Computational assessment of the progressive collapse of a five storey structure considering two different building codes

Abstract

The analysis and understanding of the progressive collapse of buildings plays significant role on the search for structural safety. The present work proposes the association of a corotational formulation, plasticity and a sectional degradation model for the analysis of reinforced concrete (RC) buildings designed in accordance to fib [1] and Eurocode [2] and also the Brazilian building code (ABNT - NBR 6118) [3]. The model makes use of a layered Euler/Bernoulli-based beam formulation and takes into account both nonlinear and dynamic aspects. The corotational formulation used for including geometrical nonlinearities is similar to the one proposed in [4]. The material nonlinearity is based on a one-dimensional elastoviscoplastic model. A sudden column loss approach is considered, turning the formulation into a general one for dynamic analysis of planar RC frames. Also, by discretizing the transversal section into layers, it is possible to tackle the problem in a multiscale approach [5]. The chosen structures intentionally assume the minimum requirements for the design of multi-storey edifices that are proposed by fib [1]-Eurocode [2]and ABNT - NBR 6118[3], being used to verify if these requirements are sufficient for enforcing structural safety and also to verify the major differences between those two building criteria concerning progressive collapse.