LIMITATIONS OF EUROCODE 8 DUAL DUCTILITY CLASS APPROACH IN SEISMIC DESIGN OF RC HIGH-RISE BUILDINGS

摘要

The paper contains a discussion of limitations of dual ductility class approach in seismic design of reinforced concrete (RC) high-rise buildings designed according to Euro-code 8. An extensive study is performed in order to examine the applicability of Eurocode 8 provisions related to ductility classes for seismic design of RC walls in high-rise buildings. As representative buildings, 20-storey, 30-storey and 40-storey RC high-rise buildings with core wall structural system are selected. For the purposes of the conducted study, nonlinear time-history analyses are performed for 60 ground motion records with a wide range of magnitudes, distances to source and various soil types. Design seismic shear forces obtained by Eurocode 8 for medium and high ductility classes are analyzed and compared with the real shear forces obtained by nonlinear time-history analyses. The current Eurocode 8 provisions for calculating seismic design shear forces in RC walls yields significantly incorrect results when it is applied to RC walls of high-rise buildings. The results derived in this study indicate that RC high-rise buildings should be designed according Eurocode 8 provisions specified for medium ductility class, taking into consideration the weakness of the existing procedure for calculating design shear force. The need of introducing a single ductility class for RC high-rise buildings is pointed out.