ENHANCEMENT OF TENSION LAP SPLICE IN HPC USING DIFFERENT TECHNIQUES

High Performance Concrete (HPC) with favorable material properties has been commonly used in different reinforced concrete projects such as bridges, tunnels, tall buildings and parking garages. Due to the limited lengths of manufactured reinforcement steel bars, splicing of these bars is urgently required for long span structures. Since lap splice is considered as the most economic and the easiest way for linking reinforcement steel bars, an experimental study on 21 lap splices embedded in HPC specimens was performed under direct tension test. Five different techniques were employed for straight and anchored bars with several splice lengths in order to obtain the minimum lap splice length for transferring the design force of the bars. For straight bars, spiral confinement with either inner or outer linking bars was used. On the other hand, for anchored bars, hooks, hooks with cross bars and end bearing plates were used. It was found that a splice length of 10 db was sufficient to achieve nominal yield stress of reinforcement in case of using spiral confinement with inner linking bars. On contrary, 5 db length of splice was found enough for all anchored bars to achieve their design force.