不同刚度比下防屈曲支撑钢筋混凝土框架抗震性能试验研究

为研究不同刚度比防屈曲支撑(buckling-restrained brace，BRB)钢筋混凝土框架的抗震性能，设计并制作了3榀BRB水平刚度与主体框架抗侧刚度比值分别为3、5、7的减震框架，通过低周往复荷载试验，对比研究其耗能减震能力、破坏形态、BRB连接节点及节点板性能、BRB转动变形性能、BRB端部附加弯矩产生机制等，探讨与BRB连接的梁、柱构件设计方法。研究结果表明：3榀框架滞回曲线饱满，耗能能力稳定，随着刚度比的增加，屈服荷载及极限荷载提高，BRB连接节点破坏越严重；BRB连接节点板的存在使框架柱塑性铰位置由柱端移至节点板趾部附近区域；水平荷载作用下，各框架中BRB端部由于转动变形产生附加弯矩，转动变形与层间位移角近似呈线性变化关系；加强消能子结构的延性构造措施是实现大变形下BRB充分耗能的有效途径。

Experimental study on seismic performance of buckling restrained braced-RC frames with different stiffness ratios

To study the influence of stiffness ratio on the seismic performance of buckling restrained braced (BRB)-reinforced concrete frames, three BRB frames with stiffness ratios of three, five, and seven were designed and tested. Based on low-cycle reversed loading, the energy dissipation capacity, failure mode, mechanical performance of BRB connection joint and gusset plate, rotational deformation performance of BRB, mechanism of bending moment at end of BRB were studied. Furthermore, the design method of beam and column connected to BRB was discussed. The test results show that all the specimens develop excellent hysteretic behavior with plump hysteretic curves and stable energy dissipation. With the increase of stiffness ratio, the yield capacity and ultimate capacity of the structure are improved, while the damage of the BRB connection joint is more serious. The location of the plastic hinge is transferred to the toe of the gusset plate from the end of the column due to the existence of gusset plate. Under horizontal load, additional bending moments are generated at the end of BRB due to the rotational deformation, and the relationship between the rotational deformation and the inter-story drift ratio is approximately linear. It is an effective way to achieve the full energy dissipation of BRB under large deformation by improving the ductility of the energy dissipating substructure.