大空心率 FRP-混凝土-钢组合空心桥墩的抗车辆撞击性能研究

FRP-concrete-steel double-skin tubular column (DSTC) is a novel member which consists of a FPR tube, a steel tube and an interlayer concrete infilled between two tubes, showing good corrosion resistance and seismic performance. Recently, DSTCs have been used as bridge piers, and their impact performance is one of the significant behaviors for their applications. However, most existing research focused on DSTCs with a small void ratio φ (i. e., φ is 0. 42-0. 47) or a small column diameter (i. e., D is 114-118 mm), in contrast to the recommended void ratio φ in the design code (i. e., φ is 0. 6-0. 8). In this paper, four DSTCs with a larger void ratio (i. e.,φ = 0. 73) were tested under vehicular impact, considering the influence of impact velocity (i. e.,3 m/ s and 5 m/ s) and boundary conditions (i. e., cantilever condition as well as fixed at the lower end and simply-supported at the upper end condition), and the failure mode, impact force, global deformation, energy dissipation and acceleration variation of specimens were analyzed. The test results reveal the following: higher impact velocities exacerbate specimen damage, leading to increased impact force and overall deformation. The failure mode and global deformation of DSTCs are significantly influenced by the boundary conditions. Subsequently, a finite element model was built up using LS-DYNA to analyze the energy consumption distribution of each component of DSTCs. The FE results indicate that the dynamic behavior of DSTCs is effectively predicted by the FE simulation. The interlayer concrete and steel tube are the main energy consuming components, while the energy consumption of FRP tube is relatively small.