An experimental investigation on the characteristics of tension lap splice in UHPFRC beams

The current study aims to evaluate the features of the tension lap splice in ultra-high-performance fiber-reinforced concrete (UHPFRC) beams. An experimental program was conducted to investigate the flexural behavior of UHPFRC beams with various lap splice lengths. According to UHPFRC design recommendations and current code provisions, the minimum effective lap splice length and validation of the safety of lap splice length design recommendations were studied. A flexural test was performed on 15 UHPFRC beams that were prepared and configured to fail. One beam was used as a control without a lap splice, the other beams were tested with suggested splice lengths of 10, 20, and 30 times the bar diameter based on UHPFRC design recommendations. A four-point loading scheme with a shear span-to-depth ratio of 2.0 was used to test all beams. The experimental findings demonstrated that the Japan Society of Civil Engineers' (JSCE) splice length formula (≥ 20ϕ) was adequate to achieve steel rebar yielding and exhibit ductile behavior in UHPFRC beams. Based on the evaluation results, in the case of utilizing hooks at the splice ends, the short splice length of 10ϕ proposed in this paper was sufficient to achieve reinforcement yield stress and maximum ductility when compared to a beam without splice and therefore recommended in UHPFRC.