1,721,033 research outputs found
Service and ultimate analyses of composite beams with partial interaction in combined bending and shear
No full textThis paper compares three different beam models for the linear viscoelastic (service state) analysis and nonlinear (ultimate state) analysis of composite members with partial interaction. These models are derived by coupling with a deformable shear connection two Euler-Bernoulli beams (only flexural deformability and flexural failure mode), an Euler-Bernoulli beam to a Timoshenko beam (addition of shear deformability and shear failure mode for one component only), and two Timoshenko beams (addition of shear deformability and shear failure mode for both components). Results of service state analyses involving 200 realistic simply supported and three-span composite beams as well as results of nonlinear analyses involving experimentally tested simply supported and continuous beams are illustrated in order to study the effects of shear in the steel and slab components at various load levels. Results show that the three models show small differences when composite beams are dominated by the bending behaviour. Conversely, differences are significant for beams in which the interaction between bending and shear plays a substantial role
Nonlinear analysis of composite beams with partial interaction including the combined effects of bending and shear
No full textThree different beam models for the nonlinear analysis of composite members with partial interaction are compared in this study. The considered models are obtained by coupling with a deformable shear connection two Euler-Bernoulli beams (only flexural deformability and flexural failure mode of each beam component), an Euler-Bernoulli beam to a Timoshenko beam (addition of the shear deformability and shear failure mode for one component only), two Timoshenko beams (addition of the shear deformability and shear failure mode for both components). Composite beams for which experimental results are available in the literature are used as benchmark problems to validate the numerical results. Aspects of the composite behaviour evaluated include (i) the effects of the shear deformability of the steel and slab components at various load levels; (ii) the differences in computed collapse loads obtained with the three beam models
A steel-concrete composite beam model with partial interaction including the shear deformability of the steel component
No full textThis paper presents an analytical model for the analysis of steel–concrete composite beams with partial shear interaction including the shear deformability of the steel component. This model is obtained by coupling an Euler–Bernoulli beam for the reinforced concrete slab to a Timoshenko beam for the steel beam. The composite action is provided by a continuous shear connection which enables relative longitudinal displacements to occur between the two components. The balance conditions are derived using the principle of virtual work and the weak form of the problem is presented. The steel of the beam and the steel of the slab reinforcement are modelled by using linear elastic laws, while the timedependent
behaviour of the slab concrete is included by using a general linear viscous–elastic integral-type constitutive law. The numerical solution is obtained by means of the finite element method implementing a time-stepping procedure. The derived displacement-based finite elements are
tested and their performance is discussed. Extensive numerical simulations are carried out on approximately 200 realistic simply supported and three-span composite beams to evaluate the effects of the shear deformability of the steel member on the overall structural response. The numerical results obtained with the proposed model are compared to those of the composite beam model with partial shear interaction that does not include the shear deformability of the steel beam to determine under which conditions shear deformations of the steel component need to be considered in the analysis of composite systems and to evaluate how these are affected by the shear connection stiffness and by the redistributions due to the time-dependent behaviour of the concrete slab
Analysis of the shear lag effect in cable stayed bridges by means of deck finite elements
No full textABSTRACT
This paper presents the derivation of a finite element formulation for the analysis of composite decks accounting for partial interaction theory and shear-lag effects. The particularity of the proposed element, referred to as the deck finite element, relies on its ability to capture the structural response of cable stayed bridges, while preserving the ease of use of a typical line element. For these particular bridges, stress concentrations are induced in the slab by the application of concentrated forces due to the anchorage of stays. The ease of use of the proposed deck finite element is outlined considering a case study for which the calculated results have been compared against those obtained using a more refined model implemented using shell elements in a commercial finite element software
General method of analysis for composite beams with longitudinal and transverse partial interaction
No full textThis paper presents an analytical formulation for the analysis of two-layered composite beams with longitudinal and vertical partial interaction. The particularity of this model is its ability to incorporate an interface connection deforming both longitudinally, i.e., along the beam length, and vertically, i.e., transverse to the connection interface, which is modelled by means of a uniformly distributed spring. The novel formulation is based on the principle of virtual work expressed in terms of the displacement field consisting of the vertical and axial displacements of the two layers; for completeness, the proposed model is presented in both its weak and strong forms. The partial interaction problem is then solved by means of the finite element method. A parametric study is presented to investigate the effects of different combinations of longitudinal and transverse connection rigidities on the overall structural response. For the purpose of these simulations, a bi-linear constitutive model has been specified for the transverse interface connection to reflect the more realistic case in which two different responses are observed in the transverse interaction, one in which one layer is bearing against the other one, one when the two layers are separating. An iterative procedure has been proposed to obtain the convergence to the final solution. (c) 2006 Elsevier Ltd. All rights reserved
Analytical design equations for the calculation of the effective width for the analysis of composite steel-concrete bridge decks
No full textThis paper proposes new analytical expressions for the determination of effective widths for the analysis of twin-girder
steel-concrete composite bridge decks. The main advantage of the proposed approach relies on its ability to evaluate the
normal longitudinal stress distribution on the slab by means of a cross sectional analysis carried out using the internal
actions calculated by means of a global analysis specifying the real width of the slab along the whole bridge length. The
proposed expressions are shown to be able to handle different loading conditions which include constant uniformly
distributed loads, envelopes of transverse actions due to traffic loads, support settlements and concrete shrinkage.
Comparisons with the methodology recommended by design guidelines are carried to highlight the ease of use and
effectiveness of the proposed method considering realistic continuous twin-girder composite bridge decks
Analysis of the shear-lag effect in steel-concrete cable stayed bridges by means of deck finite elements
No full textThis paper presents the derivation of a finite element formulation for the analysis of composite decks accounting for partial interaction theory and shear-lag effects. The particularity of the proposed element, referred to as the deck finite element, relies on its ability to capture the structural response of cable stayed bridges, while preserving the ease of use of a typical line element. For these particular bridges, stress concentrations are induced in the slab by the application of concentrated forces due to the anchorage of stays. The ease of use of the proposed deck finite element is outlined considering a case study for which the calculated results have been compared against those obtained using a more refined model implemented using shell elements in a commercial finite element software
Partial interaction behaviour of composite steel-concrete members at elevated temperatures accounting for geometric nonlinearities
No full textThis paper presents a numerical model for the analysis of composite steel-concrete beams at elevated temperatures accounting for both longitudinal and transverse interaction within the framework of nonlinear finite deformation theory. A reduced formulation, useful for solving structural problems, is then derived on the basis of the theory of small strain and moderate rotations. The numerical solution proposed relies on the use of the finite element method. As the scope of this study is restricted to moderately elevated temperatures, elastic material properties are assumed for all materials while still accounting for their degradation with temperature. A bilinear constitutive model is adopted for the transverse interface connection to reflect the more realistic case in which an extremely high connection stiffness exists for the bearing condition of the concrete slab against the steel joist, and a relatively weaker stiffness is manifested when the joist and slab are separating. A brief numerical example is then presented for a beam configuration subjected to a thermal distribution typical of real fire scenarios and pinned at its ends
The effects of the shear deformability of composite beams on their long-term and ultimate behaviour
No full textThis paper presents a comparative study between the performance of three different beam models to describe the long-term and ultimate behaviour of composite members with partial interaction. In particular, these models are derived coupling by means of a flexible shear connection two Euler-Bernoulli beams (commonly referred to as Newmark beam model), a Euler-Bernoulli beam and a Timoshenko beam, and two Timoshenko beams, respectively. The numerical solutions are obtained by means of the finite element method. The effects of including the shear deformability of the steel joist is discussed at service conditions based on an extensive parametric study carried out on approximately 100 realistic three-span composite beams. The differences in using the three beam models in predicting the ultimate composite behaviour is then discussed using experimental results available in the literature as benchmark problems
Partial interaction analyses of composite steel-concrete girders subjected to combined bending and shear
No full textThree different beam models for the linear viscoelastic analysis and nonlinear analysis of steel-concrete composite girders including partial interaction are compared, i.e., models derived by coupling with a deformable shear connection two Euler-Bernoulli beams (only flexural deformability and flexural failure mode), an Euler-Bernoulli beam to a Timoshenko beam (addition of shear deformability and shear failure mode for one component only), and two Timoshenko beams (addition of shear deformability and shear failure mode for both components). Results of linear analyses involving 200 simply supported and three-span compo-site girders as well as results of nonlinear analyses involving experimentally tested simply supported and con-tinuous beams are illustrated to evaluate the effects of shear in the steel and slab components at various load levels. Results show that differences between the three models are significant in many cases
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