预应力加固两层足尺砖砌体房屋模型抗震性能试验研究

针对砖砌体结构抗震性能差的问题，提出了采用竖向无粘结预应力筋对砖砌体结构进行加固的新型抗震加固技术。为研究加固效果，进行了一栋两层足尺砖砌体房屋模型模拟地震作用的拟动力试验与拟静力试验研究。试验测试了模型结构的动力特性和在不同方向、不同量级拟动力地震作用下的位移反应，研究了在拟静力试验工况下的破坏形态和受力性能。结果表明，加固前设防烈度不足8度的砖砌体结构，加固后在相当于9度大震（620伽）的拟动力作用下基本处于弹性状态，且结构两个方向的抗剪承载力与房屋总重量之比分别达到1.24和1.41，抗震承载力显著提高。加固后结构的荷载-位移滞回环饱满，骨架曲线下降段平缓，表现出良好的耗能和变形能力。水平荷载卸除后，预应力筋对于房屋有明显的复位作用，有助于实现大震不倒。

Pseudo-dynamic test and quasi-static test of full-scale model of a two-story brick building retrofitted with prestressed tendons

 A new seismic retrofitting method with vertical unbonded prestressed tendons adopted is proposed to improve the seismic behavior of brick structure．To investigate the retrofitting effects, a full-scale two-story brick building was built and tested under the pseudo-dynamic load and quasi-static load, respectively. The dynamic behaviors and the displacement responses of the building in different directions and with different magnitudes of pseudo-dynamic load were measured, and the failure modes and the mechanical behaviors under the quasi-static load were studied. It is observed that the original brick building, which has a seismic fortification intensity less than 8 degree before the seismic retrofitting, may remain in the elastic state when it is subjected to the pseudo-dynamic impact equivalent to a strong earthquake of 9 degree seismic fortification intensity (620gal) after the seismic retrofitting; the obtained shear capacity in two directions is equivalent to 1.24 and 1.41 times the total weight of the building, respectively, indicating that the seismic capacity of the brick building has been significantly improved. Meanwhile, the load-displacement hysteretic loops are full and the descending portion of the skeleton curve is flat, exhibiting good energy dissipation capacity and deformability. In addition, when the lateral loads are removed, the position restoration behavior of the building can be improved significantly by the prestressed tendons, which is helpful for avoiding the collapse of the building during a strong earthquake.