| Because of the particularity of topography,railway hollow high pier bridges have been widely used in mountainous areas in Western China.However,the traditional hollow railway high pier is restricted by the stiffness condition,the masonry capacity is large,the cross section of hollow high pier is larger,and the restraint effect of stirrups will be weakened significantly.The ductility and energy dissipation of bridge piers and plastic hinges with uncertain positions can not be brought into play effectively when earthquake occurs.In order to solve many disadvantages of traditional hollow high piers,various kinds of new type high pier structures with different section have been put forward at home and abroad.By summarizing the research of high piers at works.For the first time,a new type of hollow column slab pier has been adopted by Chinese designers.In order to understand the seismic performance and numerical calculation method of this kind of piers,the main research work of dissertation is as follows:(1)Based on the similarity principle,8 speciments of 3 category,1:10 model members are made,including the transverse bridge column slab,the longitudinal bridge column slab and the longitudinal bridge frame of the new type column slab high piers in the actual engineering structure.The failure mechanism,hysteretic characteristic and stiffness degradation are studied by quasi-static test method.(2)The solid model of the transverse bridge to the column slab member,the transverse bridge to the frame column member,the longitudinal bridge to the column slab member and the longitudinal bridge to the frame column member is established by using the finite element software.The seismic performance of the system is simulated by the same loading system as the pseudo-static test.The ductility and deformation capacity of column slab structure are studied from the aspects of hysteretic curve shape,the equivalent viscous damping coefficient,the energy dissipation coefficient and the stiffness degradation,and the test results of the pseudo-static are compared and analyzed.(3)The nonlinear characteristics of the inter-column slab were simulated by two spring element model.According to the geometric parameters of the structure,the two spring element model parameter calculation is numerically simulated,and the two spring element model parameter calculation formula suitable for the column slab structure is established.The validity of the modified two spring element model parameter calculation method is verified by the solid numerical simulation calculation and the pseudo-static test results,and a simplified numerical simulation method for the nonlinear seismic response analysis of the column slab component is established.(4)In this paper,the finite element model is used to analyze and study the seismic response of the new type column slab high piers bridge under the action of frequent groundmotions,and the key parts of the stress of the bridge under earthquake action are determined.It provides the basis for the selection of the key parts in the analysis of the rare earthquake response of the whole bridge.(5)The modified two spring element model is used to simulate the main pier column slab,and the seismic analysis model of the whole bridge model is established.Nonlinear seismic response analysis of he new type column slab high piers bridge is carried out to study the seismic performance and seismic response characteristics of the new type of column slab pier.The results show that the structure can effectively protect the pier column and prolong the period of the structure through the damage loss of the inter-column slab under strong earthquake.The distribution of internal force and displacement of this new type of hollow high pier under seismic action is significantly different from that of conventional piers.The location of peak value of internal force and displacement of pier is related to the input direction of the ground motion. |
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