Seismic damage mitigation strategy using an FRP column jacketing system in gravity-designed reinforced concrete building frames

Abstract

Many existing reinforced concrete building structures designed for gravity loads have seismic vulnerabilities owing to their deficiency in column detailing. A column jacketing system with prefabricated fiber-reinforced polymer materials provides additional confinement and stiffness to existing columns and mitigates their seismic vulnerabilities. This paper presents a seismic retrofit strategy for a low-rise gravity-designed reinforced concrete building frame for maximizing the retrofit effect against low, moderate, and high seismic hazard levels. The retrofit parametric models were created by varying the confinement and stiffness-related parameters and then simulated under various seismic loading scenarios. To establish the seismic strengthening strategy, the effectiveness of the retrofit system was examined in terms of its confinement and stiffness-related parameters. This retrofit effect was computed by comparing energy-based seismic demands between retrofitted and nonretrofitted models. Based on the parametric analysis, the critical parameters of the retrofit system were determined depending on the seismic hazard levels. Thus, the certain threshold values of the retrofit parameters for the seismic hazard levels to maximize the effectiveness of the retrofit system were proposed as the retrofit design scheme.