Numerical Simulations and Simplified Design Approaches for Large-Rupture-Strain FRP-Strengthened Reinforced Concrete Beams under Impact

Abstract

Due to the ductile properties of large-rupture-strain fiber-reinforced polymer (LRS-FRP) laminates and their confined concrete, the failure patterns and ultimate deformation capacities of LRS-FRP-strengthened reinforced concrete (RC) beams were considerably different from those of their carbon FRP (CFRP)-strengthened counterparts under static and impact conditions. This study investigates the dynamic behaviors of LRS-FRP-strengthened beams under impact using high-accuracy numerical models and simplified analytical approaches. First, high-fidelity finite-element (FE) models were created to evaluate the static and impact responses of LRS-FRP-strengthened RC beams with varied failure patterns recorded in prior experiments. Subsequently, based on the validated FE model, the effects of critical variables, such as impact energy, longitudinal FRP strengthening ratio, wrapping length, and types of FRP, on the dynamic response were investigated. In addition, a simplified design model for a rapid evaluation of the performance and safety conditions of FRP-strengthened RC beams under impact was presented, which considered the energy conservation during the impact process, material strain rates, and influences of failure patterns. Extensive data from the static and impact tests with various failure patterns were used to verify the accuracy of the model. Finally, the simplified model yielded an impact mass/impact velocity (m–v) diagram, demonstrating that LRS-FRP-strengthened RC beams outperform their CFRP counterparts in terms of anti-impact performance by obtaining a larger ultimate deformation capacity and greater safety margin.