Locking problems in the partial interaction analysis of multi-layered composite beams

Double skin composite (DSC) construction consists of a layer of a plain concrete, sandwiched between two layers of relatively thin steel plate, connected to the concrete by welded stud shear connectors. This construction acts in a similar way to doubly reinforced concrete elements but the flexibility of connection between the steel plates and concrete gives rise to interface slip and additional overall element deflection. This results in a strong and efficient structure with certain potential advantages over conventional forms of construction. This paper presents a theoretical analysis of the behavior of simply supported single span DSC beams, assuming both full and partial interaction. The partial interaction analysis takes into account the flexibility of connection on both tension and compression faces. The partial interaction analysis is extended to cover the influence of frictional forces between the concrete and external steel plates, at the supports and load points. The theoretical solutions based on partial interaction theory, assuming realistic material and shear connector properties and incorporating the influence of interface frictional forces between the concrete and external steel plates, at the supports and load points, are compared with the results of tests on DSC beams. It is concluded that the proposed method shows good correlation with real behavior and may be reliably used for the analysis of simply supported single span DSC beams.

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

Mathematics and Mechanics of Solids ◽

10.1177/1081286516653799 ◽

2016 ◽

Vol 22 (10) ◽

pp. 2011-2039 ◽

Cited By ~ 2

Author(s):

Gerard Taig ◽

Gianluca Ranzi

Keyword(s):

Structural Response ◽

Beam Theory ◽

Element Model ◽

Composite Beams ◽

Cross Sectional ◽

Shear Connections ◽

Dynamic Analyses ◽

Partial Interaction ◽

Deformation Modes ◽

Generalised Beam Theory

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.

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