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根据集中荷载作用下8根剪跨比0.26~1.04、跨高比为2和3的LC40级高强轻骨料混凝土简支深受弯构件受剪性能试验结果,重点分析了该类混凝土深受弯构件的破坏过程与破坏形态。在试验研究的基础上,建立了基于软化拉-压杆模型计算理论的高强轻骨料混凝土深受弯构件受剪承载力计算模型,并应用该模型完成了22组该类构件受剪承载力试验计算与我国GB50010-2010、ACI318-08、CSA和EC2等现有规范计算结果及软化拉-压杆模型计算结果的对比分析。分析表明:高强轻骨料混凝土深受弯构件破坏形态分为剪切破坏和弯剪破坏两种,剪跨比λ≤1,其受剪承载力基本由混凝土斜压杆控制,软化拉-压杆模型计算结果接近试验值,与现行规范计算结果相当,但软化拉-压杆模型有明确的力学模型,能够合理反映深受弯构件受力机理。
According to the test results of shear strength of 8 RC beams with LC40 grade of high strength lightweight aggregate concrete with a span-to-shear ratio of 0.26 to 1.04 and span ratios of 2 and 3 under concentrated load, this kind of concrete is deeply analyzed Failure process and failure mode of components. Based on the experimental study, the calculation model of shear strength of high strength lightweight aggregate concrete members with high strength is established based on the theory of softening pull-strut model, and the shear strength of 22 groups of such members is fulfilled by this model. The experimental calculation is compared with the calculation results of the existing codes such as GB50010-2010, ACI318-08, CSA and EC2 and the calculation results of the softened pull-strut model. The analysis shows that the failure mode of high strength lightweight aggregate concrete under deep bending is divided into shear failure and shear failure. The ratio of shear span λ is less than or equal to 1, and its shear capacity is basically controlled by concrete bar, The calculation results of the rod model are close to the experimental values, which are equivalent to those calculated by the current code. However, the softening pull-rod model has a clear mechanical model that can reasonably reflect the stress mechanism of deep flexural members.