Forensic assessment of deteriorated reinforced concrete half joints through nonlinear finite element analysis

Reinforced concrete half‑joints are vulnerable to reinforcement corrosion, bond deterioration, and localised concrete damage, much of which often develops within concealed regions of the joint. These forms of deterioration can disrupt internal load-transfer mechanisms and lead to brittle, potentially catastrophic failure. In this paper, a nonlinear finite element analysis framework was validated against a comprehensive experimental programme on half-joints incorporating representative deterioration scenarios, and used to investigate the influence of reinforcement cross-sectional loss and bond degradation. The results show that the analyses were able to reproduce the experimentally measured load–deflection responses, crack patterns, and failure locations of the half-joint specimens with good accuracy. Reductions in reinforcement at the re‑entrant corner were identified as the primary cause of capacity reduction, while anchorage deterioration and reductions in shear links altered the governing failure mode and internal load paths. When multiple forms of deterioration were present, the resulting reduction in capacity became nonlinear and was further exacerbated by reductions in concrete strength. Evaluation of reinforcement stresses and principal concrete compression fields provided insight into both the redistribution of internal forces caused by local deterioration and the mechanisms underlying the observed failure crack patterns. Overall, the results indicate that nonlinear finite element analysis can serve as a valuable forensic and predictive tool to support the inspection and assessment of deteriorated half-joints.