The influence of geometrically nonlinear effects on the progressive collapse of reinforced concrete structures

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Publicada em 27/02/2015

Discente: Cláudio Ernani Martins Oliveira

Resumo:

A multilayered Bernoulli beam finite element, including elasto-plastic material behavior of the constituents within a corotational, geometrically nonlinear framework is applied to investigate the behavior of reinforced concrete structures. The investigation aims at the propagation of the damage induced by the loss of a column and veries whether or not the process of progressive collapse is initiated. For the analysis, the material nonlinearity is represented using unidimensional constitutive laws in the material layers. The multilayered discretization on the sectional level allows describing the gradual crushing of concrete, as well as the yielding and breaking of the reinforcement bars. The behavior of four planar frames is investigated computationally in this work. The first structure is a intermediate moment frame (IMF), while the second one is composed of a three-storey scale model (TSM), both representing parts of two dierent buildings in a quasi-static scenario. Computational results are compared to available experimental data from the literature both in terms of structural response (load vs. displacements curves) and failure mechanisms. Catenary eects are shown to play an important role in the structural behavior and to contribute to an increase of the load-bearing capacity of the damaged structure. A computational parametric study is also reported in order to assess how the physical parameters aect the overall structural behavior and to identify the main physical parameters aecting the studied problems. The third and fourth structures are vestorey planar frames, each realistically designed in accordance with the minimum requirements proposed by the reinforced concrete design/building codes of Europe and Brazil. Nonlinear dynamic analysis is performed, including elasto-viscoplastic eects. The load combinations considered for progressive collapse analysis follow the prescriptions of the Department of Defense of the United States. The work veri- es if the minimum requirements of the considered codes are sucient for enforcing structural safety and robustness, and also points out the major dierences in terms of progressive collapse potential of the corresponding designed structures.

Palavras-chave:

Reinforced concrete structures; Corrotational formulation; Progressive collapse; Nonlinear dynamic analysis

Áreas de Concentração:

- Doutorado: Construção Metálica

Orientadores:

- Ricardo Azoubel da Mota Silveira

Banca Examinadora:

Prof. Ricardo Azoubel da Mota Silveira, Presidente (UFOP)
Prof. Francisco Célio de Araújo (UFOP)
Prof. Alexandre da Silva Galvão (UFSJ)
Prof. João Batista Marques de Sousa Jr. (UFC)
Prof. Walnório Graça Ferreira (UFES)

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