Abstract: In this paper, a prepreg fiber-reinforced composite material combined with nitrile rubber is used to design a combined wrapping system for the protection of the main cable of a suspension bridge, and the circumferential expansion performance of the system is experimentally studied. Comparative analysis of the differences in the failure modes of each group of components, most of the components fracture vertically at the overlap transition. Based on the hoop bearing capacity-radial displacement curve, the effects of changes in the number of prepreg layers and rubber band layers on the hoop bearing capacity and radial displacement of the component can be obtained. The increase in the number of prepreg layers has the largest contribution to the bearing capacity of the hoop component, with a growth rate of 65.31%-109.01%; the increase in the number of rubber band layers has the most significant effect on the radial displacement of the component, with a growth rate of 7.06%-23.5%. According to the analysis of the component′s circumferential strain-radial displacement curve, it can be seen that the compaction of the component by the loading device at the initial stage of the test results in small strains in the various parts, and the strain value of the component increases approximately linearly during loading, with the overlap strain being the smallest. The addition of rubber bands can increase the deformation of the main cable, and the protection system has more deformation redundancy, which delays the arrival of the ultimate strain of the outer prepreg wrapping tape.

Key words: FRP, nitrile rubber, suspension bridge, main cable protection system, ring expansion test, failure mode