Loss-of-stability induced progressive collapse modes in 3D steel moment frames

Abstract

This paper deals with the progressive collapse analysis of a tall steel frame following the removal of a corner column according to the alternate load path approach. Several analysis techniques are considered (eigenvalue, material nonlinearities, material and geometric nonlinearities), as well as 2D and 3D modelling of the structural system. It is determined that the collapse mechanism is a loss-of-stability-induced one that can be identified by combining a 3D structural model with an analysis involving both material and geometric nonlinearities. The progressive collapse analysis reveals that after the initial removal of a corner column, its two adjacent columns fail from elastic flexural-torsional buckling at a load lower than the design load. The failure of these two columns is immediately followed by the failure of the next two adjacent columns from elastic flexural -torsional buckling. After the failure of these five columns, the entire structure collapses without the occurrence of any significant plastification. The main contribution is the identification of buckling-induced collapse mechanisms in steel frames involving sequential buckling of multiple columns. This is a type of failure mechanism that has not received appropriate attention because it practically never occurs in properly designed structures without the accidental loss of a column.

Progressive collapse mitigation of 2D steel moment frames

“…For this type of structure, the strengthening techniques must focus on critical key column elements that are prone to fail through buckling rather than horizontal elements that can be used through membrane or catenary action. Another important point made is that the only way to capture such a loss-of-stability-induced failure is to perform an analysis involving material and geometric non-linearities [18]. Combining the findings from [18] and the present study, the following general guidelines can be provided:…”

“…Another important point made is that the only way to capture such a loss-of-stability-induced failure is to perform an analysis involving material and geometric non-linearities [18]. Combining the findings from [18] and the present study, the following general guidelines can be provided:…”

“…The in-section integration scheme allows one flange of the section to enter the hardening zone before the rest of the section, thus producing the potential inelastic loss-of-stability phenomenon. As has been shown in a previous paper by the authors [18], the only method of analysis able to capture this phenomenon is a material and geometric non-linear method with imperfections, coupled with the in-section integration feature. It should also noted here that the frame joints are simulated with the rigid body constraint of ABAQUS, taking into account the section overlapping of the beam elements and the beamcolumn connections as rigid.…”

“…The present paper utilizes the findings included in [17] and [18], comprehensively examines the instability of 2D steel frames when exposed to progressive collapse and investigates the effect of different strengthening schemes on the progressive collapse capacity of a structure.…”

00.02: Developments in research and assessment of steel structures: Highlights from the perspective of an American researcher

“…However, Gerasimidis and his colleagues, Fig. 10, have been developing a comprehensive approach to assessing stability-based limit states in progressive collapse as well [88,89].…”