Podium Area And Tower Location To The Building Effect Of Seismic Performance

At present,China’s urban construction land is scarce.The structural system configuration of large chassis tower is reasonable.Its use functions are more diversified.And the land utilization rate is higher and higher.So,this structure has been used in commercial complexes and other building systems widely.The thesis concludes some relevant theories about the tower structure with large chassis.There is a simplified model in Xinyang,which is an office building.It is taken as the research object of the single-tower structure with large chassis.In this study,the podium’s area change and the tower’s position change in the podium are taken as variables.The purpose is to explore the influence of the podium on the seismic performance of the tower.This thesis summarizes the development of seismic theory,describes the features of shape structure and the seismic performance.Besides,it also concludes the the calculation and analysis model and vibration calculation and derivation of tower structure with large chassis.Moreover,this thesis proposes some suggestions about the design modeling and analysis principles of this kind of structure.The thesis’ main research contents are presented as follows:(1)First,in order to study the tower’s influence on the stress distribution of the surrounding podium,the ANSYS finite element software is used under the horizontal earthquake.The calculation results show that the influence of the tower on the podium is obvious in the two spans around it.The influence of the tower on the podium is different.In the first span,it attenuates 70-80%.In the second span,it attenuates20-30%.(2)Then,under horizontal earthquake,the PKPM is used to analyze the influence of podium changes on seismic performance of tower.The results of calculation show that the change of podium area affects the shear force at the top of the whole model most.With the podium area increasing,the inter-storey displacement and the shear force above the retracted part of the vertical shape will increase in various degrees,and the seismic performance of the whole structure will decrease.The change of tower position has little influence on the seismic performance of the whole structure.(3)At last,in the small earthquake time history analysis,to explore the internal force and deformation response of the large chassis single tower structure,the elastic-plastic time history analysis is used.Furthermore,analyzing the plastic hinges’ distribution in the elastic-plastic dynamic time history analysis of the large chassis single tower structure.The calculation results show that the separation model without skirt has better seismic performance,and the skirt will affect the distribution of plastic hinge of beam and column in elastic-plastic dynamic time history analysis.The floor at the top of podium and frame beam are regarded as the main force component between tower and podium.Tower and podium vibration tend to be more independent after power transmission components are cracked.Thus,at the stage of big chassis tower structure design,it is necessary to consider expanding the ratio of the slab of big podium.As for the the upper floor of the tower with podium,appropriate strengthening measures should be taken.