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.

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SummaryA review of repair schemes for reinforced concrete frame buildings is presented in this paper, within the context of global objectives of the intervention process. Local as well as global intervention measures are discussed and their technological application details outlined. The effect of the reviewed repair schemes on the member, sub-assemblage and system performance are qualitatively assessed. The important role of the foundation system in the rehabilitation process is outlined and measures that are consistent with the super-structure intervention methods are given. The paper concludes with a global assessment of the effect of repair methods on stiffness, strength and ductility, the three most important seismic response parameters, to assist researchers and practitioners in decision-making to satisfy their respective intervention objectives. The framework for the paper complies with the requirements of consequence-based Engineering, where the expected damage is addressed only when consequences are higher than acceptable consequences, and a cyclical process of assessment and re-assessment is undertaken until the community objectives are deemed to be satisfied.

This paper is a comprehensive background document on the state of the art in European seismic design provisions which was assembled by fib committee 5.1 to support the development of design guidelines regarding the use of externally applied fibre reinforced polymer (FRP) materials in the seismic retrofitting of reinforced concrete structures. In the context of developing design guidelines, the underlying mechanistic models that support the derivation of provisions were assembled following critical evaluation of the existing proposals and with careful reference to the experimental evidence available, the comparative assessment of past models in the literature and requirements established from first principles.