Generalised Beam Theory for composite beams with longitudinal and transverse partial interaction

2016 ◽  
Vol 22 (10) ◽  
pp. 2011-2039 ◽  
Author(s):  
Gerard Taig ◽  
Gianluca Ranzi

This paper presents a Generalised Beam Theory formulation to study the partial interaction behaviour of two-layered prismatic steel–concrete composite beams. The novelty of the proposed approach is in its capacity to handle the deformability of the shear connections at the interface between the slab and steel beam in both the longitudinal and transverse directions in the evaluation of the deformation modes. This method falls within a category of cross-sectional analyses available in the literature for which a suitable set of deformation modes, including conventional, extension and shear, is determined from dynamic analyses of discrete planar frame models representing the cross-section. In this context, the shear connections are modelled using shear deformable spring elements. As a result, the in-plane partial shear interaction behaviour is accounted for in the planar dynamic analysis during the evaluation of the conventional and extension modes, while the longitudinal partial interaction behaviour associated with the shear modes is included in the out-of-plane dynamic analyses. In the case of the conventional modes, the longitudinal slip is accounted for in the post-processing stage where the warping displacements are determined. A numerical example of a composite box girder beam is presented and its structural response investigated for different levels of shear connection stiffness in both the longitudinal and transverse directions. The accuracy of the numerical results is validated against those obtained with a shell finite element model implemented in ABAQUS/Standard software.

2014 ◽  
Vol 553 ◽  
pp. 600-605
Author(s):  
Gerard Taig ◽  
Gianluca Ranzi

A Generalised Beam Theory (GBT) formulation is presented to analyse the structural behaviour of shear deformable thin-walled members with partially stiffened cross-sections located at arbitrary locations along their length. The deformation modes used in the formulation are taken as the dynamic eigenmodes of a planar frame representing the unstiffened cross-section. Constraint equations are derived and implemented in the GBT member analysis to model the influence of rigid stiffeners on the member response. The accuracy of the approach is validated against a shell finite element model developed in Abaqus. A numerical example describing the linear elastic behaviour of partially stiffened thin-walled member is provided to outline the usability and flexibility of the proposed method.


2016 ◽  
Vol 20 (10) ◽  
pp. 1451-1465 ◽  
Author(s):  
Shou-Chao Jiang ◽  
Gianluca Ranzi ◽  
Ling-Zhu Chen ◽  
Guo-Qiang Li

This article presents an extensive experimental and numerical study aimed at the evaluation of the thermo-structural response of composite beams with composite slabs. Two full-scale fire tests were carried out on simply supported composite steel-concrete beams with steel sheeting perpendicular and parallel to the steel joist, respectively. Both specimens were observed to fail by developing large displacements. Concrete crushing at the mid-span, debonding of the profiled sheeting and spalling of the fire protection were observed during both tests. A three-dimensional finite element model was developed in ABAQUS, and its accuracy was validated against the experimental measurements collected as part of this study. The model was then used to perform a parametric study to determine the influence of the degree of shear connection, load ratio and design fire rate on the structural response of composite beams at elevated temperatures. These results, together with experimental data available in the literature, were used to evaluate the ability of European guidelines to predict the critical temperature of composite beams. It was shown that predictions from Eurocode 4 were safe and provided conservative estimates for most cases.


1999 ◽  
Vol 26 (6) ◽  
pp. 852-868 ◽  
Author(s):  
Mohammad Z Kabir ◽  
Archibald N Sherbourne

The paper presents a theoretical study on the static structural response of thin-walled composite open-section beams. Based on a Vlasov-type linear hypothesis, a beam theory is formulated in terms of in-plane elastic properties to analyze composite I and channel section pultruded beams which includes the transverse shear deformation of the beam cross section. The importance of the shear influence on the total vertical deflection is reported. Symmetric lay-up composite beams result in a bending-twisting structural coupling. The optimal fibre orientation for minimizing vertical displacements and twist angle is also investigated.Key words: pultruded, shear strain, composite beams, twist.


2017 ◽  
Vol 11 (1) ◽  
pp. 384-395 ◽  
Author(s):  
Alessandro Zona ◽  
Graziano Leoni ◽  
Andrea Dall’Asta

Background: In this work the behaviour of continuous steel-concrete composite beams with different shear connection distributions obtained from two design methods, i.e. Eurocode 4 and a proposed alternative approach, is analysed. Objective: For this purpose a finite element model specifically developed for the nonlinear analysis of steel-concrete composite beams is adopted. This finite element model includes material nonlinearity of slab concrete, reinforcement steel, beam steel as well as slab-beam nonlinear partial interaction due to the deformable shear connection. The inclusion of the partial interaction in the composite beam model provides information on the slab-beam interface slip and shear force and enables to model the failure of the shear connectors. Results and Conclusion: In this way it is possible to analyse and quantify the effect of shear connector distributions on the global and local response of continuous steel-concrete composite beams, both under service load levels and at collapse. Particular attention is focused on the ductility requirements on the shear connectors when varying the connection design approach and distribution.


2019 ◽  
Author(s):  
Miguel Abambres ◽  
Dinar Camotim ◽  
Nuno Silvestre

After providing a brief overview of a recently developed and validated elastoplastic post-buckling Generalised Beam Theory (GBT) formulation, the paper presents and discusses illustrative numerical results concerning three tubular members exhibiting bi-linear and non-linear material behaviours. The GBT results consist of equilibrium paths, modal participation diagrams, stress contours, displacement profiles and collapse mechanisms, most of which are compared with values obtained from Abaqus shell finite element analyses. The GBT modal nature makes it possible to (i) acquire in-depth knowledge about the member behavioural mechanics at any given equilibrium state (elastic or elastic-plastic), as well as (ii) evidence the GBT computational efficiency (d.o.f. reduction of over 75%), partly due to the exclusion from the analyses of all deformation modes playing no role in a given member response.


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