1 Proposed EN 1992 tension lap strength equation for good bond Robert Vollum 1 *, Charles Goodchild 2 1. Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK 2. The Concrete Centre, Gillingham House, 38-44 Gillingham Street, London, SW1V 1HU * Corresponding author, r.vollum@imperial.ac.uk Abstract The paper is concerned with the design of tension laps in reinforced concrete structures. The most recent codified design recommendations for reinforcement laps and anchorages are found in fib Model Code 2010 (MC2010). These recommendations have heavily influenced the draft revision of EN 1992 which is due for publication in 2023. The draft EN 1992 proposal for tension laps is still under development with the main point of discussion being the basic multiplier required to achieve the level of safety prescribed by EN 1990. This is contentious since laps designed to MC2010 can be significantly longer than laps designed to EN 1992 (2004) which many UK designers consider excessive in comparison with previous UK practice. The paper examines the safety of tension laps and proposes a refined design equation for inclusion in the 2023 revision to EN 1992. The proposed design equation achieves the level of safety required by EN 1990 whilst giving lap and anchorage lengths more consistent with current practice than MC2010. Keywords Reinforced concrete design, tension laps, Eurocode 2 1 Introduction EN 1992 (2004) [1] is undergoing a substantial revision which is due to be published in 2023. The draft revision of EN 1992 [2] includes lap and anchorage rules based on the recommendations of fib Bulletin 72 [3] and fib Model Code 2010 (MC2010) [4]. By way of background, MC2010 requires significantly longer laps than EN 1992 (2004) [1], which Cairns and Elighausen [5] showed to have less than the expected margin of safety. Any increase in lap lengths is of concern to UK engineers who already find that the reinforcement detailing requirements of EN 1992 complicate construction and increase project costs compared with previous UK practice [6, 7]. The introduction to the paper describes the design provisions for tension laps in EN 1992, fib Bulletin 72 and MC2010. Subsequently, it describes a reliability analysis carried out by Mancini et al. [8] to determine a suitable safety format for the design of tension laps using equation 3-2 of fib Bulletin 72. The reliability based method of Mancini et al. [8] is used to develop a refined design equation for