Low-velocity impact and post-impact flexural behavior of novel concrete seawall panels reinforced with composite GFRP bars

Abstract

Glass-Fiber-Reinforced Polymer (GFRP) bars can be used to reinforce concrete seawall structures, but there is a notable gap in the existing research regarding seawall’s impact behavior with GFRP bars. This study designed a novel GFRP-reinforced concrete seawall panel reinforced with composite GFRP bars and comprehensively analyzed their low-velocity impact behavior caused by vessel collisions for all impact characteristics: impact force, acceleration, mid-deflection, energy absorption, and strains. Furthermore, three-point flexural test evaluated the post-impact flexural behavior of the panels. The findings indicate that GFRP-reinforced seawall panels can withstand impact forces up to 1.5 m drop height (4415 J) without local and scabbing failure. The mid-deflection, total energy absorption (87 %), and the proportion of energy absorbed by GFRP bars increased with increasing drop height, whereas the ratio of energy absorption absorbed by concrete decreased significantly after 1.5 m. None of the GFRP bars ruptured even at the highest impact energy (5886 J), with maximum measured strain being 72 % of the GFRP-bar rupture strain. In post-impact, seawall panels retained 67 % of their residual flexural strength. The experimental results were verified with the modified single-degree-of-freedom (SDOF) equation. The findings enhance understanding on the relationship between impact energy and impact characteristics of GFRP-reinforced seawall panels.