Civil Engineering Association

NONLINEAR ANALYSIS FOR A REINFORCED CONCRETE FRAME STRUCTURE UNDER EXTREME LOADS

Terrorist actions of the last decade obviously determine a reconsideration of the buildings safety, especially for those with special destinations (embassies, military facilities, nuclear plants etc.). Thus, the conception phase should include nowadays scenarios with exceptional actions, other than seismic loads:
impact, explosion, failure of supports. It is well-known that, after earthquakes, the most situations of structural collapse are determined by the terrorist attack using explosive. Even
more, it has been assessed that the main reason of loss of life is not the explosion itself, but the partial or total collapse of the exposed building. In order to secure the structural integrity,
collapse analysis should be taken into account as a complex phenomenon, composed of many processes that could be studied separately or as an ensemble. These processes are: the extreme action causes, design requirements, vulnerability
of the structure, starting and development of the collapse, its final effects. Study of these processes leads to additional special measures for design stage and, on the other hand, to valuable knowledge for controlled demolition of tall buildings, as part of bold urbanism projects in densely populated zones. Considering the above mentioned facts, this paper presents the results of a thorough analysis of a frame structure under explosive loads. The first part of the paper refers to the analysis of a phenomena assembly related to explosion and to the effects resulting from a terrorist attack using explosives (structural elements deterioration and failure, collapse initiation and eventual total failure). The second part of the paper presents an original approach to analyze a building structure
under extreme loads, using both classical (pushover) and modern (applied element method).