Robustness of steel moment frames in multi-column-removal scenarios

This paper presents a numerical study on the performance of the multi-storey steel frame in sudden multi-column-removal (MCR) scenarios. The reliability of the numerical analyses are initially validated against experimental results. The effects of the removed column number, column location and magnitude of the applied load on the robustness of the frame are discussed. Results from numerical analyses can provide references to the collapse-resistant design of steel frames in the following two aspects. The one is the allowable maximum number of failure columns in robustness assessment of the steel frame. The other is the typical column-removal scenarios which should be particularly considered in practical design. It is found that for steel moment frame with design loads, it will collapse in some four-column-removal scenarios. Hence four-column-removal scenarios should be avoided by taking certain construction measurements in practical design. Two and three-column-removal scenarios should be particularly considered when assessing the robustness of the frame. For steel moment frame with twice design loads, the frame will collapse in any two-column-removal scenarios. Moreover, in small load case, the frame has the greatest robustness due to corner-column-related losses. While in large load case, the robustness of the frame is the strongest in interior column losses. The linearly consecutive column losses have less adverse effects on the robustness of the frame than the rectangular-shaped column-removal scenarios.