两种设计原则下自定心屈曲约束支撑框架的抗震性能分析

摘要

Based on a nine-story moment-resisting braced steel frame and a nonmoment-resisting braced steel frame,a self-centering buckling-restrained brace (SC-BRB)frame was designed with the equivalent strength criterion and the equivalent core plate area criterion,respectively.The nonlinear time history analyses were conducted for six braced frame models under ten different seismic waves.The results demonstrated that compared to a BRB frame,a SC-BRB frame has a stronger capacity of restraining its residual deformation;since the structure damage caused by earthquakes of the nonmoment-resisting braced steel frame is smaller than that of the moment-resisting braced steel frame,the former exhibits a better self-centering performance;the floor acceleration and axial bracing force of the SC-BRB frame designed with the equivalent strength criterion are smaller than those of the SC-BRB frame designed with the equivalent core plate area criterion because the brace stiffness of the former is smaller;compared to the SC-BRB frame designed with the equivalent strength criterion,the SC-BRB frame designed with the equivalent core plate area criterion has a stronger capacity of restraining story drifts due to its stronger capacity of energy dissipation;furthermore,the bigger pretension force and cross-section area of braces are helpful to the improvement of the frame’s self-centering performance and the restrainment of weak stories.%基于9层支撑抗弯钢框架和支撑铰接钢框架，分别采用与屈曲约束支撑（BRB）的等强原则和等核心板面积原则设计自定心屈曲约束支撑（SC-BRB）框架，并对建立的6个支撑框架模型进行10条地震波下的非线性时程分析，结果表明：与 BRB 框架相比，SC-BRB 能有效控制结构的残余变形；因为支撑铰接钢框架由地震引起的主体结构损伤较支撑抗弯钢框架小，所以结构的自定心效果也更好；基于等强原则的 SC-BRB 框架由于支撑刚度较小，因此其结构层加速度和支撑轴力小于按等核心板面积原则设计的 SC-BRB 框架；基于等核心板面积原则的 SC-BRB 框架凭借支撑较强的耗能能力，其层间位移角的控制要优于按等强原则设计的 SC-BRB 框架，且其较大的预张力和预拉杆截面面积也更利于提高结构的自定心效果和限制薄弱层的出现。