Study On Progressive Collapse Resisting Performance And Reinforcement Method Of Annular Steel Frame

In recent years,with the rapid development of China’s economic level various forms of steel structure buildings are increasing.However,the research on the progressive collapse resistance of steel structures in China is still in its infancy,especially the research on the progressive collapse resistance of some steel frames with irregular structure layout.The methods to improve the progressive collapse resisting performance are insufficient.In this paper,the progressive collapse resisting performance of an annular steel frame structure was analyzed,and the influence of the structural layout parameters was analyzed.Finally,by comparing the tie force methods for improving the progressive collapse resisting performance and the reinforcement effect of tie force methods with different sections,the design suggestions were provided for engineering applications.The main contents include:(1)Midas/GEN was used to design the section of the annular steel frame based on an engineering example.Using finite element software ABAQUS/Explicit module,a three-dimension model of the overall structure was established.The alternative load path method was used to simulate the steel frame component failure condition.Nonlinear dynamic analysis of the remaining structure was carried out.The conditions contained single column failure,adjacent two columns failure and across the bay columns.The structural dynamic responses were discussed,and the progressive collapse resisting performance of annular steel frame structure and the internal force distribution were evaluated.(2)The influence of different layout parameters on the progressive collapse resisting performance of annular steel frame was studied,including span number,inner and outer columns distance,storey height and storey number.Based on the principle of orthogonal design parameters,Midas/GEN was used to design annular steel frame structures with different parameters,and ABAQUS/Explicit module was used to analyze the progressive collapse resisting performance of steel frames under different conditions.The effect of different layout parameters on the progressive collapse resistance of annular steel frame was disscussed.(3)The tie force method was used to reinforce the annular steel frame structure to improve its progressive collapse resisting performance.In view of the three different section forms of angle steel,steel pipe and H-section steel,4 groups of different size sections were selected for each type of section.To study the influence of the central support members with different sections on the improvement of the progressive collapse resisting performance of steel frames,so as to provide a reference for the selection of section forms in practical projects.(4)By comparing different tie force methods(including crossing braced mothod,herringbone braced method,V-shaped braced method,K-shaped braced method and the single slant braced method),the reinforcement effect on the improvement of progressive collapse resisting performance of the annular steel frame was explored.It provided a reference for the selection of the support forms of the tie force methods in practical engineering.