Research On Seismic Finite Element Simulation Method Of Column Slab Piers

With the implementation of the strategy of western development and poverty alleviation,the railway construction in the western region is increasing day by day.Because of the steep terrain in the western region,long-span bridges with high piers are widely used.Meanwhile,the northwestern and southwestern zones in China belong to high intensity earthquake area,so the seismic performance of high piers has become the focus of design and research.For the disadvantages of traditional high pier,such as large volume,uncertain plastic hinge and so on,scholars at home and abroad have proposed a variety of new high pier structures with different cross-section types.A new type of column plate hollow high pier has been used in the Zongmugou super large bridge of Huang-Han-Hou railway,the structure uses the advantages of seismic shear wall for reference.The main frame structure is composed of frame pier column and beam,and the frame pier column is connected by thin-walled reinforced concrete slab.The thin-walled plate can not only improve the stiffness of the pier to ensure the requirements of the railway for the stiffness of the pier,but also can crack and destroy under the rare earthquake action,which makes the overall stiffness of the structure decrease,thus prolonging the period of the structure and dissipating more seismic energy,so as to achieve the effect of protecting the main structure from greater damage under the rare earthquake.In this paper,the longitudinal bridge is taken as the research object,and the finite element numerical simulation method of column plate pier is studied.The main work is as follows:(1)According to the similarity principle,the numerical models of the four components of the main pier section,namely,the transverse column plate,the frame,the longitudinal column plate and the frame can be established.The seismic performance of ABAQUS software is used to study its hysteretic characteristics,stiffness degradation and failure characteristics under the action of the reciprocating load.The results are in good agreement with the test results.The results show that under the horizontal reciprocating load,the circular hole cracks first,which is inclined 45? shear failure,and forms a failure channel along the vertical direction of the ventilation hole.The frame column belongs to bending failure and the column plate structure belongs to bending shear failure.Increasing the width of the plate can improve the bearing capacity of the column plate structure.(2)In this paper,the calculation of the slab between columns is simplified,and the layered shell element is used to simulate the slab between columns.The seismic performanceof hysteretic curve,skeleton curve,stiffness degradation curve and so on are analyzed by comparing the solid element model with layered shell element and beam column element model.The results indicate that the solid model is in good agreement with the simplified model of layered shell element and beam column element,which proves the applicability of layered shell element in the calculation of slab shear wall between columns.(3)The beam column and layered shell elements are used to establish the model of the bridge,and OpenSees is used to analyze its nonlinear seismic response.The results reveal that the simulation results of layered shell element are good,and the simulation method of layered shell element to column plate structure is confirmed,which provides valuable reference for the calculation of column plate structure.