Crack opening estimate in reinforced concrete walls using a steel–concrete bond model (original) (raw)
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A new bond slip model for reinforced concrete structures
Engineering Computations, 2015
Purpose – The purpose of this paper is to present a new bond slip model for reinforced concrete structures. It consists in an interface element (3D) which represents the interface between concrete (modeled in 3D) and steel, modeled using 1D truss elements. Design/methodology/approach – The formulation of the interface element is presented and verified through a comparison with an analytical solution on an academic case. Finally, the model is compared with experimental results on a reinforced concrete tie. Findings – Contrary to the classical perfect or “no-slip” relation which supposes the same displacement between steel and concrete, the proposed model is able to reproduce both global (force-displacement curve) and local (crack openings) results. Originality/value – The proposed approach, applicable to large-scale computations, represents a valuable alternative to the no-slip relation hypothesis to correctly capture the crack properties of reinforced concrete structures.
Purpose – The purpose of this paper is to present a new bond slip model for reinforced concrete structures. It consists in an interface element (3D) which represents the interface between concrete (modeled in 3D) and steel, modeled using 1D truss elements. Design/methodology/approach – The formulation of the interface element is presented and verified through a comparison with an analytical solution on an academic case. Finally, the model is compared with experimental results on a reinforced concrete tie. Findings – Contrary to the classical perfect or “no-slip” relation which supposes the same displacement between steel and concrete, the proposed model is able to reproduce both global (force-displacement curve) and local (crack openings) results. Originality/value – The proposed approach, applicable to large-scale computations, represents a valuable alternative to the no-slip relation hypothesis to correctly capture the crack properties of reinforced concrete structures.
SHEAR WALL MOCK UP SUBJECTED TO MONOTONIC LOADING WITH CONCRETE STEEL BOND MODEL
This paper presents a numerical simulation of a shear-wall mock-up subjected to monotonic loading with a new steel-concrete bond model. First, global responses (forcedisplacement curves) are compared to the experimental results and show a good agreement between simulation and experiment. In order to compare the local responses such as crack orientation, crack spacing and crack opening, a new post-processing method is presented. It is based on the definition of the crack path from the displacement field or the change in the sign of the bond slip. The crack opening is then obtained using the displacement in the normal direction of the crack. The method is applied on the shear wall and the results are compared to the experimental data obtained with digital image correlation. A good agreement is once again obtained.
Numerical Simulation of the Behavior of Cracked Reinforced Concrete Members
Materials Sciences and Applications, 2014
Refined non-linear static or dynamic analyses of reinforced concrete structures require the knowledge of the actual force-displacement or bending moment-rotation curves of each structural member, which depend on the crack widths and on the crack pattern, and after all on the slip between concrete and reinforcing steel. For this reason the definition of improved local models taking into account all these local aspects is a fundamental prerequisite for advanced assessment of r.c. structures. A numerical procedure which allows to predict the relative displacement between steel reinforcement and the surrounding concrete in a reinforced concrete element, once assigned the stress in the naked steel bar and the bond-slip law is discussed. The method provides as final outcomes the sequence of crack openings and the individual crack widths, regardless of the particular bond-slip correlation adopted. The proposed procedure is implemented referring to two relevant experimental case studies, demonstrating that it is able to predict satisfactorily actual strain fields and slips along the investigated reinforced concrete elements.
Role of bond on crack width in reinforced concrete members in tension
This paper aims to investigate the effectiveness of 1D numerical models in representing the global and local behaviour of reinforced concrete tension ties. These simplified approaches, mainly based on bond, neglect the contribution of stress diffusion in concrete blocks between cracks, which has been recognised as one of the most influencing parameters, especially for the evaluation of crack width. To investigate the influence of this assumption, a simplified 1D model has been here developed and verified through comparisons with reliable experimental data, as well as with results provided by a more refined 2D Finite Element model. The main results have shown that simplified models appear to be suitable to investigate local behaviour of the analysed elements and can be adopted to perform extensive parametric studies investigating the main variables influencing crack width. Full text available at: www.gruppofrattura.it/ocs/index.php/ICMFF/ICMFF10/paper/download/12138/11526
Experimental and finite element analysis of bond-slip in reinforced concrete
Revista IBRACON de Estruturas e Materiais, 2015
The modeling of reinforced concrete structures has taken advantage of the increasing progress on Computational Mechanics, in such way that complex phenomena, such as cracking and crushing, creep, reinforcement yielding, steel-concrete bond loss, can be modeled in a reasonable realistic way, using the proper set of numerical and computational resources. Among several options, the ones based on the Finite Element Method (FEM) allow complex analysis simulations of reinforced concrete structures, including the interaction of different nonlinear effects. This paper deals with the nonlinear finite element analysis of the bond-slip between reinforcing steel and concrete, taking into account an experimental study previously performed. The FEM analysis presented uses a combination of resources where the material behavior of concrete is described by the Microplane Constitutive Model, and an embedded reinforcement model is used to represent steel inside the concrete and take into account the e...
Development of steel-concrete interface model for structural elements
2018
In numerical applications of reinforced concrete structures, the steel-concrete interface behavior has a vital importance when the cracking properties are investigated. A finite element approach for the steel-concrete interface to be used in large-scale simulations was proposed by (Torre-Casanova, 2013) and (Mang, 2016). It enables to calculate the slip between the steel and concrete in the tangential direction of the interface element representation. The aim is here to improve the initial bond-slip model to be more efficient and more representative. The document is divided into three parts: 1) The existing bond-slip model is evaluated. The bond-slip model is then improved by considering transversal and irreversible bond behaviors under alternative loads. The new bond-slip model is validated with several numerical applications. 2) Confinement effect is implemented in the bond-slip model to capture the effect of external lateral pressure. According to the performed numerical applicat...
CRACKING IN SHEAR WALLS: EXPERIMENTAL RESULTS AND ANALYTICAL PREDICTIONS
This paper is a contribution to the analysis of cracking (crack width, spacing and orientation) in reinforced concrete shear walls under seismic loading. First, the experimental campaign of the French national project CEOS.fr and several test results obtained by different measurement techniques applied on the test specimens are presented. These results are compared to those obtained by the application of design codes formulas. For assessing the crack width, it is necessary to perform a structural analysis; the reinforced concrete shear wall specimen is modelled by the Finite Element (FE) software Code_Aster using three different approaches: (i) linear elastic behaviour, (ii) GLRC_DM global homogenized nonlinear constitutive law for reinforced concrete and (iii) ENDO_ISOT_BETON nonlinear concrete law for a semi-global approach (multilayer element). The results of the FE analysis are then used to compute the crack width. The structural modelling is highlighted as a major parameter for a good assessment. Procedures to calculate crack width based on the fib Model Code 2010 approach are proposed and a good agreement to the experimental results is obtained. Finally, the effects of the cyclic loading at Ultimate Limit State, as the values of residual crack width after an earthquake, are presented and discussed.