GFRP-Retrofitted Reinforced Concrete Columns Subjected to Simulated Blast Loading

Abstract

This paper presents experimental results of one as-built and three glass-fiber-reinforced polymer (GFRP)-retrofitted reinforced concrete columns subjected to simulated blast loading. Retrofitting involved various configurations of longitudinal and transverse GFRP layers to enhance flexural and shear capacity. The objective was to study the performance and level of protection of the retrofitted columns to mitigate blast effects. The results demonstrated that retrofitting can significantly increase the strength and stiffness of reinforced concrete flexural members and greatly improve blast response. Furthermore, the addition of transverse GFRP wraps can lead to enhancements in the debonding strain and behavior of longitudinal GFRP, as well as an increase in postpeak ductility of concrete. A complementary analytical study based on the single-degree-of-freedom (SDOF) dynamic analysis method was conducted to predict the displacement response of the columns. The load–deformation relationships of the columns were computed using a lumped inelasticity analytical model. In addition, modifications to a standard degrading stiffness hysteretic model were proposed to account for accumulated damage due to repeated testing. Satisfactory agreement between the SDOF-predicted and experimentally recorded maximum displacements, time to maximum displacements, and residual displacements were obtained.