Lap splices in confined self-compacting lightweight concrete

This paper presents an experimental investigation on the behaviour of spirally confined lap splices of deformed steel bar in self-compacting lightweight concrete (SCLWC). A total of twenty-four specimens were divided into three series and tested under tension. The difference among each series is the splicing details and configuration for each specimen. The parameters included to study the bond behaviour of SCLWC was bar diameter, lap length, and number of spirals. The experimental results include the ultimate load and bond stress along with cracking behaviour and failure mode of the specimens. A typical failure mode was observed for all specimens, which started after yielding of the steel bar. Proposed confinement details improved post-cracking behaviour and played a vital role in delaying and widening the cracks. The results showed that majority of the specimens achieved axial stress higher than the yield stress of the bar. The lap length for steel bars with diameter of 12 mm, 20 mm, and 25 mm can be used as short as 127 mm in confined SCLWC. In addition, the estimated development length based on different concrete design codes was compared with the experimental results. The results indicated that the codes included in the study have overestimated the development length and CSA-2014 code was the least conservative among all the other codes.