Time dependent finite element analysis of steel-concrete composite beams considering partial interaction

Lat. Am. j. solids struct.

2018

In this work, a finite element-based approach is presented to study the effective width variation in non-pre-stressed steel-concrete beams under the serviceability stage, including time dependent effects such as concrete creep, shrinkage and cracking. For this purpose, the viscoelasticity theory in conjunction with a nonlinear cracking monitoring algorithm is used to trace the nonlinear viscoelastic response of the structure along time. The present numerical model is fully three-dimensional and permits the inclusion of partial interaction at the slab-beam interface. A comprehensive study is carried out on the long-term response of a composite girder bridge previously studied by other researches. Then, previous results are revised and extended herein. Potential shortcomings of some standard codes related to the effective width evaluation are also investigated. It is demonstrated that the slab effective width varies sharply along the beam axis in the short-term, while it approaches to the actual slab width in the long-term. For the studied example, the common assumption of using only the middle layer of the reinforced concrete (RC) slab for the effective width calculation is revised with a through-thickness integration procedure. The influence of some creep and shrinkage models as well as the ultimate tensile concrete strain on the effective width response is also assessed. Finally, a simple formula is proposed to evaluate the short-term slab effective width for the studied example.

Section: Reinforced Concrete Slabmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Finite element study of effective width in steel-concrete composite beams under long-term service loads

Reginato

Tamayo

Lat. Am. j. solids struct.

2018

“…Internal unbonded tendons may slip in relation to the surrounded concrete along its entire length, whereas external tendons only slip at deviator devices located along the longitudinal direction of the steel beam. The model is based on the enhacement of a previous model called VIMIS, developed by the authors, and which have served as FE tool for other numerical studies , Dias et al 2015, and Reginato et al 2018. The strategy for including internal and external prestressing and some aspects of the numerical modeling of composite beams are then commented in the following sections.…”

Section: Introductionmentioning

confidence: 99%

“…The model is able to capture the entire ultimate load response of continuous steel-concrete composite beams and their time-dependent behavior due to concrete creep and shrinkage for serviceability analyses. For this purpose, the short-term elastoplastic model with the long-term algorithm based on the theory of viscoelasticity are coupled (Dias et al 2015). Concrete creep is taken into consideration using Kelvin's rheological model through a step by step time incremental procedure.…”

Section: Introductionmentioning

confidence: 99%

Some Aspects of Numerical Modeling of Steel-Concrete Composite Beams with Prestressed Tendons

Tamayo

Franco

Lat. Am. j. solids struct.

et al. 2019

Aspects about the numerical modeling of three-dimensional prestressed steel-concrete composite beams by using the finite element (FE) method are highlighted and commented in this work. Emphasis is given to the numerical treatment of bonded and unbonded tendons. The proposed modeling technique uses curved beam and catenary elements for simulating internal and external tendons, respectively. Other issues such as the constitutive model for shear connectors, steel beam and concrete are also discussed. Several numerical examples with experimental and numerical results are presented. It is encountered that a faster numerical convergence is achieved when the tendon stiffness is included in the overall stiffness of the structure, even when the unbonded internal situation is addressed. Moreover, omitting slipping at the deviator device may lead to inaccurate results in the evaluation of tendon forces for external prestressing. Favourable agreement is encountered for all studied examples.

“…This paper is based on the works of Dias [7], Dias et al [8], Quevedo [9] and Schmitz [10], who used the long-term concrete formulation proposed by the Comité Euro-International du Béton (CEB-FIP MC90) [3] adapted to the Solidification theory of the Bazant and Prasannan ( [1], [2]) for their studies involving composite beams, tunnels and bridges, respectively. The creep formulation of the CEB-FIP MC90 has the advantage of fitting perfectly with the Bazant and Prasannan theory.…”

Section: Introductionmentioning

confidence: 99%

Customization of a software of finite elements to analysis of concrete structures: long-term effects

Quevedo

Schmitz

Rev. IBRACON Estrut. Mater.

et al. 2018

Concrete is a material that presents time-delayed effects associated with creep and shrinkage phenomena. The numerical modeling of the creep is not trivial because it depends on the age of the concrete at the time of loading, which makes necessary to store the history of loads to apply the principle of superposition. However, a problem formulated in finite elements has many points of integration, making this storage impossible. The Theory of Solidification, together with incremental algorithm developed by Bazant e Prasannan ([1], [2]), solves this problem. Therefore, this paper presents the adaptation of this algorithm to a finite element commercial software (ANSYS) considering the creep, according to the CEB-FIP Model Code 1990 [3]. The results demonstrate that the deformations provided by this adaptation are in accordance with the analytical solution given by the CEB-FIP MC90, including cases where the loads are applied at different ages of the concrete.