Accounting for Resilience in the Selection of R Factors for a RC Unsymmetrical Building

Several design codes consider the non-linear response of a building by using one of the most im-portant seismic parameters, called the response reduction factor (R). The lack of a detailed de-scription of the R factor selection creates the need for a deeper study. This paper emphasises a methodology for the selection of a proper R factor based on resilience aspects. Unsymmet-rical/irregular buildings have become the most common in recent times due to aesthetic purposes. However, because of the complexity due to the torsional effect, the selection of the R factor is even more difficult for this type of building. Therefore, a high-rise G+10-storey L-shaped building is herein considered. The building has re-entrant corners based on the structural/plan arrangement. Different R factors were used in the building design, and they were subjected to both unidirec-tional and bidirectional seismic loading scenarios. The building response with respect to various R factors (R equal to 3, 4, 5 and 6) in terms of its performance level, functionality, damage ratio and resilience was assessed at two design levels, i.e., design basic earthquake (DBE) and maxi-mum considered earthquake (MCE). The study concludes that, considering the above criteria along with the resilience aspect, a maximum R factor up to 4 can be recommended for unidirec-tional loading, whereas for bidirectional loading, the maximum recommended R factor is 3.