Experimental Research on Mechanical Properties of Semi-Grouting Sleeve Connection After Being Subjected to High Temperature
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摘要: 研究了高温对灌浆料抗压强度的影响,并推导得到高温后灌浆料抗压强度的计算式。为了研究高温后半灌浆套筒连接的力学性能,以温度、锚固长度、保护层厚度为变量,设计了高温后半灌浆套筒连接的拉拔试验。试验结果表明:试件的破坏模式随着温度的升高,从钢筋断裂破坏逐渐变为钢筋拔出破坏;增加锚固长度可以有效提高半灌浆套筒连接的力学性能,在600℃时,锚固长度为120 mm的试件极限荷载和极限位移的损失分别为6%和46%,远远小于锚固长度为100 mm的试件;保护层的存在有利于提高半灌浆套筒连接的承载力和延性。根据试验结果推导得到高温后半灌浆套筒连接的承载力计算式,计算值和试验值吻合较好。Abstract: The compressive strength of grout after high temperature was studied, and the formula for calculating the compressive strength of grout after being subjected to high temperature was derived. In order to study the mechanical properties of semi-grouting sleeve connection after of high temperature, the pull-out test of semi-grouting sleeve connection after being subjected to high temperature was designed with temperature, anchorage length and protective layer thickness as variables. The test results showed that the failure mode of specimens changed with the increase of temperature, and the failure mode changed gradually from steel bar fracture failure to steel bar pull-out failure. Increasing anchorage length could effectively improve the mechanical properties of semi-grouting sleeve connections. At 600℃, the ultimate load and ultimate displacement losses of specimens with anchor length of 120 mm were 6% and 46% respectively, which were far smaller than those of specimens with anchor length of 100 mm. The existence of protective layer was beneficial to improve the bearing capacity and ductility of semi-grouting sleeve connections. Based on the test results, the bearing capacity formula of semi-grouting sleeve connection after being subjected to high temperature was deduced, and the predicted values were in good agreement with the test values.
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