High ductility seismic performances of wide-beam RC frames

Italian and Spanish seismic codes, conversely to Eurocode 8 and other relevant seismic codes worldwide, consider that wide-beam RC frames (WBF) cannot guarantee high ductility performances, thus they compel to adopt lower behaviour factors (q) than for conventional deep-beam frames (DBF). The reason may be the poorer local ductility of wide beams with respect to deep beams, together with an historical lack of confidence on WBF regarding force transfer within connections and higher lateral deformability. Aimed at verifying the appropriateness of such provisions, seismic performances of a typical Mediterranean 5-storey RC building designed alternatively with DBF and WBF according to Eurocode 8 and Spanish NCSE-02 are comparatively assessed through nonlinear static analyses. Later, a simplified parametric assessment is carried out for 72 frames designed to Eurocode 8, Italian NTC and NCSE-02 assuming similar q for WBF and DBF. Results suggest that WBF provide at least similar global seismic capacities than DBF, especially in frames whose design is ruled by damage limitation limit state. Hence, any reduction of qfor wide-beam frames in modern national codes appears to be at least obsolete.