Strengthening of substandard reinforced concrete beam-column joints by external post-tension rods
Strengthening of substandard reinforced concrete beam-column joints by external post-tension rods
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DOI：
10.1016/j.engstruct.2015.11.004
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发表时间：
2016-01
影响因子：
5.5
通讯作者：
Ö. Yurdakul;Ö. Avşar
中科院分区：
文献类型：
--
作者：
Ö. Yurdakul;Ö. Avşar
对不符合规范要求的钢筋混凝土外梁柱节点采用外施后拉杆加固方法的有效性进行了研究。在实验室测试了五个全尺寸标本。由于接缝中缺乏抗剪钢筋和材料性能差，包括低强度混凝土和普通圆形钢筋的存在，它们具有特定的缺陷。虽然所有的试件都是用柱和平面梁建造的，但其中一个试件由横梁组成，以证明所提出的改造技术的适用性。所有试件均接受高达8%漂移比的循环准静态加载，观察不同程度的结构损伤。两个后张力杆，安装在对角线的每一边的关节，被用作局部改造技术。参考试件表现为脆性，节理处主要集中剪切裂纹，其余构件基本处于弹性范围内。所有改造后的试件的极限侧载能力均显著提高。然而，一个脆性类型的破坏机制被观察到，如节理剪切破坏或梁-节理破坏在三个改造的标本。尽管后拉杆的轴力与无横向梁的试件相同，但在有横向梁的试件中观察到相对延性的响应。在对所有试件进行测试后，发现通过提出的改造方法，梁柱组合的侧力能力可以提高到规范要求。
The efficiency of the proposed strengthening method using externally applied post-tension rods in reinforced concrete external beam-column joints, which do not comply with any code requirements, is investigated. Five full-scale specimens were tested in the laboratory. They have specific deficiencies resulting from the lack of shear reinforcement in the joint and poor material properties including low strength concrete and the presence of plain round reinforcement bars. While all specimens were built with column and in plane beam, one of the tested specimens consists of a transverse beam to demonstrate the applicability of the presented retrofit technique. All specimens were subjected to a cyclic quasi-static loading up to 8% drift ratio to observe different levels of structural damage. Two post-tension rods, which were mounted diagonally at each side of the joint, are utilized as a local retrofit technique. The reference specimen displayed a brittle behavior with the concentration of shear cracks mostly in the joint while the rest of the RC components were almost in their elastic range. The ultimate lateral load capacity was increased considerably for all retrofitted specimens. However, a brittle type of failure mechanism was observed such as a joint shear failure or beam-joint failure in the three retrofitted specimens. A relatively ductile response was observed in the specimen with transverse beam, although the axial force in the post-tension rods was the same with the specimens without transverse beam. After testing all specimens, it is found that the lateral force capacities of the beam-column assemblies can be improved up to code requirements by the proposed retrofitting method.