砌块整浇墙骨架曲线影响因素分析

Analysis of influencing factors on the skeleton curve for fully grouted reinforced concrete masonry shear walls

摘要:

为确定290 mm厚砌块整浇墙在不同破坏模式下的抗剪性能和变形能力,完成了10片足尺290 mm厚全灌芯配筋砌块砌体剪力墙低周往复荷载试验．试验中采用1 000 kN千斤顶施加竖向力,630 kN液压伺服水平作动器施加水平力,研究墙体在压弯剪共同作用下的抗震性能．利用试验记录提出的骨架曲线,研究了竖向压应力、水平配筋、竖向配筋等参数对该种墙体骨架曲线的影响．试验结果表明:在一定范围内,随着竖向压应力提高,墙体受剪承载力和变形能力都有提高;水平配筋对墙体抗剪性能的影响与墙体破坏模式有关,当墙体发生剪切破坏时具有较高水平配筋率的墙体抗剪能力较高但延性较差,而墙体发生弯曲破坏时延性却较好;竖向配筋对墙体抗剪承载力影响显著,对墙体延性的影响与所受竖向压应力大小有关．

Abstract:

To determine the shear-resistance performance and deformability of 290 mm-width fully grouted reinforced concrete masonry (FGRM) shear walls under different failure modes, ten full-scale walls were tested firstly under low cyclic reversed lateral loads simulated by a 1 000 kN jack providing constant axial load and a 630 kN servo controlled hydraulic actuator producing low cyclic reversed lateral loads. The seismic performance of walls bearing compress, shear and flexure is studied. Meanwhile, the skeleton curves of FGRM shear walls based on the data recorded in the tests are investigated considering different factors including the axial compressive stress, the horizontal reinforcement, the vertical reinforcement, et al. It is demonstrated that, firstly, both the shear and deformation capacity can be improved as the axial compressive stress increases within a certain range. Secondly, the impact of horizontal reinforcement on the shear-resistant performance of walls is related to failure modes of the wall. Compared with the flexural failure mode, a much higher shear capacity but a worse ductility is derived in a shear failure mode when the walls are confirmed with higher horizontal reinforcement. Finally, the wall shear capacity is influenced significantly by the vertical reinforcement whose effects on ductility are associated with the applied axial stress.