Flexural behavior of brittle RC members rehabilitated with concrete jacketing

The composite flexural action of prismatic reinforced concrete (RC) members repaired/strengthened by RC jacketing was modeled with a dual-section approach. The model considers the relative slip at the interface between the existing member and the jacket and establishes the mechanisms that are mobilized to resist this action, thereby supporting composite behavior. An iterative step-by-step incremental algorithm was developed for calculating the overall flexural response curve. Consideration of frictional interlock and dowel action associated with sliding at the interfaces as well as the spacing and penetration of flexure-shear cracks are key aspects of the algorithm. The proposed procedure was verified through comparison with published experimental data on RC jacketed members. The sensitivity of the upgraded member's flexural response to jacket design variables was investigated parametrically. Monolithic response modification factors related to strength and deformation indices were evaluated and the sensitivity of the model was assessed.