Development of steel-concrete interface model for structural elements (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.
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...
Boundary element model for bond problems in reinforced concrete members
Computers & Structures, 1994
A numerical procedure for the analysis of the bond stress distribution along the steeLconcrete interface of reinforced concrete members is presented. Considering a reinforcing steel bar embedded in a surrounding cylinder of concrete, the analysis is based on a boundary element formulation in axisymmetric elasticity and on a local bond stress-slip nonlinear relationship which is able to model the contact interface behaviour observed by experimental tests. The results of practical application of the procedure to the case of uniaxial tension are in very good agreement with those presented by other authors using a finite element model and they are in sufficient agreement with those which for the particular scheme examined can be obtained by an analytical approach. The proposed model is advantageous with respect to a finite element model because it does not need special bond elements, allows a reduced number of unknowns and transfers the nonlinearity of the problem only to a number of equations equal to the number of nodal points at the contact interface.
Crack opening estimate in reinforced concrete walls using a steel–concrete bond model
Archives of Civil and Mechanical Engineering, 2016
This paper presents the application of a new steel-concrete bond model on a reinforced concrete shear wall, experimentally tested during the French National Project CEOS.FR. The proposed results include both global (evolution of the force as a function of the displacement for example) and local results (crack opening and spacing). A new post-processing method to compute these local properties even in a case of a complex crack pattern (oriented cracks for example) is proposed. It is based on the change in the sign of the bond slip between steel and concrete. The simulated results are in a good agreement with the experiment and validate the developments. Finally, the interest of including a specific steel-concrete bond model in the finite element simulation is highlighted, compared to classical "no-slip" relation.
Mechanical properties of constitutive parameters in steel–concrete interface
Engineering Structures, 2011
Mechanical properties of steel-concrete interface are evaluated on the basis of three existing experimental evidences. The properties include bond strength, unbounded and bonded friction angles, residual level of friction angle, mode I fracture energy, mode II bonded fracture energy and unbonded slip-friction energy under different level of normal stress, and shape parameters defining geometrical shape of failure envelope. For this purpose, a typical type of constitutive model of describing steel-concrete interface behavior is presented based on a hyperbolic threeparameter Mohr-Coulom failure criterion. The constitutive model depicts the strong dependency of interface behavior on bonding condition of interface, bonded or unbounded. Mechanical roles of interface parameters are discussed based on the presented interface model. Values of the interface parameters are determined through interpretation of existing experimental results, geometry of failure envelope and sensitivity analyses. These values are applied to push-out tests of concrete-infilled rectangular steel columns with three different cases of interface lengths.
Local bond stress-slip model for reinforced concrete joints and anchorages with moderate confinement
Canadian Journal of Civil Engineering, 2017
This paper presents a summary of an experimental investigation and the derivation of a bond-slip model for reinforcing steel embedded in moderately confined concrete under monotonic and cyclic loadings. Moderately confined concrete encompasses the domain between unconfined and well-confined concrete, the limits of which are defined in the paper. The proposed constitutive law adapts and extends the well-known Eligehausen-Filippou model for well-confined concrete to moderately confined concrete. It is described by an envelope curve and degradation rules. The former is obtained through a confinement index, defined in this study as a function of the amount of confining steel and concrete, distance between confining steel and the rebar, and concrete segregation effect. It is proposed to adopt the same degradation rules used for well-confined concrete. These rules are validated through statistical tests for moderately confined concrete. They are found to predict correctly the main feature...
Simulating bond failure in reinforced concrete by a plasticity model
Computers Structures, 2012
In this work, an axisymmetric plasticity model is used to simulate the concrete-steel interface behavior. A nonlocal correction is here introduced in order to capture the degradation of the bond due to splitting cracks. Damage of the interface is also modeled as a function of the rib spacing, allowing application of the model to different bar diameters. The model is able to capture the transition from splitting to pull-out failure and to yielding of bars with the same set of predefined interface parameters, showing the predictive character of the model. The development of macroscopic cracks is also correctly simulated.
International Journal of Concrete Structures and Materials, 2020
A nonlinear finite element model (FEM) is developed to assess the behaviour of a cracked concrete interface, reinforced with embedded steel bars and subjected to monotonic loading. A dowel action finite element modelling approach is conceived for that purpose. The bond between the steel bars and the surrounding concrete is also considered in the model and an interface finite element is included to simulate aggregate interlock. Then, the comparison of the model results with experimental values allowed the calibration of aggregate interlock constitutive relations for cracks in monolithic concrete restrained by embedded steel bars. New constitutive relations are also proposed for shear transfer by aggregate interlock in a concrete joint.
Nonlinear Analysis of Reinforced Concrete Beams Considering the Slip Between Steel and Concrete
In this work aspects of interaction between steel and concrete, for reinforced concrete structures, with particular interest in the mechanism of slip that occurs in the steel-concrete interface are presented. A nonlinear computational model which considers the bond-slip behavior between reinforcing steel and concrete for the nonlinear analysis of beams subjected to bending is developed. The finite element method is used to predict the behavior of reinforced concrete structures based on the properties of the concrete, the reinforcing steel, and the relationship of the steel-concrete interface. The concept about equivalent uniaxial stress-strain model proposed by [1] is used to describe the nonlinear behavior of reinforced concrete which incorporates tensile cracking at a limiting stress and the strain-softening phenomenon beyond the maximum compressive strength from an incremental load procedure with an iterative approach to obtain an equilibrium position of the structure for each increment. The bond is modeled with interface element (bond-zone element) connecting the steel and concrete elements. The interface element presented by [2] has its stiffness based on the stages of relationship between the local bond stress and the relative slip of the bar, for incremental load process. Several numerical examples comparing results of bending beams are presented.