Research On Performance-index And Performance-based Seismic Design Method Of RC Bridge High-pier

American scholar put out the performance-based seismic design theory in theprime of1990s, and the deriving methods get wide range attention of world-widescholars, which is the milestone of structural engineering. As a sign of “buildingsindividuality design” the performance-based design theory make a evolution thattransforming the target of structural seismic design from force-based toperformance-based, and the seismic objective is selected by proprietor. Thereinforcement concrete bridge with high-piers is the critical infrastructure of moderntransportation network in the strategy of “Western Development”, which will occupy amore and more important situation in project lifeline, as the promotion ofdevelop-the-west strategy.But in the earthquake occurred in west area recently, thedamage of high-pier bridge grave threatened our life and money, so the research ofseismic design methods about RC high-pier become one of the hot point in structureengineering. Under this occasion, this paper considered the characteristic of westernbridge in our country research for the performance index and performance-based designmethod of RC bridge high-pier. Overall the major contents are as follow:①On the basis of reviewing a large number of references of domestic and foreigncountry,the development process and research status of the performance-based seismicdesign have been summarized. Considered RC bridge high-pier’s seismic characteristicthis paper put out a reasonable earth hazard level、performance level and performancetarget, as the foundation of the based performance design method for high-pier②Based on OpenSees software platform, the based flexibility method nonlinearfiber beam-column element is used to construct two calculation models of pier with30m and90m hight, which exerted by nonlinear incremental dynamic analysis toresearch the dynamic characteristic of high-pier and making a comparison betweencommon used performance parameter as the material strain、the displacement drift andthe displacement ductility coefficient. Numerical results reveal that the curvatureductility coefficient is better for RC high-piers③Improvements for direct displacement-based seismic design method areproposed, which include two ways: on the one hand, the computational procedure ofyield displacement is modified to consider the characteristic of high-pier; on the otherhand, in order to reflect the actual degree of damage the equivalent displacement ductility coefficient used in the method is deduced from the curvature ductilitycoefficient. Based on the two piers model built before, the improved directdisplacement-based seismic method and the within damage index ductility coefficientmethod are respectively used to design piers’ longitudinal reinforcement ratio andstirrup ratio. After that, the nonlinear dynamic history analysis which is underreasonable earthquake excitation is used to finish the seismic assessment so as to inspectthe improvement of proposed method for RC high-pier.