Shear strengths of joints with roughened concrete surfaces and post-installed dowel bars subjected to normal and shear stresses for seismically retrofitted structures
Shear strengths of joints with roughened concrete surfaces and post-installed dowel bars subjected to normal and shear stresses for seismically retrofitted structures
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DOI：
10.1016/j.istruc.2022.09.069
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发表时间：
2022-11
期刊：
影响因子：
4.1
通讯作者：
Y. Takase;Taizo Yamada
中科院分区：
文献类型：
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作者：
Y. Takase;Taizo Yamada
当钢筋混凝土（RC）结构进行抗震加固，新的成员通过粗糙表面和后安装传力杆连接节点。对于改造后的钢筋混凝土建筑物，粗糙的表面通常使用振动锤制造。然而，在剪切和拉伸正应力的节点的抗剪强度的研究是有限的。在这项研究中，这些接头，称为混合接头，受到剪切载荷。试验参数为法向应力、传力杆直径和粗糙混凝土面积比。将正应力设定为具有-0.48N/mm2的压缩应力σ 0和0.00、0.33和0.66的拉伸应力与屈服强度的比率rN。此外，使用了dd = 13、16和19 mm的传力杆。目标值分别为0.1、0.2和0.3。作为试验结果，观察到粗糙表面的轴承失效。抗剪强度随rN的增大而减小，随rc的减小而减小。随后，粗糙表面的剪切强度的表达式提出。在这个表达式中，不平坦表面的形状被视为圆锥。为了估算混合节点的抗剪强度，将先前传力杆模型的剪切力添加到建议的表达式中。最后，将计算结果与试验结果进行了比较。结果表明，所提出的表达式可以合理地估计测试结果，相关系数为0.93。此外，对于结构设计，建议的表达式应乘以0.7，以估计测试结果的下限。
When reinforced concrete (RC) structures are seismically retrofitted, new members are connected via joints with roughened surfaces and post-installed dowel bars. For retrofitted RC buildings, roughened surfaces are often manufactured using vibration hammers. However, investigations on the shear strengths of the joints subjected to shear and tensile normal stresses are limited. In this study, these joints, called hybrid joints, were subjected to shear loading. The test parameters were the normal stress, dowel bar diameterdd, and roughened concrete area ratiorrc. The normal stress was set to have a compressive stressσ0of –0.48 N/mm2and a ratiosrNof tensile stress to yield strength of 0.00, 0.33, and 0.66. In addition, dowel bars withdd= 13, 16, and 19 mm were used. The targetrrcvalues were 0.1, 0.2, and 0.3. Bearing failure of the roughened surface was observed as a result of the test. The shear strength decreased with increasingrNand decreasingrrc. Subsequently, an expression for the shear strength of a roughened surface was proposed. In this expression, the shape of an uneven surface was regarded as a cone. To estimate the shear strengths of the hybrid joints, the shear force from the previous dowel model was added to the proposed expression. Finally, the values obtained using the calculation method were compared with the test results. It was demonstrated that the proposed expression could reasonably estimate the test results, with a correlation coefficient of 0.93. In addition, for structural designs, the proposed expression should be multiplied times 0.7 to estimate the lower limit of the test results.