受压弯剪型开孔芯材屈曲约束支撑试验

Experiments on Perforated Buckling Restrained Braces with Bending-shear Deformation under Compression

提出一种芯材开孔的新型全钢屈曲约束支撑,简称为PBRB.该支撑由开孔平板芯材,填充板及盖板通过螺栓连接而成.通过3根芯材具有不同开孔形式的PBRB试件的拟静力试验和相关数值分析,重点考察了芯材开孔形式对PBRB抗震性能的影响.研究结果表明:PBRB具有滞回性能稳定、延性高及累积耗能能力优良等特点;开孔芯材受压变形为压缩、剪切与弯曲组合的机制;开孔芯材"短柱"的长细比是影响PBRB性能的关键参数,芯材"短柱"长细比过大会造成PBRB滞回性能相对较差,基于试验结果给出了偏保守的设计长细比限制;同时提出了PBRB初始刚度的计算方法,评估精度良好.

A novel type of steel buckling-restrained braces(BRBs) is proposed, in which the core plate is perforated, termed as PBRB. PBRB is composed of a perforated core plate, 2 filling plates and restraining plates, which are assembled by bolts. Quasi-static cyclic tests and the corresponding numerical analyses were carried out on 3 specimens with different configurations of holes, the effect of which on the seismic performance was investigated emphatically. It was showed that PBRBs had stable hysteretic properties, high ductility and energy dissipation capacity.The compressive deformation of perforated core plates was found to be composed of compression, shear and flexural deformation. The slenderness ratio of "stub columns" is a critical parameter that affects seismic performance of PBRBs. An oversized slenderness ratio can lead to relatively poor seismic performance. A conservative design limit for the slenderness ratio was proposed based on the experimental results. A method with good accuracy has been proposed to evaluate initial stiffness of PBRBs.