支撑布置形式对RC框架结构的抗震性能影响

Influence of Brace Layout Forms on Seismic Performance of RC Frame Structure

框架体系中支撑的布置形式决定着结构各方面的性能,合理的布置支撑在提高结构刚度的同时可以优化结构的抗震性能.为了探究不同的支撑布置形式对框架结构的抗震性能影响,分别建立了4层和8层RC框架结构模型,利用SAP2000进行动力特性和Pushover分析,对比研究了多种支撑布置方案下结构的抗震性能.结果表明:随着支撑数量的增多,能够有效提高结构的整体刚度,降低结构的顶点水平位移,但会使得基底剪力增加显著;相同数量的支撑情况下,巨型支撑(大X型支撑)效果要优于其他支撑形式;支撑作为第一道防线,能更有效地减少梁柱中的塑性铰,从而起到对结构的保护作用;以B方案(小X型支撑)为例,在4层结构和8层结构中,支撑对结构的顶点位移减少幅度由63.6%降低到43.7%,对结构的最大层间位移角由65.1%降低到54.2%,说明支撑对结构抗震性能的影响随着楼层的增加而有所降低.

The layout of braces in the frame system determined the performance of the structure,and reasonable layout of braces can increase the structural lateral stiffness and optimize the seismic performance of the structure.In order to investigate the different layout of braces for seismic behavior of frame structure,the 4-storey and 8-storey RC frame structure models were established respectively.Dynamic characteristics and Pushover analysis were carried out by SAP2000,and layout of braces for the structural seismic behavior were studied.The results show that the increase of the number of bracings can efficiently increase the structural lateral stiffness and decrease the top horizontal displacement of the RC frame structure,but the base shear force can be increased remarkably.For the same number of bracing,the mega-brace(large X-centrically steel braces)is superior to other forms of braces.As the first anti-seismic defense line,the steel brace can effectively reduce the number of the plastic hinges for beam and column elements and play the role of protection to the RC frame structure.In 4-storey and 8-story structure,such as plan B,the top displacement of bracings can be decreased from 63.6%to 43.7%,and the inter-storey drift ratio can be decreased from 65.1%to 54.2%,it is shown that with the increase of the storey of the RC frames,the effect of steel braces on structural seismic responses is decreased.