预应力砌体抗震性能的试验研究

本文通过8片不同类型的预应力混凝土小型空心砌块砌体的水平低周反复荷载试验以及2片普通混凝土小型空心砌块砌体的对比试验,研究了预应力砌体破坏形态、滞回特性、延性、刚度退化曲线等抗震性能,明确了预应力、窗洞以及构造措施对混凝土小型空心砌块墙体的开裂荷载、极限荷载和变形性能的影响。研究结果表明,预应力延缓了混凝土小型空心砌块墙体的开裂,提高了结构的开裂荷载和极限荷载;预应力改变了墙体破坏时的裂缝分布形状,裂缝密而细,几乎布满墙体全部灰缝,主裂缝不明显;预应力提高了墙体的刚度、延性和耗能能力;在窗洞底部现浇水平配筋混凝土条带能有效地抑制裂缝的产生和发展,并能提高墙体的变形和耗能能力。

Experimental study on seismic behavior of prestressed masonry

Based on the low cyclic reversed lateral loading tests on eight pieces of different types of prestressed small sized concrete hollow block masonry walls and the contrast tests of two pieces of normal small sized concrete hollow block masonry, the seismic behavior such as failure mechanism, hysteretic characteristic, ductility and curve of stiffness degradation of prestressed masonry were studied. At the mean time, the effects of prestressing force, window opening and constructional measure on cracking load,ultimate load and deformation behavior had been clarified too. The test result showed that the prestressing force delays the appearance of crack of small sized concrete hollow block masonry walls and improves the crack resistance and seismic behavior of the masonry. The prestressing force changes the distribution of the crack, the small cracks are close and fine which distribute in almost all mortar joints of the walls, while the main crack is not apparent. The prestressing force enhances the stiffness, ductility and energy dissipation capacity of the masonry. Horizontal reinforced concrete strip under the bottom of the window openings could restrain the occurrence and development of the cracks and improve the deformation and energy dissipation capacity of the walls.