Long‐term performance of single‐lap joints: Review, challenges and prospects in civil engineering

Abstract Compared with traditional technology, bonding technology is more suitable for civil structure reinforcement because of its cost‐efficiency and superior mechanical properties. However, research on the long‐term performance of single‐lap joints (SLJs) requires better organization and comprehension. This article aims to investigate the long‐term performance and optimization design of SLJs. The main factors influencing the long‐term performance of SLJs from both material and component levels are discussed. The moisture diffusion mechanisms of bulk adhesives and the degradation mechanisms of SLJs are explored. Moreover, the optimization design of SLJs focuses on evaluating the overlap length, adhesive layer thicknesses, and changes in adhesives along the overlap length based on available literature. It is found that the applicability of diffusion models should be validated, and the selection of the models should consider working environments and types of adhesives. Exploring failure mechanisms and design criteria for the mixed SLJs in hygrothermal environments with/without sustained or alternating load is significant for the optimization design. This article indicates the limitations on the shear strength and long‐term performance of SLJs in available studies and provides insights into the challenges and prospects of their optimization design.