全钢自复位屈曲约束支撑理论与数值分析

Theoretical and numerical investigations on an all-steel self-centering buckling-restrained brace

为控制地震作用下框架结构的最大层间位移和残余变形,给出一种基于全钢屈曲约束支撑的自复位耗能支撑的设计思路。这种自复位屈曲约束支撑采用预应力钢绞线作为自复位系统,所以被称为全钢自复位屈曲约束支撑。为克服预应力钢绞线极限弹性变形的限定,给出一种串联两束预应力筋的设计构造。理论分析表明:这种串联两束预应力筋自复位系统使得自复位屈曲约束支撑的轴向变形是单束预应力钢绞线作为自复位系统时的两倍;同时指出,预应力筋的初始预张力应大于给定值,才能够保证自复位屈曲约束支撑的性能;根据上述分析同时给出了一种可能的全钢自复位屈曲约束支撑的设计方案;数值模拟表明减小自复位屈曲约束支撑核心板屈服段的长度可以提高支撑的耗能能力。

A new self-centering energy-dissipative brace is developed based on the all-steel buckling-restrained brace to control maximum and residual drift of frame stuctures subjected to several earthquakes. This energy-dissipative brace employs the steel prestressing tendons as the self-centering system. Therefore,it is called the self-centering all-steel buckling-restrained brace in this paper. To overcome the limitation of elastic deformation of the prestressing tendons,an enhanced-elongation dual-tendon system has been designed. Theoretical study shows that this dual-tendon system allows for self-centering response over two times the range achieved with the original self-centering system with the prestressing tendon. Furthermore,when the initial prestressing force is larger than the given value,the performance of the selfcentering buckling-restrained brace can be achieved. Based on the discussion,one possible realization of this system,which combines the merits of both self-centering devices and buckling-restrained braces,is presented. Numerical results shows that if the length of the yielding segment of the core brace is decreased,the performance of the self-centering BRB is improved.