Multi-hazard performance assessment of reinforced concrete frame structures subjected to earthquakes and wind loads

Reinforced concrete (RC) frame structures are subjected to both earthquakes and wind during their service life. However, existing studies rarely address low‑rise RC frames under combined wind-seismic excitations. To fill this gap, we analyze a six‑story RC frame under 100 randomly combined scenarios (10 ground motions × 10 wind speeds) using nonlinear time‑history analysis, comparing uncontrolled and viscous‑damper‑retrofitted configurations. Results show that combined excitation substantially amplifies displacement compared to isolated loads. Under a PGA of 0.159 g and a 16 m/s wind, the top‑story displacement increases by 9.8% relative to the earthquake alone and by 364% relative to wind alone. The proposed damper scheme reduces structural response across all scenarios (9.5-26.9% reduction) and lowers the exceedance probability at the severe damage limit state by up to 42.4% points. After retrofitting, the structure's sensitivity to seismic intensity decreases by 27.4%. These findings demonstrate that single‑hazard assessments underestimate actual risks for low‑rise RC frames in windy regions. The proposed damping strategy offers a practical pathway to enhance multi‑hazard resilience.