Modeling Material Failure in Concrete Structures under Cyclic Actions (original) (raw)
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Modeling Material Failure in Concrete Structures
A constitutive model devised for the analysis of concrete structures, and suitable for generic two- or three-dimensional applications, is presented and validated. For plain concrete a tension-compression distinguishing stress split is performed, and two scalar damage variables account for the degradation induced by the tensile and compressive stress components. As outcomes the model reproduces the stiffness recovery upon load reversal, and it captures the strength enhancement under multiaxial compression. Besides, the simple formulation as well as the extremely reduced number of parameters involved in the concrete model makes it quite suitable for the analysis of real structures, and constitutes a useful design tool. As regards to the nonlinear performance of the steel reinforcement, the explicit Giuffrè–Menegotto–Pinto model is adopted. Efficiency of the global model is illustrated via two seismic applications: one concerning an arch dam, and the other a six-floor reinforced concrete wall. The latter application is presented for validation purposes.
Cyclic constitutive model for concrete
Engineering structures, 2008
A constitutive model for concrete subjected to cyclic loadings in both compression and tension is presented. The proposed model is intended to provide improvements on modelling the cyclic behaviour of concrete structures in the context of computational programs based on a smeared crack approach. Particular emphasis has been paid to the description of the strength and stiffness degradation produced by the load cycling in both tension and compression, the shape of unloading and reloading curves and the transition between opening and closing of cracks. Two independent damage parameters in compression and in tension have been introduced to model the concrete degradation due to increasing loads. In the case of cyclic compressive loading, the model has been derived from experimental results obtained by other authors by considering the dependency of the cyclic variables with the damage level attained by the concrete. In the case of cyclic tension a simple model is adopted based on experimental observations. The main novelty of the proposed constitutive model lays in the fact that all the required input data can be obtained through the conventional monotonic compression and tension tests.
An analytical model, which can simulate the biaxial description of the nonlinear behavior of reinforced concrete structures, is introduced. The behavior of concrete is assumed orthotropic inside the ultimate failure surface and a compressive softening law of concrete is presented. The behavior of cracked concrete is simulated using the smeared crack model, which the tension stiffening effect based on a cracking criterion derived from the fracture mechanics principles is considered. A computer program is developed for analyzing the over and under-reinforced concrete beams. Several parameters such as the non-linearity proprieties, the cut off and tension stiffening models and shear retention factor are studied. The correlation between analytical and experimental results shows the validity of the proposed models and the significance of various effects. The global responses are evaluated to verify simultaneously the reliability of the proposed model and the performance of the numerical program.
Nonlinear analysis of reinforced concrete structures using a new constitutive model
Revue européenne des éléments finis, 2004
An analytical model, which can simulate the biaxial description of the nonlinear behavior of reinforced concrete structures, is introduced. The behavior of concrete is assumed orthotropic inside the ultimate failure surface and a compressive softening law of concrete is presented. The behavior of cracked concrete is simulated using the smeared crack model, which the tension stiffening effect based on a cracking criterion derived from the fracture mechanics principles is considered. A computer program is developed for analyzing the over and under-reinforced concrete beams. Several parameters such as the non-linearity proprieties, the cut off and tension stiffening models and shear retention factor are studied. The correlation between analytical and experimental results shows the validity of the proposed models and the significance of various effects. The global responses are evaluated to verify simultaneously the reliability of the proposed model and the performance of the numerical program.
International Journal of Structural and Civil Engineering Research, 2020
Reliable design of reinforced concrete (RC) structures against earthquake has received considerable attention for many decades. It is vital that RC members exhibit sufficient strength and ductility under combinations of gravity loads and cyclic lateral excitations caused by earthquakes. To that end, this study presents an Enhanced Concrete Damage Plasticity Model (ECDPM) for predicting the cyclic behavior of plain concrete under multiaxial loading conditions, which combines the theories of classic plasticity and continuum damage mechanics. This model employs two damage variables for describing the influences of tensile and compressive damages on overall behavior. The capability of the model to predict the cyclic response of plain concrete is evaluated using experimental data from a uniaxial tension test, as well as uniaxial, biaxial and triaxial compression tests. Very good agreement is generally observed between the numerical predictions and test data. Various shortcomings of the model are also identified to aid future development efforts. Index Terms-damage-plasticity model, plain concrete, cyclic loading, multiaxial loading conditions 273
A complete method to predict the behavior of reinforced concrete structures with beams and columns controlled by flexure is proposed. The concrete is modelled with a damage mechanics approach. The parameters of the model are adjusted on material tests and various procedures that account for confinement and cyclic response. Steel is modelled with a simple cyclic model. A simplified finite element program allows the prediction of the global and the local behavior from the constitutive laws of the material. This program uses multilayer beam elements. Localization of damage for softening structures is taken into consideration by a meshing procedure. The methodology is used to predict the behavior of three different kinds of structures subjected to three different types of loading. Predictions are in very good agreement with experimental results.
Behavior modeling and damage quantification of confined concrete under cyclic loading
Structural Engineering and Mechanics
Sets of nonlinear formulations together with an energy-based damage index (DI) are proposed to model the behavior and quantify the damage of the confined and unconfined concretes under monotonic and cyclic loading. The proposed formulations and DI can be employed in numerical simulations to determine the stresses and the damages to the fibers or the layers within the sections of reinforced concrete (RC) components. To verify the proposed formulations, an adaptive finite element computer program was generated to simulate the RC structures subjected to monotonic and cyclic loading. By comparing the simulated and the experimental test results, on both the full-scale structural members and concrete cylindrical samples, the proposed uniaxial behavior modeling formulations for confined and unconfined concretes under monotonic and cyclic loading, based on an iterative process, were accordingly adjusted, and then validated. The proposed formulations have strong mathematical structures and can readily be adapted to achieve a higher degree of precision by improving the relevant coefficients based on more precise tests. To apply the proposed DI, the stress-strain data of concrete elements is required. It can easily be calculated by using the proposed nonlinear stress-strain models for confined and unconfined concretes in this paper.
New Tension-Compression Damage Model for Complex Analysis of Concrete Structures
Journal of Engineering Mechanics, 2016
A new damage model, based on continuum damage mechanics and simulating the opening, closing and reopening of cracks in concrete using only one surface of discontinuity, is proposed in this article. The model complies with the thermodynamics principles of non-reversible, isothermal and adiabatic processes. Two scalar internal variables have been defined: a tensile damage variable d + and a compressive damage variable d − ; the threshold of damage is controlled by only one surface of discontinuity and a new parameter that controls the damage variable which should be activated. This new parameter represents the ratio of tensile stress to compressive stress in the damaged material. The continuity of response under complex loads, which is one of the aims of this work, is ensured. An adequate response under different types of loads leads to the conclusion that the proposed model provides a powerful tool to numerically analyze reinforced concrete structures. Validation and illustrative examples are included in the article.
Plasticity-Damage Model for Concrete under Cyclic Multiaxial Loading
Journal of Engineering Mechanics-asce, 1993
A model that combines plasticity and damage mechanics is developed to assess both multiaxial monotonic and cyclic behavior of concrete. The model adopts a bounding surface concept and combines plastic deformation with the deformation due to damage. Plastic strain components are calculated by using the plastic modulus that is a function of the distance from the current stress point to the bounding surface along the deviatoric stress direction S o. Similarly, damage growth rate is obtained by the hardening modulus, which is a function of the distance just defined. The hardening behavior of concrete is assumed herein to be controlled by both damage and plasticity, while the strain-softening regime is controlled by damage processes only. The simultaneous use of the plasticity surface and the damage surface, leads to a constitutive model that accounts for the essential features of concrete such as pressure sensitivity, shear compaction-dilatancy, stiffness degradation, and softening behavior.