Dynamic response characteristics of steel-basalt fiber composite bar reinforced coral concrete columns under lateral impacts

In marine engineering construction, basalt fiber-reinforced polymer (BFRP) was considered a viable substitute for traditional steel reinforcement due to its superior corrosion resistance. However, the relatively weak shear resistance of BFRP leads to diminished load-bearing capacity of coral concrete structures under extreme conditions. To enhance the resilience of these structures, researchers have proposed using steel-basalt fiber composite bars (SBFCB) as an alternative to BFRP. SBFCB, which consists of basalt fibers encasing a steel core, provides benefits such as corrosion resistance, high elastic modulus, and improved secondary stiffness. Understanding the failure mechanism of SBFCB coral concrete columns under impact loading is crucial for advancing marine engineering applications. In this study, a pendulum impact system was employed to conduct lateral impact tests on nine coral concrete columns, with subsequent axial compression tests performed to assess the residual bearing capacity of the columns. The influences of impact energy, reinforcement type, and longitudinal reinforcement ratio on the dynamic response of SBFCB-coral concrete columns were evaluated by analyzing failure modes, impact forces, energy absorption rates, and residual bearing capacities. The results indicated that substituting BFRP with SBFCB significantly enhanced the impact resistance of coral concrete columns. Furthermore, the failure mechanisms of SBFCB and BFRP columns under lateral impact were thoroughly elucidated. A displacement prediction model and a residual bearing capacity prediction model for coral concrete columns were developed, effectively forecasting the maximum displacement and residual bearing capacity under lateral impact.