Papers by khalil BELAKHDAR
Steel and Composite Structures, 2018
This research presents an investigation on the thermal buckling resistance of FGM plates having p... more This research presents an investigation on the thermal buckling resistance of FGM plates having parabolic-concave thickness variation exposed to uniform and gradient temperature change. An analytical formulation is derived and the governing differential equation of thermal stability is solved numerically using finite difference method. A specific function of thickness variation is introduced where it controls the parabolic variation intensity of the thickness without changing the original material volume. The results indicated that the loss ratio in buckling resistance is the same for any gradient temperature profile. Influencing geometrical and material parameters on the loss ratio in the thermal resistance buckling are investigated which may help in design guidelines of such complex structures.
Jordan Journal of Civil Engineering, 2008
This paper presents an implementation of a rational three-dimensional nonlinear finite element mo... more This paper presents an implementation of a rational three-dimensional nonlinear finite element model for evaluating the behavior of reinforced concrete slabs strengthened with shear bolts under transverse load. The concrete was idealized by using eight-nodded brick elements. While both flexural reinforcement and the shear bolts were modeled as truss elements, a perfected bond between brick elements and truss elements was assumed. The nonlinear behavior of concrete in compression is simulated by an elasto-plastic work-hardening model, and in tension a suitable post-cracking model based on tension stiffening and shear retention models are employed. The steel was simulated using an elastic-full plastic model. The validity of the theoretical formulations and the program used was verified through comparison with available experimental data, and the agreement has proven to be good. A parametric study has been also carried out to investigate the influence of the shear bolts’ diameter and n...
Jordan Journal of Civil Engineering, 2007
A nonlinear finite element code has been developed to suite the analysis of normal and high stren... more A nonlinear finite element code has been developed to suite the analysis of normal and high strength concrete slabs. The computer program was built up using two computer languages, where the program interface part was coded in Visual-Basic language, while the main part was coded using FORTRAN language. A software called NLFEAS (Non-Linear Finite Element Analysis of Slabs) was developed to predicate and study the three dimensional response of reinforced concrete slabs of different grades, variables and boundary conditions under monotonically increasing loads. Using symmetry, a segment representing one quarter of the slab was considered in the analysis which was modeled using 20-node isoparametric brick elements and a 27-integration rule (3*3*3). Proper numerical material models for cracked concrete were incorporated in the analysis. The efficiency and accuracy of the developed code was verified through comparison with available test data, which showed good agreement. The effects of s...
A numerical investigation on the buckling resistance of FGM plates having parabolic-concave thick... more A numerical investigation on the buckling resistance of FGM plates having parabolic-concave thickness variation exposed to in-plane loading is presented in this piece of research work. An analytical formulation is derived and the governing differential equation of stability is solved numerically using finite difference method. A specific function of thickness variation is introduced, where this function controls the parabolic variation intensity of the plate thickness without changing its original material volume. The results indicated that the loss ratio in the buckling resistance due to parabolic-concave thickness variation is highly dependent on the geometrical properties of the plate, while it is not affected by the material properties or by the distribution profile of the constituent materials. Influencing material and geometrical parameters on the degradation of the buckling resistance are investigated, which may help in design guidelines of such complex structures.
The urban expansion and the increase in population led the urbanization to use the spaces "c... more The urban expansion and the increase in population led the urbanization to use the spaces "called at risks". The integration and the treatment of ground's movements constitute an important characteristic of the equilibrium established by nature. In the Saida town (Algeria), many projects built on grounds with problems showed signs of degradations such as cracks in structures. These degradations led to the total destruction of the building. The principal causes of these disasters are: the nature of the expansive nature of soils and landslides, disaster phenomenon not considered in the first study of these constructions. The damage also touched road embankments, highways and foundations. In order to solve these problems, it was necessary to propose a geotechnical and risks map for the ZHUN EAST (ESSALAM city, Saida), city which includes several yard of the soil with problems, using the geographical information systems (GIS/MapInfo). These tools enable us to express the p...
The urban expansion and the increase in population led the urbanization to use the spaces called ... more The urban expansion and the increase in population led the urbanization to use the spaces called “at risk”.The integration and the treatment of ground’s movements constitute an important characteristic of the equilibrium established by nature. In the Saida town (Algeria), many projects built on grounds with problems showed signs of degradations such as cracks in structures. These degradations led to the total destruction of the buildings. The principal causes of these disasters are: the expansive nature of soils and landslides, and the disaster phenomenon not considered in the first study of these constructions. The damage also touched road embankments, highways and foundations. In order to solve these problems, it was necessary to propose a geotechnical and risk map for the ZHUN EAST (ESSALAM city, Saida), a city which includes several yards of the soil with problems, using the Geographical Information Systems (GIS/MapInfo). These tools enable us to express the perception of space ...
Three dimensional nonlinear finite element analysis of high strength reinforced concrete slabs
In this paper, a new application of a four variable refined plate theory to analyze the nonlinear... more In this paper, a new application of a four variable refined plate theory to analyze the nonlinear bending of functionally graded plates exposed to thermo-mechanical loadings, is presented. This recent theory is based on the assumption that the transverse displacements consist of bending and shear components in which the bending components do not contribute toward shear forces, and similarly, the shear components do not contribute toward bending moments. The derived transverse shear strains has a quadratic variation across the thickness that satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. The material properties are assumed to vary continuously through the thickness of the plate according to a power-law distribution of the volume fraction of the constituents. The solutions are achieved by minimizing the total potential energy. The non-linear strain–displacement relations in the von Karman sense are us...
Geomechanics and Engineering
In this work, an efficient and simple quasi-3D hyperbolic shear deformation theory is developed f... more In this work, an efficient and simple quasi-3D hyperbolic shear deformation theory is developed for bending and vibration analyses of functionally graded (FG) plates resting on two-parameter elastic foundation. The significant feature of this theory is that, in addition to including the thickness stretching effect, it deals with only 5 unknowns as the first order shear deformation theory (FSDT). The foundation is described by the Pasternak (twoparameter) model. The material properties of the plate are assumed to vary continuously in the thickness direction by a simple power law distribution in terms of the volume fractions of the constituents. Equations of motion for thick FG plates are obtained within the Hamilton's principle. Analytical solutions for the bending and free vibration analysis are obtained for simply supported plates. The numerical results are given in detail and compared with the existing works such as 3-dimensional solutions and those predicted by other plate theories. It can be concluded that the present theory is not only accurate but also simple in predicting the bending and free vibration responses of functionally graded plates resting on elastic foundation.
Steel and Composite Structures, 2015
A numerical solution using finite difference method to evaluate the thermal buckling of simply su... more A numerical solution using finite difference method to evaluate the thermal buckling of simply supported FGM plate with variable thickness is presented in this research. First, the governing differential equation of thermal stability under uniform temperature through the plate thickness is derived. Then, the governing equation has been solved using finite difference method. After validating the presented numerical method with the analytical solution, the finite difference formulation has been extended in order to include variable thickness. The accuracy of the finite difference method for variable thickness plate has been also compared with the literature where a good agreement has been found. Furthermore, a parametric study has been conducted to analyze the effect of material and geometric parameters on the thermal buckling resistance of the FGM plates. It was found that the thickness variation affects isotropic plates a bit more than FGM plates.
Steel and Composite Structures, Apr 25, 2014
Jordan Journal of Civil Engineering, 2008
This paper presents an implementation of a rational three-dimensional nonlinear finite element mo... more This paper presents an implementation of a rational three-dimensional nonlinear finite element model for evaluating the behavior of reinforced concrete slabs strengthened with shear bolts under transverse load. The concrete was idealized by using eight-nodded brick elements. While both flexural reinforcement and the shear bolts were modeled as truss elements, a perfected bond between brick elements and truss elements was assumed. The nonlinear behavior of concrete in compression is simulated by an elasto-plastic work-hardening model, and in tension a suitable post-cracking model based on tension stiffening and shear retention models are employed. The steel was simulated using an elastic-full plastic model. The validity of the theoretical formulations and the program used was verified through comparison with available experimental data, and the agreement has proven to be good. A parametric study has been also carried out to investigate the influence of the shear bolts' diameter and number of bolts' rows around the column-slab connection, on the ductility and ultimate load capacity of slabs.
Composite Structures, 2015
Abstract This paper presents an advanced finite element model using the general purpose FE softwa... more Abstract This paper presents an advanced finite element model using the general purpose FE software Ansys to simulate the flexural behaviour of initially damaged concrete beams repaired with FRP plates. The model is capable to simulate the full history stages; where the beam is initially loaded to introduce damage, then, after bonding the FRP plates, the beam is reloaded up to failure. The finite element model has been validated using experimental data in the literature and used to study the effect of concrete-FRP models, interfacial shear stress distribution, crack pattern, and failure mechanism. In addition, the effect of plate thickness and the gained load capacity in terms of damage degree have been also investigated. The predicted results indicated that the load capacity of all repaired beams is higher than that of the control beam for any damage degree. Moreover, when repairing highly damaged beams, the most likely expected mode of failure is plate debonding for any FRP plate thickness.
IOSR Journal of Mechanical and Civil Engineering, 2013
Structural reliability analysis aims to compute the probability of failure by considering system ... more Structural reliability analysis aims to compute the probability of failure by considering system uncertainties. However, this approach may require very time-consuming computation and becomes impracticable for complex structures especially when complex computer analysis and simulation codes are involved such as finite element method. Approximation methods are widely used to build simplified approximations, or metamodels providing a surrogate model of the original codes. The most popular surrogate model is the response surface methodology, which typically employs second order polynomial approximation using least-squares regression techniques. Several authors have been used response surface methods in reliability analysis. However, another approximation method based on kriging approach has successfully applied in the field of deterministic optimization. Few studies have treated the use of kriging approximation in reliability analysis and reliability-based design optimization. In this paper, the kriging approximation is used an alternative to the traditional response surface method, to approximate the performance function of the reliability analysis. The main objective of this work is to develop an efficient global approximation while controlling the computational cost and accurate prediction. A pilot point method is proposed to the kriging approximation in order to increase the prior predictivity of the approximation, which the pilot points are good candidates for numerical simulation. In other words, the predictive quality of the initial kriging approximation is improved by adding adaptive information called "pilot points" in areas where the kriging variance is maximum. This methodology allows for an efficient modeling of highly non-linear responses, while the number of simulations is reduced compared to Latin Hypercubes approach. Numerical examples show the efficiency and the interest of the proposed method.
The urban expansion and the increase in population led the urbanization to use the spaces called ... more The urban expansion and the increase in population led the urbanization to use the spaces called "at risk".The integration and the treatment of ground's movements constitute an important characteristic of the equilibrium established by nature. In the Saïda town (Algeria), many projects built on grounds with problems showed signs of degradations such as cracks in structures. These degradations led to the total destruction of the buildings. The principal causes of these disasters are: the expansive nature of soils and landslides, and the disaster phenomenon not considered in the first study of these constructions. The damage also touched road embankments, highways and foundations. In order to solve these problems, it was necessary to propose a geotechnical and risk map for the ZHUN EAST (ESSALAM city, Saïda), a city which includes several yards of the soil with problems, using the Geographical Information Systems (GIS/MapInfo). These tools enable us to express the perception of space and data processing, and consequently the cartography is carried out in an optimal way. These geotechnical and risk maps have a great part of importance in all levels of a study as information, working paper, alert, and especially is a tool for the decision-making aid, by expressing tendencies and orientations. They enabled us to give a field representing the active and potential movements with a hierarchy of risks to guide the developer and the engineer.
... and SM El Hassar Laboratoire des Matériaux et Hydrologie, Université de Sidi Bel Abbes, BP 89... more ... and SM El Hassar Laboratoire des Matériaux et Hydrologie, Université de Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000 Sidi Bel Abbes, Algérie Received ... 8. AM Malek, H. Saadatmanesh and MR Ehsani, Prediction of failure load of R/C beams strengthened with FRP plate ...
The urban expansion and the increase in population led the urbanization to use the spaces "called... more The urban expansion and the increase in population led the urbanization to use the spaces "called at risks". The integration and the treatment of ground's movements constitute an important characteristic of the equilibrium established by nature. In the Saïda town (Algeria), many projects built on grounds with problems showed signs of degradations such as cracks in structures. These degradations led to the total destruction of the building. The principal causes of these disasters are: the nature of the expansive nature of soils and landslides, disaster phenomenon not considered in the first study of these constructions. The damage also touched road embankments, highways and foundations. In order to solve these problems, it was necessary to propose a geotechnical and risks map for the ZHUN EAST (ESSALAM city, Saïda), city which includes several yard of the soil with problems, using the geographical information systems (GIS/MapInfo). These tools enable us to express the perception of space and data processing, and consequently the cartography is carried out in an optimal way. These geotechnical and risks maps have a great part of importance in all levels of a study as information, working paper, alert, and especially is a tool for the decision-making aid, by expressing tendencies and orientations. They enabled us to give a field representing the active and potential movements with a hierarchy of risks to guide the developer and the engineer.
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Papers by khalil BELAKHDAR