Structural rehabilitation of half-joints in RC bridges: a state-of-the-art review

Gerber road bridges provide clear advantages in terms of stress distribution and absorption of small settlements. For this reason, such bridge designs have been frequently used in Italy and abroad. This static arrangement is provided with connections among spans located in the half-joints, which are prone to the accumulation of deteriorating agents and are difficult to inspect. Furthermore, these bridges were designed based on old code provisions referring to loads lower than those prescribed by current codes. Hence, half-joints frequently need to be assessed and possibly strengthened. This paper reviews the available strengthening techniques based on both practice and experimental results, comparing them in terms of structural performance, failure mode and governing limit state. As result, a decision-making approach is proposed in order to guide intervention choices while accounting for design requirements and constraints. In fact, the presence of curbs and transverse beams close to half-joints prevents the utilization of externally bonded composites making steel-based techniques more suitable. Some remarks on intervention costs highlight the great impact of deteriorated half-joints due to the need for bridge lifting and carry out restoration interventions. Therefore, the need for repair should be carefully evaluated as it significantly influences the overall intervention cost.