American Society of Civil Engineers

Long-Term Behavior of Wood-Concrete Composite Floor/Deck Systems with Shear Key Connection Detail

by M. Fragiacomo, (Assoc. Prof., Dept. of Arch. and Planning, Univ. of Sassari, Palazzo del Pou Salit, Piazza Duomo 6, 07041 Alghero, Italy; formerly, Sr. Lect., Dept. of Civ. Engrg., Univ. of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand. E-mail:, R. M. Gutkowski, (Full Professor, Dept. of Civ. Engrg., Colorado State Univ., Fort Collins, CO 80523-1372. E-mail:, J. Balogh, (Asst. Prof., Civ. Engrg. Technol., Metropolitan State Coll. of Denver, Campus Box 61, P.O. Box 173362, Denver, CO 80217-3362. E-mail:, and R. S. Fast, (Formerly, Grad. Res. Asst., Dept. of Civ. Engrg., Colorado State Univ., Fort Collins, CO 80523-1372)

Journal of Structural Engineering, Vol. 133, No. 9, September 2007, pp. 1307-1315, (doi:

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Document type: Journal Paper
Abstract: The paper investigates the long-term behavior of wood-concrete composite beams with notched connection detail. The experimental program comprised the characterization of the component materials (wood, concrete, and connection detail) and long-term tests on beam specimens. The beam specimens were monitored during the construction process, and for an overall period of 133 days after the application of the service load. The experimental results have then been extended to the entire service life of the structure using a one-dimensional finite-element model. It was found that the increase in moisture content due to the bleeding of the fresh concrete is not an issue for the durability of the wood deck, and the type of construction (shored or unshored) does not significantly affect the structural performance. The rheological phenomena experienced by the component materials lead to quite large deflections over the entire service life, whereas the variation in stress is not significant. If the limitation of the deflection is required for serviceability considerations, the use of concrete with reduced shrinkage and the precambering of the wood deck are to be recommended. A simplified approach based on closed form solutions for composite beams with smeared flexible connectors is finally proposed for the prediction of the long-term behavior.

ASCE Subject Headings:
Composite beams
Timber construction
Time dependence