Abstract:In order to study the progressive collapse behavior of steel frame structures under the action of environmental erosion, a steel corrosion model was developed to predict the changes of the cross-sectional area and mechanical properties of the members with their service time. A multi-story steel frame structure in a Class III atmospheric corrosion environment is studied and the Pushdown analysis is performed at different stages of its full life cycle. The results show that corrosion causes degradation of the bearing capacity and ductility of steel frames, especially on ductility degradation. The influences of different material parameters on the resistance index against progressive collapse are obtained by sensitivity analysis. The degradation of bearing capacity is mainly attributed to the reduction of material strength and cross-sectional area of the members. The decrease of ductility index is attributed to the degradation of steel elongation. Finally, the variation rules of resistance index with volume loss rate are obtained based on regression analysis.