钢筋混凝土加强墙的底层大开洞砌体结构抗震性能试验研究∗

Experimental Study on Seismic Performance of Masonry Structure with Large Openings at the Bottom Floor of Reinforced Concrete Walls

摘要:

针对砌体结构为满足底层功能需求而扩大洞口导致其抗震性能削弱、安全性降低的问题，按1∶4比例设计制作了一栋四层砖混结构缩尺模型，并基于刚度等效的原则在底层大开洞一侧以钢筋混凝土加强墙置换部分传统砌体墙，对其进行低周往复加载试验，得到结构各层的破坏形态、位移变化、滞回曲线、骨架曲线以及刚度退化等抗震性能指标。结果表明：砌体结构与钢筋混凝土加强墙紧密联结，结构整体具有延性特征；结构未发生承载力突变， 保持较好的抗震耗能性能；结构二层位移显著，设计时应着重关注其刚度，避免形成薄弱层；设钢筋混凝土加强墙可避免地震中底层大开洞砌体结构的扭转。

Abstract:

To address the issues of weakened seismic performance and reduced safety caused by the expansion of openings at the bottom floor of masonry structure to meet the functional requirements, a 1: 4 scale model of a four-story brick-concrete masonry structure was designed and constructed. Based on the principle of stiffness equivalence, part of the traditional masonry walls on the side of the bottom floor with large openings were replaced by reinforced concrete walls. The low-cycle loading test was conducted to evaluate the seismic performance, including failure mode, displacement variation, hysteresis curve, skeleton curve, and stiffness degradation at each floor of the structure. The results showed that the masonry structure was closely connected with the reinforced concrete walls, endowing the whole structure with the characteristic of ductility. The structure had no sudden change in load bearing capacity and maintained good seismic energy dissipation performance. The displacement of the second floor of the structure was significant, and its stiffness should thus be prioritized during the design process to avoid the formation of a weak floor. Using reinforced concrete walls can effectively prevent torsion of the masonry structure with large openings at the bottom floor during earthquakes.