NONLINEAR JOINT ELEMENT FOR THE ANALYSIS OF REINFORCEMENT BARS USING FINITE ELEMENTS

NONLINEAR JOINT ELEMENT FOR THE ANALYSIS OF REINFORCEMENT BARS USING FINITE ELEMENTS

Durand, R.; Farias, M. M.

Full Article:

Reinforcement bars are commonly found in engineering works such as soil nailing, tunnel excavation with the NATM process and in the conventional and pre-stressed reinforced concrete structures. Three approaches are found in the literature for the finite element analy-sis of such inclusions: the discrete, the smeared and the embedded methods. Each method has its own advantages, however none of them can account for the behavior of the interface be-tween the reinforcement bar and the reinforced medium. The contact simulation is crucial in many cases since the critical failure zone could be the interface itself. This kind of simulation was achieved with the semi-embedded method, proposed by the authors, which combines the advantages of the discrete and embedded methods. In this case reinforcements are composed by real bar elements linked to solid elements by means of joint elements. Each joint element comprises a set of real nodes which are connected to the bar elements and another set of vir-tual nodes that are linked to particular positions within a trespassed solid element. Joint ele-ments can adopt a nonlinear constitutive model in order to simulate the behavior of an inter-face failure zone. This paper describes a new and simpler formulation for the semi-embedded method that renders the implementation straightforward. A pull-out test application example is performed showing excellent accuracy.

Reinforcement bars are commonly found in engineering works such as soil nailing, tunnel excavation with the NATM process and in the conventional and pre-stressed reinforced concrete structures. Three approaches are found in the literature for the finite element analy-sis of such inclusions: the discrete, the smeared and the embedded methods. Each method has its own advantages, however none of them can account for the behavior of the interface be-tween the reinforcement bar and the reinforced medium. The contact simulation is crucial in many cases since the critical failure zone could be the interface itself. This kind of simulation was achieved with the semi-embedded method, proposed by the authors, which combines the advantages of the discrete and embedded methods. In this case reinforcements are composed by real bar elements linked to solid elements by means of joint elements. Each joint element comprises a set of real nodes which are connected to the bar elements and another set of vir-tual nodes that are linked to particular positions within a trespassed solid element. Joint ele-ments can adopt a nonlinear constitutive model in order to simulate the behavior of an inter-face failure zone. This paper describes a new and simpler formulation for the semi-embedded method that renders the implementation straightforward. A pull-out test application example is performed showing excellent accuracy.

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DOI: 10.5151/meceng-wccm2012-19278

Referências bibliográficas

• [1] Andrade, H.A.C., “Numerical procedures for the analisys of drainage elements is soils”. MSc Dissertation, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil, 125 p, 2003.
• [2] Durand, R., “Embedded stiffness method in the tree-dimensional analysis of reinforce-ments via finite elements”. MSc Dissertation, University of Brasilia, Brasilia, Brazil, 95 p., 2003.
• [3] Durand, R., “Three-dimensional analysis of geotechnical structures subjected to rein-forcement and drainage”. PhD Thesis, University of Brasilia, Brasilia, Brazil, 153 p, 2008.
• [4] Durand, R., Farias, M.M., “A generalized method for the extrapolation of internal values to the nodal points of finite elements”. In: 2nd International Workshop in Computational Geotechnics, IWS-Fortaleza, 1, 21-28, 2004.
• [5] Elwi, A.E., Hrudey, T.M., “Finite element model for curved embedded reinforcements”. Engineering Mechanics, ASCE, 115(4), 740-754, 1989.
• [6] Farias, M. M., Durand, R., “Embedded stiffness approach to compute the optimum con-figuration of reinforcements”. In: NUMOG IX, International Symposium on Numerical Models in Geomechanics, 1, 549-555, 2004.
• [7] Farias, M.M., Naylor, D.J., “Safety analysis using finite elements”. Computers and Ge-otechnics, Elsevier Science, 22(2), 165-181, 1998.
• [8] Hartl, H., “Development of a continuum-mechanics-based tool for 3D finite element anal-ysis of reinforced concrete structures and application to problems of soil-structure interac-tion”, PhD Thesis, Graz University of Technology, Graz, Austria, 250 p, 2002.
• [9] Kwak, H.G., Filippou, F.C., “Finite element analysis of reinforced concrete structures under monotonic loads”. Report No. UCB/SEMM-90/14, Department of Civil Engineer-ing, University of California, Berkeley, USA, 120 p, 1990.
• [10] Nakai, T., “Finite element computations for active and passive earth pressure problems of retaining wall”. Soils and Foundations, 25(3), 98-11, 1985.

Como citar:

Durand, R.; Farias, M. M.; "NONLINEAR JOINT ELEMENT FOR THE ANALYSIS OF REINFORCEMENT BARS USING FINITE ELEMENTS", p-3253-3268. In: In Proceedings of the 10th World Congress on Computational Mechanics [= Blucher Mechanical Engineering Proceedings, v. 1, n. 1]. São Paulo: Blucher, 2014.
ISSN 23580828, DOI 10.5151/meceng-wccm2012-19278