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Magdi Mohareb - One of the best experts on this subject based on the ideXlab platform.
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effect of beam deck connection flexibility on lateral torsional Buckling strength of wooden twin beams
Engineering Structures, 2020Co-Authors: Ghasan Doudak, Magdi MoharebAbstract:Abstract Two finite element solutions are developed for the lateral torsional Buckling analysis of timber beam-deck assemblies consisting of two beams braced by decking through fasteners. In contrast to past solutions, both solutions capture the rotational flexibility provided by the connections between the deck boards and the beams. The first solution is intended for systems with partial lateral restraint provided by the deck boards allowing lateral sway while the second solution is intended for systems that are restrained from lateral movement at the deck level. An experimental program is conducted to quantify the rotational stiffness of beam-deck connections for different types of fasteners and the results are input into the finite element formulations to evaluate the corresponding Buckling capacities for beam-deck systems. The results indicate that the Buckling capacity of beam-deck systems can be significantly increased with commonly used fasteners while high-capacity fasteners can achieve Buckling capacities nearly identical to those where rigid rotational connections are assumed.
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distortional lateral torsional Buckling analysis of beams with overhangs
Journal of Structural Engineering-asce, 2019Co-Authors: Payam Pezeshky, Arash Sahraei, Magdi MoharebAbstract:AbstractThe present study investigated the effect of web distortion on the lateral torsional Buckling strength of Gerber systems. Toward this goal, a number of modifications were introduced into tw...
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Sway Model for the Lateral Torsional Buckling Analysis of Wooden Twin-beam-deck Systems
Structures, 2019Co-Authors: Magdi Mohareb, Ghasan DoudakAbstract:Abstract The present study develops a finite element model for the lateral torsional Buckling analysis of wooden twin beams braced by deck boards subjected to gravity or wind uplift loading. The restraining action of the deck boards is modelled as continuous partial lateral and twist restraints provided at the top of both beams that capture the interaction between both beams. A parametric study is then conducted to examine the effects of beam and deck spans, load type, load height, lateral restraint height and stiffness and number of beam spans on the overall Buckling capacity. The results indicate that the restraining effects of deck boards significantly improve the lateral torsional Buckling capacity of twin-beam-deck assemblies.
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distortional lateral torsional Buckling of beam columns including pre Buckling deformation effects
Computers & Structures, 2018Co-Authors: Payam Pezeshky, Magdi MoharebAbstract:Abstract The present study develops a unified distortional lateral torsional Buckling finite element formulation for the elastic analysis of beam-columns with wide flange doubly symmetric cross-sections. The solution captures several non-conventional features including the softening effect due to web distortion, the stiffening effect induced by pre-Buckling deformations, the pre-Buckling nonlinear interaction between strong-axis moments and axial forces, the contribution of pre-Buckling shear deformation effects, the destabilizing effects due to loads being offset from the shear centre, and the presence of transverse stiffeners on web distortion. In the present theory, it is possible to evoke/suppress any combination of features and thus isolate the individual contribution of each effect or quantify the combined contributions of multiple effects. The effects of beam span-to-depth, flange width-to-thickness, web height-to-thickness, and flange width-to-web height ratios on the critical moments are investigated. Comparisons with conventional lateral torsional Buckling solutions that omit distortional and pre-Buckling effects quantify the influence of distortional and/or pre-Buckling deformation effects. The theory is also used to investigate the influence of P-delta effects of beam-columns subjected to transverse and axial forces on their lateral torsional Buckling. The solution is adopted to quantify the beneficial effects of transverse stiffeners in controlling/suppressing web distortion in beams.
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effect of eccentric lateral bracing stiffness on lateral torsional Buckling resistance of wooden beams
International Journal of Structural Stability and Dynamics, 2018Co-Authors: Magdi Mohareb, Ghasan DoudakAbstract:An energy-based solution is developed for the lateral torsional Buckling (LTB) analysis of wooden beams with flexible mid-span lateral bracing offset from section mid-height and subjected to uniformly distributed or mid-span point load. The study shows that such beams are prone to two potential Buckling modes; symmetric or anti-symmetric. The symmetric mode is shown to govern the capacity of the beam for low bracing stiffness while the anti-symmetric mode governs the capacity when the bracing stiffness exceeds a threshold value. Using the present formulation, the threshold bracing stiffness required to suppress the symmetric mode and maximize the critical moments is directly obtained by solving a special eigenvalue problem in the unknown bracing stiffness. The technique thus eliminates the need for trial and error in standard solutions. A parametric study is conducted to investigate the effect of bracing height, load height, and bracing stiffness on the critical moments. A large database of runs is genera...
Jan Belis - One of the best experts on this subject based on the ideXlab platform.
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lateral torsional Buckling resistance of castellated beams
Journal of Structural Engineering-asce, 2017Co-Authors: Delphine Sonck, Jan BelisAbstract:AbstractThe existing design expressions for the Lateral-Torsional Buckling behavior of castellated beams conflict. Furthermore, they do not take into account the detrimental effect of the residual stress modification attributable to the fabrication process, which was only recently demonstrated by the authors. This makes these design rules possibly unsafe. In this paper, the Lateral-Torsional Buckling behavior of doubly symmetric castellated beams loaded by a constant bending moment is investigated numerically. The numerical model, including the modified residual stresses, was validated by comparing its results with experimental results. A preliminary design approach is proposed based on the current European guidelines for the calculation of the Lateral-Torsional Buckling resistance of I-section beams. According to the proposed approach, the Lateral-Torsional Buckling resistance of castellated beams can be determined using the cross-sectional properties calculated at the center of the web opening. The modi...
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mechanical behavior and resistance of structural glass beams in lateral torsional Buckling ltb with adhesive joints
Advanced engineering materials and modeling, 2016Co-Authors: Chiara Bedon, Jan BelisAbstract:Glass is largely used in practice as an innovative structural material, in the form of beams or plate elements able to carry loads. Compared to traditional construction materials, the major influencing parameter in the design of structural glass elements – in addition to their high architectural and aesthetic impact – is given by the well-known brittle behavior and limited tensile resistance of glass. In this chapter, careful attention is given to the Lateral-Torsional Buckling (LTB) response of glass beams laterally restrained by continuous adhesive joints, as in the case of glass facades or roofs. Closed-form solutions and Finite Element (FE) numerical approaches are recalled for the estimation of their Euler’s critical Buckling moment under various loading conditions. Nonlinear Buckling analyses are then critically discussed, by taking into account a multitude of mechanical and geometrical aspects. Design recommendations for laterally restrained glass beams in LTB are finally presented.
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lateral torsional Buckling resistance of cellular beams
Journal of Constructional Steel Research, 2015Co-Authors: Delphine Sonck, Jan BelisAbstract:Abstract The evenly spaced circular web openings in I-section cellular beams have an advantageous effect on the material use if these beams are loaded in strong-axis bending. However, not all aspects of the behaviour of such beams have been studied adequately, such as the lateral–torsional Buckling failure. For the latter failure mode, the existing design approaches conflict. Furthermore, the detrimental effect of the modification of the residual stresses by the production process, as recently demonstrated by the authors in previous work, was never taken into account. In this paper, the lateral–torsional Buckling behaviour of cellular beams is investigated using a numerical model that was validated based on experimental results. In this model, the effect of the modified residual stress pattern was aptly taken into account. Using the results of the parametric study, a preliminary design approach was proposed. This approach is based on the currently existing European guidelines for the calculation of the lateral–torsional Buckling resistance of I-section beams, but with a modified calculation of the cross-sectional properties and a modified Buckling curve selection.
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assessment of existing analytical models for the lateral torsional Buckling analysis of pvb and sg laminated glass beams via viscoelastic simulations and experiments
Engineering Structures, 2014Co-Authors: Chiara Bedon, Jan Belis, Andreas LuibleAbstract:Due to the large increase of structural glass applications, the lateral torsional Buckling behavior of glass beams actually represents a topic of great interest for researchers. Although several analytical models and design approaches exist in literature, various aspects complicate the realistic prediction of their typical out-of-plane response, especially if composed of two (or more) laminated glass sheets. Based on viscoelastic numerical results and predictions of a large experimental campaign of lateral torsional Buckling tests performed on PVB and SG beams, the paper investigates the accuracy of existing analytical models in the prediction of the elastic critical load and load-lateral displacement path of these elements.
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experimental and analytical assessment of lateral torsional Buckling of laminated glass beams
Engineering Structures, 2013Co-Authors: Jan Belis, Chiara Bedon, Christian Louter, Claudio Amadio, Rudy Van ImpeAbstract:Due to their increasing use in contemporary architecture, the lateral torsional Buckling performance of laminated structural glass beams represents a topic of great interest for researchers. Although several analytical models and design approaches have been recently proposed, various aspects complicate the realistic prediction of this phenomenon. Based on experimental results of a large campaign of lateral torsional Buckling tests (55 laminated beams), the paper investigates analytically the effects of various mechanical (e.g. the stiffness of interlayer) and geometrical properties (e.g. initial twist, production tolerances) on the typical lateral torsional Buckling response of laminated glass beams.
Mario M Attard - One of the best experts on this subject based on the ideXlab platform.
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lateral torsional Buckling analysis of thin walled beams including shear and pre Buckling deformation effects
International Journal of Mechanical Sciences, 2011Co-Authors: Emre R Erkmen, Mario M AttardAbstract:Abstract In this paper, lateral–torsional Buckling behavior of open-section thin-walled beams is investigated based on a geometrically nonlinear formulation, which considers the effects of shear deformations. A finite element numerical solution along with an incremental-iterative solution procedure is adopted to trace the pre-Buckling as well as the post-Buckling equilibrium paths. Formulation is applicable to a general type of open-section and load position effects are also included. Numerical results are validated through comparisons with experimental results and those based on other formulations presented in the literature. Comparisons have also been made between the results based on fully nonlinear analysis and linearized Buckling analysis in order to illustrate the effects of pre-Buckling deformations as well as the shear deformations on the Buckling load predictions. Examples illustrate the influence of beam slenderness and moment gradient on the effects of pre-Buckling deformations in predicting bucking loads.
Ghasan Doudak - One of the best experts on this subject based on the ideXlab platform.
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effect of beam deck connection flexibility on lateral torsional Buckling strength of wooden twin beams
Engineering Structures, 2020Co-Authors: Ghasan Doudak, Magdi MoharebAbstract:Abstract Two finite element solutions are developed for the lateral torsional Buckling analysis of timber beam-deck assemblies consisting of two beams braced by decking through fasteners. In contrast to past solutions, both solutions capture the rotational flexibility provided by the connections between the deck boards and the beams. The first solution is intended for systems with partial lateral restraint provided by the deck boards allowing lateral sway while the second solution is intended for systems that are restrained from lateral movement at the deck level. An experimental program is conducted to quantify the rotational stiffness of beam-deck connections for different types of fasteners and the results are input into the finite element formulations to evaluate the corresponding Buckling capacities for beam-deck systems. The results indicate that the Buckling capacity of beam-deck systems can be significantly increased with commonly used fasteners while high-capacity fasteners can achieve Buckling capacities nearly identical to those where rigid rotational connections are assumed.
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Sway Model for the Lateral Torsional Buckling Analysis of Wooden Twin-beam-deck Systems
Structures, 2019Co-Authors: Magdi Mohareb, Ghasan DoudakAbstract:Abstract The present study develops a finite element model for the lateral torsional Buckling analysis of wooden twin beams braced by deck boards subjected to gravity or wind uplift loading. The restraining action of the deck boards is modelled as continuous partial lateral and twist restraints provided at the top of both beams that capture the interaction between both beams. A parametric study is then conducted to examine the effects of beam and deck spans, load type, load height, lateral restraint height and stiffness and number of beam spans on the overall Buckling capacity. The results indicate that the restraining effects of deck boards significantly improve the lateral torsional Buckling capacity of twin-beam-deck assemblies.
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effect of eccentric lateral bracing stiffness on lateral torsional Buckling resistance of wooden beams
International Journal of Structural Stability and Dynamics, 2018Co-Authors: Magdi Mohareb, Ghasan DoudakAbstract:An energy-based solution is developed for the lateral torsional Buckling (LTB) analysis of wooden beams with flexible mid-span lateral bracing offset from section mid-height and subjected to uniformly distributed or mid-span point load. The study shows that such beams are prone to two potential Buckling modes; symmetric or anti-symmetric. The symmetric mode is shown to govern the capacity of the beam for low bracing stiffness while the anti-symmetric mode governs the capacity when the bracing stiffness exceeds a threshold value. Using the present formulation, the threshold bracing stiffness required to suppress the symmetric mode and maximize the critical moments is directly obtained by solving a special eigenvalue problem in the unknown bracing stiffness. The technique thus eliminates the need for trial and error in standard solutions. A parametric study is conducted to investigate the effect of bracing height, load height, and bracing stiffness on the critical moments. A large database of runs is genera...
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lateral torsional Buckling of wooden beams with midspan lateral bracing offset from section midheight
Journal of Engineering Mechanics-asce, 2017Co-Authors: Ye Hu, Magdi Mohareb, Ghasan DoudakAbstract:AbstractAn energy-based solution is developed for the lateral torsional Buckling analysis of wooden beams with a midspan lateral brace subjected to uniformly distributed loads or midspan point load...
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nonsway model for lateral torsional Buckling of wooden beams under wind uplift
Journal of Engineering Mechanics-asce, 2016Co-Authors: Magdi Mohareb, Ghasan DoudakAbstract:AbstractSimply supported wooden beams nailed to deck boards subjected to wind uplift forces are subjected to compressive stresses at their bottom fibers. Because the restraining action provided by decking is at the top fibers, it is unclear to what extent such restraints are effective in controlling lateral torsional Buckling as a possible mode of failure under wind uplift. Present design standards do not have provisions for such cases. Thus, the present study aims to quantify the effect of restraints provided by the deck boards on the lateral torsional Buckling capacity of twin-beam-deck systems under wind uplift. Toward this goal, a series of analytical and numerical models were formulated. All models capture the continuous rigid lateral restraint and partial twisting restraint provided by the deck boards. The effects of load type and load position were investigated. The bending stiffness of deck boards was observed to have a significant influence on the lateral torsional Buckling capacity of twin-beam-...
Payam Pezeshky - One of the best experts on this subject based on the ideXlab platform.
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distortional lateral torsional Buckling analysis of beams with overhangs
Journal of Structural Engineering-asce, 2019Co-Authors: Payam Pezeshky, Arash Sahraei, Magdi MoharebAbstract:AbstractThe present study investigated the effect of web distortion on the lateral torsional Buckling strength of Gerber systems. Toward this goal, a number of modifications were introduced into tw...
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distortional lateral torsional Buckling of beam columns including pre Buckling deformation effects
Computers & Structures, 2018Co-Authors: Payam Pezeshky, Magdi MoharebAbstract:Abstract The present study develops a unified distortional lateral torsional Buckling finite element formulation for the elastic analysis of beam-columns with wide flange doubly symmetric cross-sections. The solution captures several non-conventional features including the softening effect due to web distortion, the stiffening effect induced by pre-Buckling deformations, the pre-Buckling nonlinear interaction between strong-axis moments and axial forces, the contribution of pre-Buckling shear deformation effects, the destabilizing effects due to loads being offset from the shear centre, and the presence of transverse stiffeners on web distortion. In the present theory, it is possible to evoke/suppress any combination of features and thus isolate the individual contribution of each effect or quantify the combined contributions of multiple effects. The effects of beam span-to-depth, flange width-to-thickness, web height-to-thickness, and flange width-to-web height ratios on the critical moments are investigated. Comparisons with conventional lateral torsional Buckling solutions that omit distortional and pre-Buckling effects quantify the influence of distortional and/or pre-Buckling deformation effects. The theory is also used to investigate the influence of P-delta effects of beam-columns subjected to transverse and axial forces on their lateral torsional Buckling. The solution is adopted to quantify the beneficial effects of transverse stiffeners in controlling/suppressing web distortion in beams.
