Enhancement of basalt FRP by hybridization for long-span cable-stayed bridge

This paper presents an enhancement method for basalt fiber-reinforced polymer (BFRP) and the corresponding design optimization for application in long-span cable-stayed bridge. Based on previous studies of long-span cable-stayed bridge with FRP cables, the limitations of BFRP cables were first clarified and potential enhancement methods were proposed from both material and structural design perspectives. The basic mechanical properties and fatigue behavior of BFRP and the related hybrid FRP were experimentally studied and the hybrid effect on enhancing both types of properties was assessed. To address the improvement of utilization efficiency of FRP cables, design optimization of various FRP cables were proposed in terms of material enhancement and structural design requirement of long-span cable-stayed bridges. The results show that hybridization of basalt and carbon fibers not only increase the overall potential strength and the modulus but also enhance the fatigue behavior in comparison to basalt FRP. Meanwhile, hybrid basalt fiber and steel-wire FRP exhibits higher initial modulus and maintain high failure strain. Furthermore, design recommendation of FRP cables proposed in terms of lower limit, upper limit of safety factors and practical consideration result in FRP cables achieving higher integrated performance compared to those by conventional design.