Bywalski Czesław, Drzazga Michał, Kaźmierowski Maciej, Kamiński Mieczysław
Faculty of Civil Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
Materials (Basel). 2020 Mar 5;13(5):1159. doi: 10.3390/ma13051159.
The article presents experimental tests of a new type of composite bar that has been used as shear reinforcement for concrete beams. In the case of shearing concrete beams reinforced with steel stirrups, according to the theory of plasticity, the plastic deformation of stirrups and stress redistribution in stirrups cut by a diagonal crack are permitted. Tensile composite reinforcement is characterized by linear-elastic behavior throughout the entire strength range. The most popular type of shear reinforcement is closed frame stirrups, and this type of Fiber Reinforced Polymer (FRP) shear reinforcement was the subject of research by other authors. In the case of FRP stirrups, rupture occurs rapidly without the shear reinforcement being able to redistribute stress. An attempt was made to introduce a quasi-plastic character into the mechanisms transferring shear by appropriately shaping the shear reinforcement. Experimental material tests covered the determination of the strength and deformability of straight Glass Fiber Reinforced Polymer (GFRP) bars and GFRP headed bars. Experimental studies of shear reinforced beams with GFRP stirrups and GFRP headed bars were carried out. This allowed a direct comparison of the shear behavior of beams reinforced with standard GFRP stirrups and a new type of shear reinforcement: GFRP headed bars. Experimental studies demonstrated that GFRP headed bars could be used as shear reinforcement in concrete beams. Unlike GFRP stirrups, these bars allow stress redistribution in bars cut by a diagonal crack.
本文介绍了一种新型复合筋的试验测试，该复合筋已被用作混凝土梁的抗剪钢筋。在使用钢箍筋对混凝土梁进行抗剪加固的情况下，根据塑性理论，允许箍筋发生塑性变形以及由斜裂缝切断的箍筋中的应力重新分布。抗拉复合筋在整个强度范围内均表现出线弹性行为。最常用的抗剪钢筋类型是封闭框架箍筋，其他作者曾对这种纤维增强聚合物（FRP）抗剪钢筋进行过研究。对于FRP箍筋，其会迅速发生破坏，抗剪钢筋无法进行应力重新分布。通过对抗剪钢筋进行适当塑形，试图在传递剪力的机制中引入准塑性特性。试验材料测试包括测定直玻璃纤维增强聚合物（GFRP）筋和带封头GFRP筋的强度和变形能力。开展了采用GFRP箍筋和带封头GFRP筋的抗剪加固梁的试验研究。这使得能够直接比较采用标准GFRP箍筋加固的梁与一种新型抗剪钢筋：带封头GFRP筋的梁的抗剪性能。试验研究表明，带封头GFRP筋可用作混凝土梁的抗剪钢筋。与GFRP箍筋不同，这些钢筋允许由斜裂缝切断的钢筋中的应力重新分布。
