Progressive collapse of steel frame-brace structure under a column-removal scenario

Abstract

Progressive collapse attracted more attention of researchers in recent years, mainly due to the increasing number of terrorist incidents worldwide. Based on the GSA and DOD design guidelines, structural resistance mechanisms to progressive collapse of steel frame, V-shaped and X-shaped braced frame structures are studied by a comparative analysis. The results show that the robustness index (RI) of steel braced frame structure is significantly greater than steel frame structure, and the X-shaped brace is greater than the V-shaped brace. Furthermore, static pushdown and nonlinear dynamic analysis are performed to study dynamic effects attributed to a column removed. The results show that the ultimate failure modes are generally similar by these two analytical method. The presence of the column bracing reduces the dynamic displacement response for a column removed instantly, and the X-shaped brace is better than the V-shaped brace.