Test Results and Comparison to Code Equations on Lap Splice Strength of Reinforcement in RC beams

Abstract

The design of the lap splices will have a major change with the 2nd generation Eurocode prEN 1992-1-1 D7. One of the changes in prEN1992-1-1 D7 is the effect of the proportion of the lapped bars in tension in one cross-section. In the current Eurocode, a large proportion of the lapped bars in cross-section has led to a 1.5-fold lap length when comparing to anchorage, while, in prEN1992-1-1 D7, the lap length is in many cases similar to the anchorage length. Questions have arisen about the strength and ductility of the member with lap splices. As a result, there is a need to have more experimental evidence of the behaviour of the lapped joints and, in particular, if they are placed near the plastic hinges. In this context, this paper is part of a research project that aims to gain more information on the behaviour of the lapped bars in RC beams. This paper focuses on the effect of the lap length on the lap strength, while the latter part of the study deals with the lap splice ductility. Test specimens were beams with a square cross-section, which were reinforced with four rebars on the tension side and they were tested under four-point bending conditions. The rebar size, lap length and proportion of the lapped bars were varied between the specimens. The lap length in the test beams was 20-60 times the bar diameter. The results of the loading tests were compared to the code type models. Information was obtained on the lap strength and precision of different code models.