Robustness Assessment of RC Frame Buildings under Column Loss Scenarios

A computational assessment of the robustness of reinforced concrete (RC) building structures under column loss scenarios is presented. A reduced-order modeling approach is presented for three-dimensional RC framing systems, including the floor slab, and comparisons with high-fidelity finite element model results are presented to verify the approach. Pushdown analyses of prototype buildings under column loss scenarios are performed using reduced numerical models, and an energy-based procedure is employed to account for the dynamic effects associated with sudden column loss. The load-displacement curve obtained using the energy-based approach is found to be in good agreement with results from direct dynamic analysis of sudden column loss. A metric for structural robustness is defined by normalizing the ultimate capacity under sudden column loss by the applicable service-level gravity loading. The procedure is applied to two prototype, 10-story RC buildings, one employing intermediate moment frames (IMFs) and the other employing special moment frames (SMFs). The SMF building, with its more stringent seismic design and detailing, is found to have greater robustness.