Experimental Study of Concrete Columns Reinforced with Lap-Spliced Glass Fiber-Reinforced Polymer Bars under Seismic Load

Abstract

While reinforcing bar lap splicing is inevitable in reinforced concrete (RC) structures, it critically affects structural behavior, especially in structures subjected to seismic load. That notwithstanding, current North American design standards do not provide any recommendations or equations for lap-spliced glass fiber-reinforced polymer (GFRP) reinforcing bars under seismic load. This study tested six full-scale RC columns measuring 1850 mm (73 in.) in height and 400 x 400 mm (16 x 16 in.) in cross section under constant axial load and incremental reversed cyclic lateral loading. Four columns were reinforced with GFRP bars, and two were reinforced with steel bars for comparison. The test parameters included lap-splice length and type of reinforcement. The structural performance of the specimens was evaluated based on the cracking behavior, failure mechanism, hysteretic response, load-carrying capacity, dissipated energy, stiffness degradation, and strain behavior. Afterward, available models in North American design standards for the splice length of GFRP reinforcing bars under monotonic loading were evaluated based on the experimental results. According to the results, providing adequate splice length can secure satisfactory structural performance in spliced GFRP-RC columns. The splice length determined based on the North American design standards for monotonic loading cannot, however, be directly used to achieve the required drift capacity in GFRP-RC columns under reversed cyclic lateral loading.