高强珊瑚骨料混凝土梁受剪承载力试验研究与设计方法评估OA

To investigate the shear performance of reinforced high-strength coral aggregate concrete(HSCAC)beams,both experimental and theoretical studies were carried out.A total of eight shear beams were tested,using a three-point loading scheme,to investigate the failure patterns,load-carrying capacity and strain development in reinforcements.The parameters considered for test specimens were shear span-to-depth ratio(1-2.5),grade of concrete strength(C30～C70),area ratio of longitudinal rebars(2.06％-2.55％)and stirrups(0.25％-0.38％).Further,the predictive performances of ACI 318-19 and GB 50010-2010 formulas as well as the simple strut-and-tie model(STM)to calculate the shear capacity were evaluated and compared in detail.The test results identify four failure modes which are found for HSCAC shear beams,including the shear-compression,diagonal compression,shear-flexural and shear-bond failure;the concrete spalling of HSCAC beams with a shear-compression or diagonal compression failure are more severe than ordinary concrete specimen;the shear strength is significantly affected by shear span-to-depth ratio and concrete strength.As for the design methods to determine shear capacity of HSCAC beams,the ACI 318-19 and GB 50010-2010 equations would provide conservative predictions,with an average predicted-to-test shear capacity ratio of 0.31 and 0.56,respectively.Meanwhile,the STM,which only considers the failure of inclined and horizontal struts,could obtain a relatively higher predictive accuracy,with a mean value of predicted-to-test shear capacity ratio of 0.92.Based on the analysis,GB 50010-2010 formula or the STM,simultaneously considering the destruction of tie,inclined and horizontal struts,are suggested for conservative shear design,and the STM,only considering the failure of inclined and horizontal struts,for precise prediction.