New Euler-type progressive collapse curves for steel frames

摘要

Progressive collapse of structures has attracted the interest of the structural engineering community starting with the Ronan Point collapse of 1968. The terrorist attacks on the Alfred P. Murrah building in Oklahoma in 1995 and on the World Trade Center in New York in 2001 further increased the research interest in this field. Progressive collapse is a phenomenon usually characterized by a triggering event of local structural failure or damage which results into partial or total collapse of the structure. In certain cases, structures have shown high levels of vulnerability to the triggering event, while in other cases they have proven to be quite resilient. The research field of progressive collapse aims at quantifying and ultimately minimizing structural vulnerabilities to a wide range of triggering events. For steel structures, the governing collapse mode usually involves the instability of a member of the structure, a part of the structure or the whole structure as a system. Previous research by the authors has shown that the response of a steel frame under a key component removal scenario can be analytically calculated. Based on this analytical methodology and similarly to the Euler curve for an individual member under compression, the paper presents new Euler-type progressive collapse curves for steel frames which can identify a short-wave loss-of-stability induced collapse mode from a yielding-type induced collapse mode. One of the main advantages of the proposed new Euler-type curves is the simple elastic analysis framework of the analytical method.