New solution for damaged porous RC cantilever beams strengthening by composite plate

Abderezak, Rabahi,Daouadji, Tahar Hassaine,Rabia, Benferhat Techno-Press 2021 Advances in materials research Vol.10 No.3

This research presents a careful theoretical investigation on interfacial stresses in damaged porous RC cantilever beams strengthened with externally bonded composite plate (several types of composites have been used). The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened cantilever beam, i.e., the damaged porous concrete cantilever beam, the perfect and/or imperfect composite plate and the adhesive layer. The analytical predictions are compared with other existing solutions and which shows a very good agreement of the results. It is shown that both the normal and shear stresses at the interface are influenced by the material and geometry parameters of the composite beam. In the end, I think this research is very useful for understanding the mechanical behavior of the interface and the design of the hybrid structures.

A Low-Computational High-Performance Model Predictive Control of Single Phase Battery Assisted Quasi Z-Source PV Inverters

Abderezak Lashab,Dezso Sera,Josep M. Guerrero 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Impedance network inverters are a good alternative for voltage-source and current-source inverters. The shootthrough solution and the boosting capability of such converters make them an excellent solution for photovoltaic (PV) application. Furthermore, energy storage integration in these inverters does not require any additional components in the converter; indeed, a battery can be directly connected in parallel with one of the capacitors of the Z- or quasi Z-network. However, for an optimal control of these converters, complex control and modulation strategies are required. Model Predictive Control (MPC) provides high control performance at the expense of the computational effort. In this paper, a low computational control method where both MPC and proportional resonant (PR) controller are combined, is proposed. This makes the proposed controller perform two iterations only instead of iterating for all the available switching states. As shown in the obtained results, the proposed controller conserves the high performance of the conventional MPC with 50% less computational burden.

Modeling and analysis of the imperfect FGM-damaged RC hybrid beams

Abderezak, Rabahi,Daouadji, Tahar Hassaine,Rabia, Benferhat Techno-Press 2021 Advances in computational design Vol.6 No.2

The use of externally bonded composite materials for strengthening reinforced concrete structures has received considerable attention in recent years. Since, concrete is a relatively fragile material and will fail when subject to the influence of many factors whose origins can be mechanical, physicochemical and accidental or related to the design and miscalculations. The bonding of FRP plate to reinforced concrete structure, appeared in the middle of the fourtwenties years, proves to be a promising and fully justified technique. In this paper, an analysis and modeling of the concentrations of interfacial stresses in a damaged reinforced concrete beam strengthening in bending by an imperfect FGM plate, was presented, based on a development of a mathematical formulation taking into account the theory of beams. The theoretical predictions are compared with other existing solutions. This research is helpful for the understanding on mechanical behaviour of the interface and design of the imperfect FGM - damaged RChybrid structures.

Mechanical behavior of RC cantilever beams strengthened with FRP laminate plate

Abderezak, Rabahi,Tahar, Hassaine Daouadji,Rabia, Benferhat,Tounsi, Abdelouahed Techno-Press 2021 Advances in computational design Vol.6 No.3

In this paper, an analytical interfacial stress analysis is presented for simply supported concrete cantilever beam bonded with a composite plate. The adherend shear deformations have been included in the present analyses by assuming a linear shear stress through the thickness of the adherends, one of the strong points of this model; this shear parameter has not been taken up by other researchers. Remarkable effect of shear deformations of adherends has been noted in the results. Indeed, the resulting interfacial stresses concentrations are considerably smaller than those obtained by other models which neglect adherent shear deformations. It is shown that both the normal and shear stresses at the interface are influenced by the material and geometry parameters of the composite beam. The theoretical predictions are compared with other existing solutions. This type of research is very useful for structural calculating engineers who are always looking to optimize strengthening design parameters and implement reliable debonding prevention measures.

Elastic analysis of interfacial stresses in prestressed PFGM-RC hybrid beams

Abderezak, Rabahi,Rabia, Benferhat,Daouadji, Tahar Hassaine,Abbes, Boussad,Belkacem, Adim,Abbes, Fazilay Techno-Press 2018 Advances in materials research Vol.7 No.2

In this paper, the problem of interfacial stresses in damaged reinforced concrete beams strengthened with bonded prestressed functionally graded material plate and subjected to a uniformly distributed load, arbitrarily positioned single point load, or two symmetric point loads is developed using linear elastic theory. The adopted model takes into account the adherend shear deformations by assuming a linear shear stress through the depth of the damaged RC beam. This solution is intended for application to beams made of all kinds of materials bonded with a thin FGM plate. The results show that there exists a high concentration of both shear and normal stress at the ends of the functionally graded material plate, which might result in premature failure of the strengthening scheme at these locations. Finally, numerical comparisons between the existing solutions and the present new solution enable a clear appreciation of the effects of various parameters of the beams on the distributions of the interfacial stresses.

Rehabilitation of RC structural elements: Application for continuous beams bonded by composite plate under a prestressing force

Abderezak, Rabahi,Rabia, Benferhat,Daouadji, Tahar Hassaine Techno-Press 2022 Advances in materials research Vol.11 No.2

This paper presents a closed-form higher-order analysis of interfacial shear stresses in RC continuous beams strengthened with bonded prestressed laminates. For retrofitting reinforced concrete continuous beams is to bond fiber reinforced prestressed composite plates to their tensile faces. An important failure mode of such plated beams is the debonding of the composite plates from the concrete due to high level of stress concentration in the adhesive at the ends of the composite plate. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. In the present theoretical analysis, the adherend shear deformations are taken into account by assuming a parabolic shear stress through the thickness of both the RC continuous beams strengthened with bonded prestressed laminates. The theoretical predictions are compared with other existing solutions. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as laminate stiffness and the thickness of the laminate where all were found to have a marked effect on the magnitude of maximum shear and normal stress in the composite member.

Analysis of interfacial stresses of the reinforced concrete foundation beams repairing with composite materials plate

Abderezak, Rabahi,Daouadji, Tahar Hassaine,Rabia, Benferhat Techno-Press 2020 Coupled systems mechanics Vol.9 No.5

This paper presents a careful theoretical investigation into interfacial stresses in reinforced concrete foundation beam repairing with composite plate. The essential issue in the analysis of reinforced structures with composite materials is to understand the individual behaviour of each material and its interaction with the remaining ones. The present model is based on equilibrium and deformations compatibility requirements in and all parts of the repaired RC foundation beam, i.e., the reinforced concrete foundation beam, the composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions, By comparisons between the existing solutions and the present new solution enable a clear appreciation of the effects of various parameters such as the geometric characteristics and mechanical properties of the components of the repaired beam, as well as the geotechnical stresses of the soil are considered. This research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-concrete hybrid structures.

Fiber reinforced polymer in civil engineering: Shear lag effect on damaged RC cantilever beams bonded by prestressed plate

Abderezak, Rabahi,Daouadji, Tahar Hassaine,Rabia, Benferhat Techno-Press 2021 Coupled systems mechanics Vol.10 No.4

This paper presents a careful theoretical investigation into interfacialstressesin damaged RC cantilever beamwith bonded prestressedFRPcomposites,taking into accountloadingmodel,shearlag effect and theprestressed compositesimpact.These composites areused,in particular,forrehabilitationofstructuresby stoppingthepropagation of the cracks. They improve rigidity and resistance, and prolong their lifespan. In this paper, an original model is presented to predict and to determine the stresses concentration attheFRPend,with the newtheory analysis approach. This research gives more precision related to the others studies which neglect the effect of prestressed composites coupled with the applied loads. A parametric study has been conducted to investigate the sensitivity of interface behaviorto parameterssuch aslaminate and adhesive stiffness, the thickness ofthe laminate and the fiber orientations where allwere found to have amarked effect on themagnitude ofmaximumshear and normalstressin the composite member. The numerical resolution was finalized by taking into account the physical and geometric properties of materialsthat may play an important role in reducing the stress values. Thisresearch is helpful for the understanding on mechanical behaviour ofthe interface and design ofthe FRP-damagedRChybrid structures.

Elastic analysis of interfacial stress concentrations in CFRP-RC hybrid beams: Effect of creep and shrinkage

Abderezak, Rabahi,Daouadji, Tahar Hassaine,Abbes, Boussad,Rabia, Benferhat,Belkacem, Adim,Abbes, Fazilay Techno-Press 2017 Advances in materials research Vol.6 No.3

A simple closed-form solution to calculate the interfacial shear and normal stresses of retrofitted concrete beam strengthened with thin composite plate under mechanical loads including the creep and shrinkage effect has been presented in this paper. In such plated beams, tensile forces develop in the bonded plate, and these have to be transferred to the original beam via interfacial shear and normal stresses. Consequently, debonding failure may occur at the plate ends due to a combination of high shear and normal interfacial stresses. These stresses between a beam and a soffit plate, within the linear elastic range, have been addressed by numerous analytical investigations. Surprisingly, none of these investigations has examined interfacial stresses while taking the creep and shrinkage effect into account. In the present theoretical analysis for the interfacial stresses between reinforced concrete beam and a thin composite plate bonded to its soffit, the influence of creep and shrinkage effect relative to the time of the casting, and the time of the loading of the beams is taken into account. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions.

Aluminum beam reinforced by externally bonded composite materials

Abderezak, Rabahi,Daouadji, Tahar Hassaine,Rabia, Benferhat Techno-Press 2021 Advances in materials research Vol.10 No.1

A recently popular method for retrofitting reinforced structure beams is to bond composite plates to their tensile faces. An important failure mode of such plated beams is the debonding of the composite plates from the base material of the beam due to high level of stress concentration in the adhesive at the ends of the composite plate. This paper, shows and presents in more detail a closed-form rigorous solution for interfacial stress in cantilever aluminum beams strengthened with bonded composite (sika wrap) plates and subjected to a uniformly distributed load. The results show that there exists a high concentration of both shear and normal stress at the ends of the laminate, which might result in premature failure of the strengthening scheme at these locations. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as laminate and adhesive stiffness, the thickness of the laminate; the effect on plate length of the strengthened cantilever beam region, the effect of adhesive (modules, thickness) and the effect of loading and geometry for the cantilever beam; where all were found to have a marked effect on the magnitude of maximum shear and normal stress in the composite member. The theoretical predictions are compared with other existing solutions. Finally, this research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-aluminum hybrid structures.