A Study On Nonlinear Seismic Responses Of Frame-core Wall Structure With Outriggers

The frame core tube structure is widely used in engineering,and it is one of the main structures used in high-rise and super high-rise structures.When the lateral stiffness of the structure does not meet the requirements of the code,the strengthening layer is usually arranged in the structure to increase the lateral stiffness of the structure and reduce the lateral displacement of the structure.But the strengthening layer increases the local stiffness of the structure,and makes the structure change in the height direction stiffness,which is not conducive to earthquake resistance of the structure.The damage mechanism of reinforced concrete frame core tube structure with strengthened layer under earthquake action needs further study.This paper,designed the typical strengthened storey reinforced concrete frame core wall structure calculation model based on beam column joints under low cyclic loading and short leg shear wall is simulated and compared with the test results,the reasonable proof material model.Then select the plane frame model(outrigger truss)finite element model is established,through comparing the different component stiffness scheme,stiffness and component stiffness relationship between lateral structure research;three-dimensional finite element model is established,through the elastic and elastic-plastic time history analysis of the distribution of structural weak layer.And the sub model of the weak layer were analyzed by comparing the sub model and the whole model of the unit difference of stress and strain distribution,node displacement,to verify the accuracy of sub model in the 3D finite element calculation and rationality;and then based on the sub model method,strengthen the research of deformation characteristics and damage distribution layer near the weak zone under strong earthquake,analysis of the structure of the earthquake damage mechanism.Finally,a more accurate node sub model is established to simulate the failure process of nodes.The calculation results show that:(1)The plastic damage model of concrete and the ideal elastic-plastic model of steel can accurately simulate the nonlinear behavior of materials.(2)Analysis of the elastic time history shows that the strengthening layer has changed the stress distribution of the floor near it to a certain extent.In the strengthening layer,the interlayer displacement angle has obviously changed,and the strengthening layer and its adjacent floor are weak links.(3)The earthquake fortification intensity in Abraham under the frame column damage degree is smaller,the framework of Liang has appeared in the plastic hinge;core wall and frame beam joints with larger damage,damage degree of concrete cantilever truss connection point maximum.(4)The node sub model calculation shows that the beam column joints during earthquake end the first cracks in concrete beam with crack damage increases,column joints,crack along the horizontal direction,the core area of joint damage of concrete.(5)The calculation of elastic and elastic plastic model show the result of high precision,so it can be used in the sub model technology in finite element analysis of the structure of high-rise building.