American Society of Civil Engineers


Laboratory Tests and Numerical Analyses of Prefabricated Timber-Concrete Composite Floors


by E. Lukaszewska, Ph.D., (corresponding author), (Dept. of Civil, Mining and Environmental Engineering, Luleå Univ. of Technology, 971 87 Luleå, Sweden E-mail: elzbieta.lukaszewska@ltu.se), M. Fragiacomo, (Associate Professor, Dept. of Architecture and Planning, Univ. of Sassari, Palazzo del Pou Salit, Piazza Duomo 6, 07041 Alghero, Italy. E-mail: fragiacomo@uniss.it), and H. Johnsson, Ph.D., (Dept. of Civil, Mining and Environmental Engineering, Luleå Univ. of Technology, 971 87 Luleå, Sweden. E-mail: helena.johnsson@ltu.se)

Journal of Structural Engineering, Vol. 136, No. 1, January 2010, pp. 46-55, (doi:  http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0000080)

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Document type: Journal Paper
Section Heading: Wood Structures
Abstract: This paper describes tests on a novel composite floor system constructed by connecting prefabricated concrete slabs to timber joists. Seven types of shear connectors have been developed and tested: lag screws, either alone or combined with a notch cut from each timber joist; metal plates embedded in the concrete slab and either nailed or glued to the joists; dowels embedded in the concrete and glued to the timber; and toothed metal plates embedded in the concrete and pressed into the timber. Four-point bending tests to failure were performed on five, full-scale, 4.8 m long specimens connected with lag screws or metal plates nailed to the timber. Values of deflection and relative slip between the concrete slab and the timber obtained in these tests showed high correspondence with values obtained from a uniaxial finite element model developed for nonlinear analyses of composite beams. The model was also used to perform a numerical analysis to failure of composite beams with the other four connection systems that were developed but not tested on full-scale specimens. The outcomes of the experimental tests and numerical analyses show that the newly developed system can provide good structural performance, especially if connections with coach screws and notches in the timber are used. The economic advantages of prefabrication and the possibility to disassemble the structure and reuse the timber beams and concrete panels at the end of the service life make the proposed floor system very promising.


ASCE Subject Headings:
Composite structures
Floors
Connections
Timber construction
Prefabrication
Precast concrete
Wood
Laboratory tests
Numerical analysis

Author Keywords:
Composite structures
Connectors
Timber construction
Prefabrication
Precast concrete
Wood