A Performance-Based Seismic Design Procedure for 3D R/C Buildings, Explicitly Accounting for Deformation Control

A deformation-based design method concerning 3D reinforced concrete (R/C) buildings is presented, which involves response-history analysis for multiple levels of earthquake action, using a partially inelastic model; the design of structural members is carried out for different performance levels related to their inelastic behaviour. A new procedure for the design of members that are expected to develop inelastic behaviour for the serviceability earthquake is proposed, wherein the deformation limits for the specific performance level, which are related to the degree of damage in the structural members, are fully exploited. The proposed method is applied to irregular multistorey R/C 3D frame buildings with setbacks (also designed to Eurocode 8), and their performance for several levels of earthquake action is assessed using a fully inelastic model and additional ground motions (not used at the design stage). Comparison of the two methods of seismic design reveals the advantages of the proposed design method, in particular the more economic detailing of transverse reinforcement in members that develop very little inelastic behaviour.