Carbon Fiber-Reinforced Polymer-Strengthened Reinforced Concrete Beams Subjected to Differential Settlement

This paper presents the behavior of reinforced concrete beams strengthened with carbon fiber-reinforced polymer (CFRP) composites subjected to differential settlement. Two types of strengthening schemes-externally bonded (EB) and near-surface-mounted (NSM) CFRP-are tested with various support conditions, and their performance is compared against unstrengthened counterparts. The properties of soils are identified by sieve analysis and load-settlement relationships, including a grain distribution and subgrade reaction moduli with drained and undrained conditions. The post-yield response and energy dissipation characteristics of the beams are influenced by the differential settlement. The ductility of the strengthened beams is less susceptible to settlement in comparison with the unstrengthened ones. Regardless of support conditions, the NSM beams exhibit higher ductility than the EB beams. The development of curvature along the loading span is related to the extent of the differential settlement, which is associated with the occurrence of CFRP debonding and failure modes. Functional requirements for the strengthened beams are evaluated based on angular distortion limits. Moment redistribution mechanisms induced by the differential settlement are elaborated by analytical modeling in conjunction with parametric investigations.