Progressive Collapse Analysis Of Pile Group System Bridge Using Open Sees

Group pile foundation is the basis of the most commonly used in bridge construction of our country, especially in the high pile is widely used in high-rise pile cap, which has small settlement, short construction period, and the advantages of adaptability, but according to the earthquake disaster investigation, under seismic action the group pile foundation is the vulnerable component of the structure, bridge pile system is widely used in the irregular bridge structure, the traditional design method has already can’t adapt to the rapid development of performance-based structure design theory, the paper discusses that the failure mode of pile foundation under earthquake action and failure regularity and damage development is the need of current bridge seismic analysis, and continuous collapse analysis of bridge structure under seismic action is a very complicated problem, most commercial programs exist the difficulty of numerical simulation in the collapse analysis.Based on the platform of OpenSees self-programming, the paper simulates continuous collapse behavior of pile foundation, and establishes the failure criterion of bar, detailedly analyzes the model of the Remove command updates. the Remove command can handle large deformation and large rotation of the structure, and realize the simulation of structure collapse, then solve the traditional finite element numerical solving the difficulties. The paper adopts the nonlinear beam-column elements of OpenSees to construct the structure nonlinear beam-column elements constructed with affiliated node to simulate bridges, constraint condition of attached node is adopted the method of multi-point constraints handling, adopts the method of static condensation, and the correctness of this method is verified by calculation. The paper detailedly analyzes the failure mode of pile group foundation under the action of the earthquake and a detailed study of the treatment methods, introduce bending failure criterion, shear and axial failure criterion, by real-time monitoring, structure analysis of the failure unit the end of the constraint condition of real-time processing and change the structural analysis model. Containing group pile foundation has been established based on a practical project of single pier model, select a set of 2 kinds of site seismic analysis of continuous collapsed, simulates the internal force of the pile foundation of the release and gradual failure process, and completes after undermine delete link and update the model, the residual seismic response analysis of the finite element model.The structure model of real-time modification of reaction components can reflect the progressive failure process and the process of progressive collapse under the action of earthquake, the failure process of the structure will increase the release of internal force that under the action of earthquake, which is principal element of the collapse of the failure mechanism of pile group foundation, collapse mode, and the integral structure damage evolution law.