Nonlinear Seismic Analysis Of Bridges Using Flexibility-based Beam Element

Refined nonlinear seismic analysis method of bridges has been involved thousands of researchers as long as the theory of seismic is more mature and subtly developed. Compared to nonlinear beam element based on traditional stiffness method, this element which is based on flexibility method has advantages to calculate specified situation. Its element force equation, no matter what situation element is in, is strictly satisfied in the condition of element load is a constant, based on element force interpolation function. From which, sharp nonlinear situation of plastic hinges of element is precisely modeled.Research and analysis delivered in this paper are found on of OPENSEES, which is an open source code seismic analysis program. Frame,element types,data contracture,method of processor of that program is systematically studied, especially the formation of beam-column element based on flexibility method and the determination of element condition. Regulation and the method of the front processor for OPENSEES is concluded, A program using for better front processing is developed by VC++, Whose core language is C++. Then commands in Tcl is written out by VC++to call OPENSEES. At the end of this paper, the project of Xin Kai He is modeled. According to this example, results from time history analysis and pushover analysis using OPENSEE are to find validity and accuracy of element on basis of flexibility method in comparisons. Also, the comparison in the outcome between OPENSEES and Sap2000 to prove the reliability.