角钢拼接十字形无焊核心的高性能屈曲约束支撑试验研究

摘要

To avoid the reduction of low cycle fatigue performance due to welding in the steel core of cruciform cross-section of conventional buckling-restrained braces (BRBs), a new type of welding-free cruciform-shaped BRB with angle steel splicing core was developed.Uniaxial quasi-static cyclic tests for three BRB specimens were carried out to investigate the hysteretic behavior.The steel core of BRB consists of four combined angle steels with equal sides to form a welding-free cruciform cross-section using structure glue, to avoid uncontrollable defects from welding or directly casting.The test results indicate that this type of BRB specimens has stable hysteretic performance.Before the fracture of the first angle steel, the cumulative plastic deformation capacity of the specimens is much higher than that of the casting cruciform cross-section BRB and better than that of the rectangle cross-section BRB with end welding stiffening rib.After the fracture of the first angle steel, the rest sections of angle steel still have energy dissipation capacity.The tension and compression coefficients of the three specimens are all below 1.1, so the limit value of AISC 1.3 is satisfied.%为避免十字形截面屈曲约束支撑的内芯在焊接后对低周疲劳性能的不利影响,提出核心部件采用角钢拼接的无焊十字形截面.进行了3根屈曲约束支撑试件的拟静力滞回性能试验,其中无焊核心部件采用黏钢胶拼接4根等边热轧角钢的方法,避免焊接或直接铸造试件中不可控缺陷的产生.试验结果表明,该类支撑的滞回性能稳定,第1根角钢断裂前,试件的累积塑性变形能力远高于铸造十字形截面,比端部焊接加劲肋的一字形核心屈曲约束支撑也有所提高.在第1根角钢断裂后,剩余截面仍具有相当的耗能能力.3根试件的拉压不平衡系数均在1.1以下,满足AISC规定的1.3限值要求.