砖墙轴心受压长期变形性能试验研究

Experimental study on the long-term deformation behavior of brick wall under axial compressive load

在内框架房屋中,砖墙和混凝土柱共同作为竖向构件承受竖向荷载。混凝土柱和砖墙在承受竖向荷载的过程中要产生短期变形和徐变变形。变形不一致会引起内力重分布,构件的安全储备会发生相应变化。关于混凝土柱在荷载长期作用下的变形研究较多,而关于砖墙在荷载长期作用下的变形研究未见系统报道。本文通过张拉螺杆对砖墙预压,开展了高宽比为1.1,轴压比为0.15、0.25、0.35的3片砖墙在预压力作用下的长期变形试验。考察了竖向压力随时间推移而减小的情况和竖向压应变随时间的发展情况。发现对螺杆张拉25 d左右竖向压应力和竖向压应变基本稳定。拟合得到了施加预压力26 d时不同轴压比σ0/f m下的砖墙竖向压应变计算公式。对比分析了不同实际轴压比下C30混凝土棱柱体与本文砖墙的长期竖向压应变预估值εcl及短期荷载作用下峰值应力对应的压应变,发现相同轴压比时二者长期变形接近,砖墙短期荷载作用下峰值应力对应的压应变远大于C30混凝土棱柱体。

Brick wall and concrete colmml are vertical structure and bear vertical loads together in inner-frame building. The short-term deformation and creep deformation will be produced on brick wall and concrete column under vertical load. Inconsistent deformation will cause redistribution of internal force, and the emergency capacity of structures has changed correspondingly. Many studies on the long-term deformation of concrete column are conducted, however, the long-term deformation （d brick wall has not been systematic reported. In this paper, the long-term deformation of 3 brick walls under precompression is analyzed by using tensioning screw rod to load,and taking the height-width ratio to be 1.1 and the axial compression ratio to be 0. 15, 0.25 and 0.35. The experimental results show that the vertical compressive slress and strain are stable when the screw rod has tensioned 25 days, in which the vertical compressive stress and strain decreased with time respectively are considered. The computational formula for vertical compressive strain is obtained under different axial compression ratios. The long-term vertical compressive strain and short-term compressive strain （corresponding to peak stress） pression ratios,This shows that der the same axial compression is considerably larger than C30 of C30 concrete prism and brick wall are comparatively analyzed for different axial corn- the long-term deformations of brick wall and C30 concrete prism are nearly the same un- ratio, but the short - term compressive strain （ corresponding to peak stress） of brick wall concrete prism.