Impact of seismic retrofitting on progressive collapse resistance of RC frame structures

Most of the existing buildings in seismic prone regions have been built before publication modern design provisions against earthquakes, resulting need for structural retrofitting. Furthermore, some those are also subjected to additional hazards that may be either triggered by earthquakes (e.g., landslides, soil liquefaction, tsunamis) or associated with other natural anthropogenic events, such as floods, vehicle collision, blast, and fire. A multi-hazard performance assessment building structures is thus paramount importance implement integrated retrofit strategies, which otherwise would not economically sustainable if oriented risk mitigation a single hazard. While strategies improve reinforced concrete (RC) widely investigated, retrofitting progressive collapse has received very little attention. Within this context, present paper illustrates numerical investigation on influence robustness four-storey, five-bay, RC frame designed only gravity loads. Seismic were respectively evaluated OpenSees through pushover pushdown analyses fibre-based finite element model. Structural was under two relevant column-removal scenarios, i.e., sudden loss central corner column, whereas earthquake resistance assessed according N2 method, evidencing measure based carbon fibre polymers then considered avoid premature brittle failures. Analysis results show strategy able increase both safety robustness. Subsequently, parametric analysis carried out order evaluate impact beam span length shear strength system.