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Progressive collapse vulnerability of 3D high rise steel buildings under external blast loading

Extreme hazard loads may occur during the service life of existing structures. The capacity of these structures to successfully absorb such abnormal loads, known as robustness, is in most cases not considered in their design. The recent terrorist attacks of the Alfred P. Murrah Federal Building (1995) and World Trade Center (2001) have attracted the universal interest of building control authorities to develop guidelines and provisions for mitigation of such events. In the same environment, extensive research from the structural engineering community has focused on the progressive collapse of multi-story buildings initiated by blast and impact loading. The main objective of progressive collapse analysis is the assessment of vulnerability of structural systems to localized damage and the design of structures that are able to absorb initial damage by not allowing the triggering of a wider collapse mechanism. This paper presents a study of the effect of near field explosions on the structural integrity of high rise steel buildings. Numerical simulation employing 3D nonlinear finite element techniques is used to examine the spatially distributed response and damage to frame members along the building exterior facing an external blast. The complex nonlinear dynamic system results in the heavily impacted region are compared to a simplified analytical approach consistent with current design recommendations. Parameters affecting the spatially distributed pressure and response quantities are also identified, as well as their effect on the progressive collapse vulnerability for the blast scenarios considered.

Author(s):

Jenny Sideri    
Columbia University
United States

Christopher Mullen    
University of Mississippi
United States

Simos Gerasimidis    
Columbia University
United States

George Deodatis    
Columbia University
United States