Analytical assessment of steel frames progressive collapse vulnerability to corner column loss

• Progressive collapse modes of steel frames for corner column removal
• Column buckling and yielding‐type initiated progressive collapse
• Analytical method for the vulnerability assessment of damaged systems
• Sensitivity analysis of regular and vertically irregular steel frames
• Threat‐independent analytical method for progressive collapse of steel frames

Most of the approaches to the progressive collapse analysis of steel frames have focused so far on computational methods which try to capture the solution of the system responding to localized damage. For the case of progressive collapse, damage is included in the model through the removal of a key element of the structure. The computational difficulty of these approaches, however, makes it very hard for practicing engineers to perform these analyses. For that reason, it is very important for the engineering community to develop simple and reliable analytical tools which could provide useful information on the response of a structure to a column loss. This paper applies a threat-independent analytical method regarding the corner column loss case, which has been presented by the author in previous papers to a wide range of symmetric and non-symmetric steel moment-resisting (sway) frames. The analytical and simple method can indicate the collapse mechanism of a steel frame for the case of a corner column loss through the development of critical ductility curves. The impact of the number of floors, the column removal location, the vertical irregularity and the design of the frames is also studied.