can be determined through combining the design performance goal with the displacement response spectrum, and then get on the pier design forces for section design, and check the design pier seismic performance at last. In this paper, the inelastic displacement response spectrum is formed by equal strength ductility spectrum, and in according with the inelastic displacement response spectrum a new design iteration process is proposed, which promotes the engineering application of the equal strength ductility spectrum inseismic design. At last section in this chapter a piler example is designed to examine the design process proposed above.The vertical and horizontal seismic performance of an instance of the pier are analyzed and evaluated from static and dynamic two angles using the improved capacity spectrum method and the incremental dynamic analysis method in the paper with the open source software OpenSees. in four kinds fortification level,the results from the static method is smaller than tieh ones of the dynamic analysis and there is a big difference betwween the vertical and horizontal seismic performance of the pier instances. Utilizing the acceleration time history records selected from PGMD, an incremental dynamic analysis for instance pier is performed, and the pier top displacement IDA curve is obtained; analysis show that the transverse seismic performance of the example pier direction is strong. And the seismic performance of piers with the same cross-section as the original model do parametric study. Through comparison, as the height increases, the pier top displacement increases.