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Paper 154

Creep and Shrinkage Analysis of Curved Composite Beams Including the Effects of Partial Interaction

X. Liu1, R.E. Erkmen2 and M.A. Bradford1
1Centre for Infrastructure Engineering and Safety, Faculty of Engineering, The University of New South Wales, Sydney, Australia
2Centre for Built-Infrastructure Research, School of Civil and Environmental Engineering, University of Technology, Sydney, Australia

Keywords: composite beams, curvature, flexible connections, creep, shrinkage, viscoelasticity.

full paper (pdf) - reference

Curved composite beams comprised of concrete deck, structural steel girders and headed mechanical shear connectors between the deck and the girder have become a widespread form of construction in bridges and buildings in engineering structures. Despite this, comprehensive studies of curved composite beams appear to be very limited in the open literature, and with the evolution of rapid transport systems that rely on close deflection tolerances, studies addressing curved composite beams are much needed.

In composite beams, the flexibility of the shear connectors that join the deck and the girder causes partial shear interaction which may significantly influence the deformations of composite beams [1]. For curved composite beams however, partial interaction not only exists in the tangential direction but also in the radial direction since radial deflection and twist of the beam occurs even under vertical loading. A beam model that incorporates partial interaction in the tangential direction as well as in the radial direction in the elastic analysis of composite beams curved in plan is adopted herein [2].

On the other hand, in structural engineering design, satisfying serviceability limit states is a vital component for the design of steel and concrete composite beams [3]. In order to satisfy these serviceability requirements, an accurate assessment of the creep and shrinkage effects on the deflections is required. In this study time-dependent creep and shrinkage effects of the concrete deck including concrete age effects are considered by using the analytic age-adjusted effective modulus method (AEMM). The accuracy and efficiency of the proposed approach is shown by comparing its results with available experimental results reported in the literature and those based on a more sophisticated but computationally less efficient Abaqus shell finite element model.

It is demonstrated that the initial curvature of the beam has a significant influence on the time-dependent behaviour of composite beams under serviceability conditions.

It is also shown that the effects of partial interaction between the two composite components should be taken into consideration for an accurate time-dependent analysis, since the assumption of full interaction may misestimate the deformations. The slip effect due to warping is also closely examined in the current study

References

1
N.M. Newmark, C.P. Siess, I.M. Viest, "Tests and analysis of composite beams with incomplete interaction", Proc Soc Exper Stress Anal., 9(1),75-92, 1951.
2
R.E. Erkmen, M.A, Bradford, "Nonlinear elastic analysis of composite beams curved in-plan", Engineering Structures, 31, 1613-24, 2009.
3
R.E. Erkmen, M.A. Bradford, "Time-dependent creep and shrinkage analysis of composite beams curved in-plan", Computers & Structures, 89, 67-77, 2011.