Proceedings home preface contents authors keywords copyright reference ©2012 Civil-Comp Ltd				Paper 244 Progressive Collapse Risk and Robustness of Low-Rise Reinforced Concrete Buildings L. Bredean, M. Botez and A. Ioani Department of Structural Mechanics, Faculty of Civil Engineering, Technical University of Cluj-Napoca, Romania Keywords: progressive collapse potential, seismic design, low-rise buildings, demand capacity ratio. full paper (pdf) - reference In this paper results concerning the progressive collapse potential of low-rise reinforced concrete structures are presented. Low-rise structures with three and six floors were designed according to the provisions of Eurocode 2 [1] and P100-1/2006, the active Romanian Seismic Code [2], for a low and a high seismic zone. The particular behaviour of low-rise buildings in comparison with similar located mid-rise buildings is discussed. Applying four damage scenarios, as specified in the GSA (2003) Guidelines [3], demand capacity ratio (DCR) values for flexure are computed for each model. The main objectives of the study and corresponding findings are presented as follows: The effect of prescribed damage scenarios on progressive collapse potential: For a given model, the magnitude of maximum inelastic demands only slightly differs when different "missing column" scenarios are considered, and consequently, the final conclusion concerning the risk level was the same; This finding is original and highly valuable because, on its basis, the final conclusion regarding the progressive collapse potential of a building could be drawn by investigating only one damage scenario instead of four. The general progressive collapse behaviour of low-rise reinforced concrete framed structures versus mid-rise structures: Low-rise buildings present a higher risk of progressive collapse compared to mid-rise buildings. The influence of the floors number on the robustness of low-rise structures: The robustness of low-rise buildings located in low seismic zones is not significantly affected by the number of storeys; On the contrary, if the building is designed for a high seismic zone, its robustness strongly depends on the number of floors; The progressive collapse risk decreases when the number of stories increases. The influence of the seismicity of the area: For the first time in the technical literature, the paper illustrates in a quantitative manner, differentiated with respect to the number of storeys, the positive effect of seismic design and detailing on the progressive collapse resistance of reinforced concrete framed structures. References 1 SR EN 1992-1-1: 2004, "Eurocode 2: Design of Concrete Structures - Part 1-1: General Rules and Rules for Buildings", ASRO, Bucharest, 2004. (in Romanian) 2 P100-1/2006, "Seismic design code - Part I: Design Rules for Buildings", MTCT, Bucharest, 2006. (in Romanian) 3 U.S. General Service Administration, "Progressive Collapse Analysis and Design Guideline for New Federal Office Buildings and Major Modernisation Projects", Washington D.C., June 2003.