Nonlinear Finite Element Analysis On Lateral Performance Of RC Tall Frame Structure With Different Ratio Of Cross-floor Columns

In order to meet the needs of modern architecture in the use of functional,architectural modeling and spatial effects,high-rise building structures with through columns are more widely used.Because there are many kinds of high-rise building structural systems and the project situation is complex and changeable,the influence of the column passing through the floor on different projects and different structural systems is not the same.So far,there are many researches on complex structures such as frame-shear wall and frame-tube structures with through-story columns at home and abroad,but there are few literatures on the lateral resistance of frame structures with through-story columns.The existing studies mainly focus on the influence of a few or several through-story columns on the lateral resistance of the whole frame structure,and focus on the stress state and safety of the through-story column itself.The potential "second line of seismic resistance" of RC frame structures with through-story columns has not been systematically studied.In this paper,the redistribution of internal force and the law of failure process of RC high-rise frame structure with cross-storey columns and ordinary frame columns are discussed in order to provide valuable academic reference for engineering design and theoretical research.According to the current national code,ten 8-story RC space frame structure models with through-floor columns are designed and established by SATWE software according to five different proportions of through-floor columns and two types of through-floor columns;The static simulation analysis under longitudinal and transverse horizontal earthquake was carried out by using the efficient and refined nonlinear finite element analysis program VFEAP,which can consider the spatial synergistic effect of beam,slab and column.The influence of the change of the proportion of cross-storey columns and the number of cross-storey columns on the overall lateral resistance performance of RC frame structure and the internal force redistribution and damage process of frame columns(including cross-storey columns and ordinary frame columns)was systematically studied;Through the dynamic elastic-plastic time-history analysis of 10 frame structure models by SAUSAGE software,the damage situation of cross-storey columns and ordinary frame columns is observed,which provides a reference for judging the different damage degrees of cross-storey columns and ordinary frame columns;Compare and analyze the level limit load value of VFEAP program static simulation analysis with the design earthquake action value obtained by SAUSAGE software dynamic elastic-plastic analysis and SATWE software engineering design analysis of the corresponding model,mutually check the analysis results,and scientifically judge.The influence of the ratio of cross storey columns and the number of cross storey on the lateral bearing capacity margin of RC frame structures with cross storey columns designed according to the current code.The main conclusions of this paper are as follows:With the increase of the ratio of the columns passing through the floor,there is a turning point when the ratio of the columns passing through the floor is 50%-66.7%,and the maximum inter-story drift angle changes from increasing to decreasing with the increase of the ratio,and the damage situation of the columns and ordinary columns also changes accordingly,that is,under the ultimate load,the damage situation changes from more serious to more serious;The frame structure with three layers of high through-floor columns has the above turning point when the proportion of through-floor columns is 33.3%-50%;The larger the ratio of cross-storey columns,the lower the ultimate lateral bearing capacity,the steeper the stiffness degradation curve,and the higher the degree of shear redistribution.With the increase of the ratio of cross-storey columns,the degree of shear redistribution increases from 0.107 to 0.362 for the frame structure with two-storey columns,and from 0.118 to 0.366 for the frame structure with three-storey columns.The degree of shear redistribution along the longitudinal direction is slightly lower than that along the transverse direction;Under moderate and rare earthquakes,the margin of lateral bearing capacity of the frame structure with two-story high through-story columns designed according to the current code changes from increasing with the increase of the proportion of through-story columns to decreasing gradually when the proportion of through-story columns is 50%-66.7%,while the margin of lateral bearing capacity of the frame structure with three-story high through-story columns changes when the proportion is33.3%-50%;At the same ratio of columns passing through floors,when the number of columns passing through floors is changed from two to three,the overall lateral resistance of the structure is weakened,and the degree of shear redistribution is slightly reduced,while the shear distribution of ordinary columns is slightly increased;The position of "turning point" and the change of "redundancy" related to the results of VFEAP program static nonlinear simulation analysis,SAUSAGE software dynamic elastic-plastic time history analysis and SATWE software engineering design analysis are consistent with each other.