Lap-Splice Length of Bundled Glass Fiber-Reinforced Polymer Bars in Unconfined Concrete

This paper reports on the tensile lap splicing of bundled glass fiber-reinforced polymer (GFRP) bars and their bond behavior in unconfined concrete. The experimental program was comprised of 11 full-scale beam-splice tests and aimed at providing more insights into the design parameters that might affect the splice strength of bundled GFRP bars. The studied parameters included the splice length, bar diameter, and number of bars within a bundle. The results indicated that the bond strength of lap-spliced bundled GFRP bars was not linearly proportional to the splice length. Moreover, the splice strength was found to be inversely proportional to the bar diameter. In addition, the bond strength of individual bars in a bundle was lower than that of single bars. Their general behavior in terms of splice length effect, failure mode, bar-size effect, and stress distribution, however, appeared to be similar. Finally, a design recommendation is proposed based on the experimental results and observations that might provide a significant improvement in the safety level for lap-spliced bundled GFRP bars.