A SIMPLE DISPLACEMENT COMPATIBILITY-BASED SEISMIC DESIGN STRATEGY FOR REINFORCED CONCRETE BUILDINGS

Recent studies provided an opportunity to review some of the principles, which have been used in the formulation of internationally accepted code recommendations relevant to the seismic design of buildings also subjected to torsional phenomena. In the context of specific design criteria this review led to definitions of strength, element and system yield displacements and hence relevant stiffness. A liberal strategy in the assignment to lateral force resisting elements of strength, very different from that based on traditionally defined stiffness, is postulated. This necessitates an examination of displacement compatibility criteria applicable to ductile mixed structures subjected to uniform translations. Applications of the findings are illustrated. The relevance of displacement compatibility for the ultimate limit state is extended to address also systems in which, due to static and dynamic torsional phenomena, element displacements, and hence displacement ductility demands, may be different. Only design and behaviour oriented simple concepts, combined with static and dynamic equilibrium criteria, are used to encourage designers to impart desirable properties to structures, which may be subjected to significant earthquake induced displacements.