Seismic Analysis And Optimization Of Multi Story And High Rise Steel Structure Based On Performance Objective

As one of the most serious natural disasters,earthquakes have brought huge losses of life and property to human society.With the development of society and the advancement of science and technology,people’s awareness of earthquake prevention and disaster reduction has gradually increased,and national standards have increasingly higher requirements for seismic fortification of buildings.However,the existing seismic code only regards guaranteeing the safety of human life as the single fortification goal,and the seismic design concept has certain shortcomings.The performance-based seismic design of structures comprehensively considers the specific requirements of life safety and property loss,which is the current structural seismic design theory.The development direction has become a hotspot in the research of structural seismic design theory at home and abroad.Multi-story and high-rise steel structure buildings have sprung up rapidly.In particular,prefabricated steel structure buildings have received vigorous promotion and support from the country in recent years due to their green,environmentally friendly and efficient characteristics.Therefore,the seismic analysis and optimization of existing multi-story and high-rise steel structure cases based on performance objectives have important theoretical significance and engineering practical value for understanding the current status of their seismic performance and improving their seismic performance.The main work content and conclusions of this paper are as follows:(1)This paper briefly introduce the development status of multi-story and high-rise steel structure buildings and performance-based seismic theory,revealing the important significance of seismic performance design and analysis for multi-story and high-rise steel structures.(2)According to the codes of performance-based seismic design in various countries,and summarizing the previous research on seismic performance of multi-story and high-rise steel buildings,this paper puts forward a complete set of content of performance-based design of buildings,including: seismic action level,division of structural performance level,appropriate quantitative index of structural performance,performance target of structure,etc.(3)Taking the West Building of Kaier science and technology center of Shanxi gene diagnosis and drug research and development base,the first EPC assembled multi-story and high-rise steel structure public building in Shanxi Province,as the background,the finite element model of the structure is established according to the drawings,and pushover analysis is carried out by using YJK-A software,The results show that: the story drift angle index of the structure under the action of each horizontal earthquake meets the limit requirements of class II performance objectives,but under the rare earthquake action,the number of structural members with serious damage or failure exit is more.(4)Based on the analysis results of the original structure pushover,the original structure is subjected to seismic resistance by adjusting the component section,setting up seismic isolation supports,and setting up anti-buckling supports for the purpose of raising the seismic performance target of the original structure from Type II to Type III.Performance optimization,and Pushover analysis of the optimized structure.The results show that the inter-story shift angle index of the optimized structure under the action of various levels of earthquakes meets the limit requirements of the class III performance target,and makes the structure under the action of each earthquake level.The number of components whose damage degree exceeds the Class III performance target has been reduced by more than 50%.Considering that it can basically meet the requirements of Class III performance target,the seismic resistance level of the original structure has been improved by one level.(5)The elastoplastic time history analysis and the evaluation of the anti-collapse ability of the original structure and the optimized structure under the action of rare earthquakes show that the three optimization schemes reduce the inter-story displacement angle of the original structure by more than 14%.Meet the class III performance target limit.Adjusting the cross-section of the component,setting the seismic isolation support and setting the anti-buckling support respectively increased the collapse resistance coefficient of the original structure from 2.1 to 2.2,3.9 and 2.5.(6)By comparing the seismic performance indicators of different structures,it can be concluded that the seismic performance level of the seismic isolation structure is better than that of adjusting the member section,and the setting of seismic isolation supports has the most significant effect on the seismic performance level of the original structure.