Abstract: To apply composite tubes to the scaffolding structure, the problem of connection between members should be settled. Seeing the low transverse strength of GFRP tubes, we need to study the mechanical properties of member nodes when applying traditional steel fasteners to GFRP tube connection. In this paper, the author first imposed preload torque on GFRP tubes with cushion-free fasteners and cushioned fasteners and obtained therefrom the rules of bearing of GFRP tubes with two different fasteners. After that, based on the pretension test, the author performed the anti-slide test and studied the influence of cushions on the anti-slide bearing capacity of the nodes. In the end, the author established a finite element model of the nodes and optimized the thickness of the middle-layer cushions with the model built. The research demonstrated that: the increase in semicircular steel cushions could noticeably enhance the preload torque bearable for GFRP tubes, improve the distribution of force in GFRP tubes and better the anti-slide bearing capacity by about 26.3%. In the meantime, the finite element model indicated the appropriate cushion thickness to be 3.5 mm.

Key words: GFRP tubes, couplers, tightening torque, anti-slipping performance, experimental study, finite element analysis