Title:
Lap Splices of Bars in Bundles
Author(s):
John Cairns
Publication:
Structural Journal
Volume:
110
Issue:
2
Appears on pages(s):
183-192
Keywords:
bond strength; brittleness; bundles; lap splices
DOI:
10.14359/51684399
Date:
3/1/2013
Abstract:
European (EC2) and ACI 318-08 design code rules for lap splices of reinforcing bars within a bundle differ markedly—the former permits the same or shorter lap-splice lengths with respect to splices of individual bars, while the latter requires longer laps. This paper reports an investigation into the performance of lap splices of individual bars within a bundle of two or three. The results show that the bond strength of individual bars is not reduced on account of their forming part of a bundle (contrary to the provisions of ACI 318-08). Staggered laps were found to be weaker but fail in a less brittle manner when splices are staggered longitudinally as compared to equivalent laps, in which all bars are spliced at the same section whether or not bars were bundled. Therefore, the outcome raises the question of the validity of reductions permitted by both the ACI 318-08 and European (EC2) codes, where only a portion of the bars is lap-spliced at a section. It is recommended that further investigation of the influence of the proportion of bars lapped at a section on splice performance be undertaken.