Modelling the load-deformation behaviour of lap splices with the Tension Chord Model

Lap splices are part of virtually every structure made of reinforced concrete. As loads need to be transferred safely along these discontinuities, numerous studies focused on their strength. However, even though they are traditionally placed also in highly loaded regions of elements, which are potentially undergoing plastic deformations, little attention has been paid to their load-deformation behaviour and deformation capacity. This study presents a sound mechanical model based on the established Tension Chord Model to assess the loaddeformation behaviour of lap splices. A thorough analysis of the load transfer mechanism reveals that the major part of the load is transferred at the beginning and the end of a lap splice. Therefore, the lap splice acts as a double reinforced tensile element over a considerable length, which drastically reduces its deformation capacity to less than half of the minimum value expected for adjacent parts. This especially needs to be addressed in performance-based design methods, where the deformation demand is compared to the existing deformation capacity. The theoretical results are validated with a recently conducted experimental campaign, exhibiting excellent agreement of model and experimental data. Besides a comprehensive analysis of the influencing parameters, a simplified modelling approach for practical applications and design recommendations for new structures are presented in this publication.ISSN:0141-029