Analysis Of The Influence Of Reinforced Story On Seismic Performance Of Frame-core Tube Structure

In order to meet the requirements of building function and structural safety,frame-core tube structure is widely used in high-rise structure design.Because the stiffness of the core tube is limited,designers usually set up the arm with larger stiffness in the shelter layer and equipment layer to solve this problem,and use the tension and pressure couple between the reinforced layer and the outer frame column to resist the overturning moment,so as to increase the stiffness of the structure and reduce the lateral displacement of the structure.However,the influence of the number and location of the extensors on the seismic performance of the structure deserves further study.This paper takes the frame-double core tube structure of a hotel in Hanzhong as the research object,and establishes eight computational models for laying out reinforcement stories,which are the models for laying out one,two and three layers of Vierendeel Truss reinforcement stories respectively.Under the action of frequent earthquakes,the model of frame-double core tube structure is linearly analyzed by SAP2000 finite element analysis software.The mode shapes,natural vibration period,floor lateral displacement,axial force of outer frame column and interlayer shear force,as well as base shear force and base overturning moment of each model are obtained,and the variation rules are obtained by comparing and analyzing the calculated data.Under rare earthquakes,the elastic-plastic time history analysis of the structure is carried out,and the sequence of plastic hinges,displacement response,base shear force and base overturning moment of each model are obtained.Under horizontal earthquake action in X direction and Y direction,the influence of reinforced story on shear lag effect of external frame columns is analyzed.The results show that:(1)the stiffness of the structure can be increased and the natural vibration period of the structure can be reduced by laying out the reinforcement layer.The natural vibration period of the structure decreases with the increase of the number of reinforcement layers.The natural vibration period of the structure is greatly affected by the arrangement of the first floor reinforcement layer at 0.7 times of the total height of the building,the second floor reinforcement layer at 0.3,0.7 times of the total height and the third floor reinforcement layer at 0.3,0.5 and 0.7 times of the total height respectively.(2)Arrangement of reinforcement stories can reduce the vertex displacement,floor displacement and inter-story displacement angle of the structure,and the stiffness and inter-story displacement angle change abruptly in the floor with reinforcement stories.(3)The base shear force and the base overturning moment are proportional to the number of reinforcement layers.The closer the reinforcement layer is to the base,the greater the base shear force is.The position of the reinforcement layer has little effect on the overturning moment.The ratio of the base shear force to the overturning moment of the frame column and the core tube is not significantly affected by the arrangement of reinforcement stories.(4)Arrangement of reinforcement layer can slightly reduce the axial force of flange corner column,greatly increase the axial force of flange middle column and reduce the shear lag effect,but it will cause the sudden change of the axial force of middle column,and the placement of reinforcement layer on the top floor will cause negative shear lag phenomenon in the upper part of the structure.