Monotonic loading performance of GFRP beam-column joints connected with slotted–hole bolts

Nowadays there are many types of glass fiber reinforced polymer(GFRP) composite beam and column joints, such as standard connection, bolted through connection, angle steel connection, tube connection and so on, most of which connected by high-strength bolts with round holes. In this paper, monotonic loading tests on GFRPcomposite beam and column joints connected by slotted-hole bolts were conducted. To compare the performance of different joints, two groups of specimens were used in this study; one of group was the beam-column joints connected by the angle steel, and other group was connected by the tube connection. Specimens with different bolt holes, side plate reinforcement condition, and different bolt pre-tightening forces were studied. Failure modes, bending moment curves, plastic rotation, and yield stiffness of the two groups of joints were compared. Results showed thatthe ultimate bending moment bearing capacity of specimens with side plates could be increased by 30%. Under the same conditions, the bearing capacity of the tube joints was about 10% larger than that of the angle steel joints. Although the bearing capacity of joints was not increased by using slotted holes, plastic rotation capacity and yield stiffness of joints with slotted-hole bolts were 1.1 times than that of the ordinary round-hole bolts joints.

当前存在多种类型的玻璃纤维增强聚合物（Glass Fiber Reinforced Polymer，GFRP）复合材料梁柱节点，诸如标准连接、贯通螺栓连接、角钢连接、套管连接等形式，其中多数采用圆孔高强度螺栓进行连接。本文针对采用长圆孔螺栓连接的GFRP复合材料梁柱节点开展了单调加载试验。为对比不同节点的力学性能，本研究设置了两组试件：一组为角钢连接梁柱节点，另一组为套管连接梁柱节点。本次研究涵盖了不同螺栓孔形式、侧板加固工况以及不同螺栓预紧力的试件。研究对比了两组节点的破坏形态、弯矩曲线、塑性转角以及屈服刚度。试验结果表明，增设侧板的试件其极限弯矩承载力可提升30%。在相同工况下，套管连接节点的承载力较角钢连接节点高出约10%。尽管采用长圆孔螺栓并未提升节点的承载力，但采用长圆孔螺栓的节点其塑性转角能力与屈服刚度均为普通圆孔螺栓连接节点的1.1倍。