Evaluation of Bundled Bar Lap Splices

Very limited data are available regarding splices and anchorage of bundled bars. ACI 318-05 prohibits splicing entire bundles, and uses multipliers to increase the required development and splice length for bundled bars to substitute for the lack of bond resistance from the core between bundled bars. The research described herein is an attempt to evaluate the behavior of bundled bar splices. Using 16 beam specimens, splices of two, three-, and four-bar bundles were compared with splices of single bars with the same cross-sectional area. Regardless of the number of bars in a bundle, splices of bundled bars had the same strength as splices of single bars with the same total bar area. The effect of development length and confinement was the same for till specimens. Specimens in which entire bundles were spliced had the same performance as equivalent single-bar specimens.