Research On Seismic Performance Of Oversized High-rise Buildings With Flat And Long Plane Shapes

Due to the reasons of architectural modeling and the fact that some office buildings have residential properties,more and more super high-rise buildings with flat shapes are appearing in actual projects.The length-width atio of such buildings is generally large.In order to pursue good building functions and effective use area,a frame-core tube structure system is adopted.It will lead to the structural lateral stiffness,the torsional stiffness is insufficient,and the dynamic characteristics of the two main axes are obviously different,which is extremely unfavorable to the earthquake resistance of the structure.In recent years,most of the research has been to strengthen the layer as a way to improve structural rigidity.The reinforcement layer causes the structure to have a sudden change in stiffness,forming a weak layer.This paper mainly studies the influence of adding shear wall to flat frame core tube structure on lateral stiffness and torsional stiffness,And the seismic performance of the special frame core tube structure with shear wall in elastic and elastoplastic stage.To explore a more suitable structural scheme for flat and long super tall buildings.Firstly,the simplified model of frame core tube with flat length is established.According to the different horizontal distance between the added wall and the rigid center of the structure,the influence of the added wall on the dynamic characteristics and displacement response of the structure is studied.Summarize the effective measures to improve the lateral and torsional stiffness of the frame core tube structure.Secondly,according to the above research results,relying on the actual project,the anti lateral force system of a elliptical super high-rise building is improved and optimized.Develop a special frame core tube optimization scheme with shear wall at the end.Based on the set seismic performance target.PKPM finite element software is used to carry out elastic static analysis and elastic time history supplementary analys is of the optimization scheme under the action of frequent earthquakes.Further verified the reasonable and effective strengthening measures.Then,in order to study the difference of seismic performance and failure mechanism between frame core tube structure with shear wall and common frame core tube structure under the condition of similar lateral stiffness in elastic stage,Establish a comparison scheme by expanding the core tube.YJK finite element software is used to analyze the static elastoplastic comparison of the two schemes under rare earthquake.In order to obtain a specific and exact elastoplastic eismic response of the frame-core tube structure with shear wall under rare earthquakes,the ABAQUS finite element software was carried out to evaluate the seismic performance of the structure.The damage analysis and plasticity development of each main component were analyzed in detail.The main conclusions are as follows: The shear wall arranged on both sides of the short axis of the core tube can form a joint wall with the core tube to effectively improve the lateral stiffness,but the torsional effect is obvious.The shear wall is arranged at the end of the building on both sides of the long axis of the core tube,which has little contribution to the lateral stiffness,but can significantly enhance the torsional stiffness of the structure.The frame core tube structure with shear wall at the end can effectively improve the y-direction lateral stiffness and the overall torsional stiffness of the flat building,and improve the dynamic characteristics of the main shaft of the structure,No weak layer and sudden change of bearing capacity.Under a large earthquake,the structure can meet the performance target of "no collapse under a large earthquake",the structure enters into a distinct elastoplastic hierarchy,and plays a multi-channel anti-seismic defense mechanism,with good anti-seismic performance,Its energy consumption and failure mechanism are consistent with that of the common frame core tube structure,but its displacement control ability is better than that of the common frame core tube scheme.To some extent,it can improve the safety reserve of the structure under the rare earthquake and reduce the repair cost of the structure after the earthquake.