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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.

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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.

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In this study, the seismic design and performance of composite steel-concrete frames are studied. The new Eurocode 4 and Eurocode 8, which are in a preliminary stage at the moment, are employed for the design of six composite steel-concrete frames. The deficiencies of the codes and the clauses that cause difficulties to the designer are discussed. The inelastic static pushover analysis is employed for obtaining the response of the frames and the overstrength factors. The evaluation of the response modification factor takes place by performing incremental time-history analysis up to the satisfaction of the yield and collapse limit states in order to investigate the conservatism of the code. The last purpose of this study is to investigate if elastically designed structures can behave in a dissipative mode.

A methodology for design and proportioning of interventions for seismic upgrading of substandard reinforced concrete (RC) buildings is developed in this paper. The retrofit approach is presented in the form of a simple design tool that aims at both demand reduction and enhancement of force and deformation supply through controlled modification of stiffness along the height of the building. This objective is achieved by engineering the translational mode-shape of the structure so as to optimize distribution of interstorey drift.Results from the proposed approach are summarized in a spectrum format, where demand expressed in terms of interstorey drift is related to stiffness. Design charts, which relate the characteristics of commonly-used global intervention procedures to influence drift demands are developed to facilitate the retrofit design. Intervention procedures considered in this paper are reinforced-concrete jacketing, addition of reinforced concrete walls, and addition of masonry infills. The proposed methodology is also amenable to adaptation to other strengthening methods such as addition of cross-bracing and others.