Nonlinear Analysis of Reinforced Concrete Vierendeel Trusses

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.

This paper considers the practical application of nonlinear models in the analysis of reinforced concrete structures. The results of some analyses performed using the reinforced concrete model of the general purpose finite element code Ansys are presented and discussed. The differences observed in the response of the same reinforced concrete beam as some variations are made in a material model that is always basically the same are emphasyzed. The consequences of small changes in modelling are discussed and it is shown that satisfactory results may be obtained from relatively simple and limited models.

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.

The non-linear behavior of reinforced concrete (RC) beams till the ultimate failure is a complicated phenomenon due to the involvement of heterogenic material properties and cracking behavior of concrete. Behavior prediction of reinforced concrete elements till failure is usually carried out using experimental testing, and the observations are recorded only at critical locations due to restriction in cost of testing equipment and accessories. In order to avoid the destructive testing, reduction of the cost of materials and manpower, the behavior prediction of RC beams is generally carried out using numerical methods. This paper presents study on non-linear flexural behavior of reinforced concrete beams. Non-linear finite element analysis of reinforced concrete beams under flexural loading is presented in this paper. Finite element modelling of reinforced concrete beams is carried out using discrete reinforcement modelling technique. The capability of the model to capture the critical crack regions, loads and deflections for various loadings in reinforced concrete beam has been illustrated. Comparison is made between the experimental results and finite element analyses with respect to initial crack formation and the ultimate load capacity of beams. The results obtained in the present study show close agreement with those in the available literature.

This paper considers the practical application of nonlinear models in the analysis of reinforced concrete structures. The results of some analyses performed using the reinforced concrete model of the general purpose finite element code Ansys are presented and discussed. The differences observed in the response of the same reinforced concrete beam as some variations are made in a material model that is always basically the same are emphasyzed. The consequences of small changes in modelling are discussed and it is shown that satisfactory results may be obtained from relatively simple and limited models.

Journal of Structural Engineering, 2014

Engineering Structures, 2012

In this paper, a finite element (FE) model for nonlinear analysis of reinforced concrete (RC) beams, considering shear deformation, is developed. The model is based on the Timoshenko Beam Theory and utilizes 3-noded bar elements with a total of 7 degrees of freedom. The Fiber Model is adopted, with the element section discretized into overlaid concrete and longitudinal reinforcement layers. Transverse reinforcement, when present, is considered to be smeared and embedded in the concrete layers. The Modified Compression Field Theory with some modifications is utilized for the material constitutive models, and a tension-stiffening model developed by the authors is included. The FE model was implemented into a computer program named ANALEST, developed by the authors, which allows for material and geometrical nonlinear analysis of RC beams and frames. The proposed model is validated via comparison with experimental results from tests on simply supported and continuous RC beams. Comparisons with numerical results from a Bernoulli-beam model are also included, and a few recommendations regarding the use of different FE models are given at the end.

2022

The nonlinear behavior of reinforced concrete beams is complex due to their heterogenic properties and crack formations. Thus, a more accurate estimation through experimental testing and nonlinear finite element modeling is necessary to understand better such behavior. Experimental testing of a reinforced concrete beam subjected to monotonic loading was conducted in laboratory. The test specimen along with seven specimens from various literature were then modeled and analyzed using VecTor2 software to investigate the capability of the software in predicting the load-displacement curves and crack patterns of the specimens. The analysis results show that the finite element model used in VecTor2 software is able to predict well the load-displacement curves and crack patterns of the specimens failing in flexure and shear mechanisms.

IJMER

This study presents theoretical investigation that reinforced concrete and composite construction might be suitably combined to give a new structural material : composite reinforced concrete. To study theoretically the composite beam, non-linear three-dimensional finite elements have been used to analyze the tested beam. The 8-node brick elements in (ANSYS) are used to represent the concrete, the steel bars are modelled as discrete axial members connected with concrete elements at shared nodes assuming perfect bond between the concrete and the steel. The results obtained by finite element solution showed good agreement with experimental results. The main objective of the present investigation is to carry out a nonlinear analysis of reinforced concrete beams resting on elastic foundation. Material nonlinearities due to cracking of concrete, plastic flow, crushing of concrete and yielding of reinforcement are considered. Foundation representation is assumed linear using Winkler model. The reinforced concrete beam is modelled by using three dimensional finite elements with steel bars as smeared layers. The examples have been chosen in order to demonstrate the applicability of the modified computer program (Dynamic Analysis of Reinforced Concrete Beams on Elastic Foundations DARCEF ) by comparing the predicted behaviour with that from other experimental and analytical observations. The program modified in the present research work is capable of simulating the behaviour of reinforced concrete beams resting of Winkler foundation and subjected to different types of loading. The program solutions obtained for different reinforced concrete beams resting on elastic foundations are in good agreement with the available results. Maximum percentage difference in deflection is 15 %

Engineering Structures, 2008

A constitutive model for reinforced concrete elements that takes into account the tensile capacity of the intact concrete between cracks, effect known as tension-stiffening, is proposed in this paper. In the model, the tensile stress-strain curve of concrete displays an exponential decay in the post-cracking range, defined by a parameter that depends on the reinforcement ratio and on the steel-to-concrete modular ratio. This parameter was derived taking as a basis the CEB tension-stiffening model. The model was implemented into a computational program that allows for nonlinear finite element analysis of reinforced concrete beams. The numerical results obtained by the program compared extremely well with several experimental results from simply supported beams tested under 4-point bending that displayed a dominant flexural behavior. Extension of the model to members subjected to combined flexural and shear is also presented.