Behavior of Glass Fiber-Reinforced Polymer-Reinforced Concrete Columns Subjected to Simulated Seismic Load

This paper presents the results of an experimental study on concrete columns reinforced with glass fiber-reinforced polymer (GFRP) reinforcement under simulated seismic load. The investi-gation included testing of eight full-scale square concrete columns reinforced with GFRP bars, spirals, and crossties and a cross section of 400 x 400 mm (15.8 x 15.8 in.) with a total height of 1850 mm (72.8 in.). The parameters studied were the longitudinal and transverse reinforcement ratios. The columns were reinforced with 12 longitudinal bars 15.9 and 19.1 mm (0.6 and 0.7 in.) in diameter. Spirals and crossties measuring 9.5, 12.7, and 15.9 mm (0.4, 0.5, and 0.6 in.) in diameter were used as transverse rein-forcement. The specimens were subjected to cyclic lateral loading and constant axial loading of 20% of the capacity of the column. The test results indicate that the longitudinal and transverse rein-forcement ratios produced no significant changes in dissipated energy. The spacing of the lateral reinforcement influenced column strength and drift capacity at the lower longitudinal reinforcement ratio but did not significantly affect the columns at the higher longitudinal reinforcement ratio. The GFRP spirals and crossties affected the lateral strength and deformability of the column after spalling of the concrete cover. The displacement deformability index computed at a concrete compressive strain of 3000 mu epsilon showed reasonably good prediction.