轻骨料混凝土无腹筋梁受剪性能试验研究

为研究骨料种类对无腹筋梁受剪性能的影响，以剪跨比和纵筋配筋率为变量，进行了16根集中荷载作用下的无腹筋混凝土简支梁受剪性能试验，其中8根采用普通碎石混凝土，8根梁采用页岩陶粒（轻骨料）混凝土，对轻骨料和普通混凝土梁的裂缝发展、破坏形态、斜向开裂荷载、受剪承载力、跨中挠度、裂缝面相对位移等进行了观察和测量。对比分析表明：轻骨料混凝土梁的斜向开裂荷载和受剪承载力均低于普通混凝土梁，其裂缝面较普通混凝土的更加光滑；将轻骨料混凝土梁受剪承载力试验值与采用我国JGJ 12-2006《轻骨料混凝土结构技术规程》和美国规范ACI 318-11、加拿大规范CSA 23.3-04、欧洲规范EC 2方法的计算值进行对比分析，结合此次试验结果和从国内外文献中搜集的126组已有试验数据，对我国JGJ 12-2006的受剪承载力公式的准确性和安全性进行探讨，提出了无腹筋轻骨料混凝土梁受剪承载力计算的建议公式。

Experimental study on shear behavior of lightweight aggregate concrete beams without stirrups

In order to investigate the influence of aggregate types on shear behavior of reinforced concrete (RC) beams without stirrups, 16 simply supported beams, which consist of 8 beams with normal concrete and 8 beams with lightweight concrete, were tested to shear failure under point load. Other main variables in the test were shear span-to-depth ratio and longitudinal reinforcement ratio. The development of cracks, failure pattern, diagonal cracking load, ultimate shear strength, beam deflection in the middle span, as well as relative displacements at crack surface of the specimens were observed and measured. By comparing and analyzing the test results, it is shown that the diagonal cracking load and ultimate shear strength of lightweight aggregate beams are smaller than those of normal beams, and the shear failure crack surfaces of lightweight aggregate beams are much smoother. The tested shear strength of lightweight aggregate beams was compared with the predictions of JGJ 12—2006, ACI 318-11, CSA 23.2-04 and EC 2. By combining the test results in this study and 126 beams collected from literatures, the shear strength equation of JGJ 12—2006 was evaluated. Finally, a new equation for shear strength of reinforced lightweight concrete beams without stirrups was proposed.