A deformation-based seismic design method for 3D R/C irregular buildings using inelastic dynamic analysis

摘要

A new deformation-based design method concerning 3D reinforced concrete (R/C) buildings is presented, which involves the use of advanced analysis tools, i.e. response-history analysis for appropriately scaled input motions, for multiple levels of earthquake action. The critical issues concerning the inelastic response-history analysis used for the design, namely the definition of the appropriate input, the set up of the analytical model that should account for post-yield behaviour of plastic hinge zones, and the direction of loading, are discussed. The proposed method is based on a partially inelastic model, while the design of structural members is carried out for different performance levels related to their inelastic behaviour. The aforementioned method builds on previous proposals by the first author and his co-workers, nevertheless a new procedure for the design of members that are expected to develop inelastic behaviour for the serviceability earthquake is proposed; its aim is the reduction of member design forces and the a-priori definition of their inelastic performance, by exploiting the deformation limits for the specific performance level, which are related to the damage level of the structural members. The proposed method was applied to irregular multistorey R/C 3D frame buildings with setbacks, and their performance for several levels of earthquake action was assessed using a fully inelastic model and additional ground motions not used at the design phase. The same buildings were designed according to the provisions of Eurocode 8. Comparison of the two methods of seismic design, revealed the advantages of the proposed design method, in particular the more economic detailing of transverse reinforcement in the members that develop very little inelastic behaviour even for very strong earthquakes.