Modal Frequencies of a Reinforced Timber-Concrete Composite Floor: Testing and Modeling
Publication: Journal of Structural Engineering
Volume 141, Issue 11
Abstract
The reinforcement of a timber floor with a concrete layer properly connected to produce a composite system represents not only an improvement in the stiffness but also a foreseeable change in the modal frequencies of the floor. In order to assess that change, a typical timber floor, which was subsequently reinforced with a concrete layer to produce a composite, was tested at both stages in the research reported in this paper. Additionally, composite beams taken from the original floor were also tested. The results showed a significant decrease (44%) in the fundamental frequency after the reinforcement. In order to obtain the mode shapes and frequencies of the floor, finite-element (FE) models of the floors and beams were created. The FE models accurately matched the experimental results. Having validated the model, a parametric study was carried out to compare the results provided by the proposed FE model with a numerical model from the bibliography and to understand the influence of the most relevant structural parameters on the fundamental frequency of the composite floor.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers wish to thank the Portuguese Foundation for Science and Technology (FCT) and the Science and Innovation Operational Program cofinanced by the European Union Fund Fundo Europeu de Desenvolvimento Regional (FEDER), for the support provided through the Research Project No. PTDC/ECM/099833/2008.
References
Al-Foqaha’a, A., Cofer, W., and Fridley, K. (1999). “Vibration design criterion for wood floors exposed to normal human activities.” J. Struct. Eng., 1401–1406.
Bathon, L., Bletz, O., and Schmidt, J. (2006). “Hurricane proof buildings—An innovative solution using prefabricated modular wood-concrete-composite elements.” Proc., Ninth World Conf. on Timber Engineering, Oregon State Univ. Conference Services, Corvallis, OR.
Bernard, E. (2008). “Dynamic serviceability in lightweight engineered timber floors.” J. Struct. Eng., 258–268.
CEN. (2003). “Timber Structures—Structural timber and glued laminated timber—Determination of some physical and mechanical properties.”, Brussels, Belgium.
CEN. (2004a). “Eurocode 2—Design of concrete structures—Part 1-1: General rules, and rules for buildings.”, Brussels, Belgium.
CEN. (2004b). “Eurocode 5: Design of timber structures—Part 1-1: General—Common rules and rules for buildings.”, Brussels, Belgium.
Chuan, D., Fragiacomo, M., Buchanan, A., Crews, K., Haskell, J., and Deam, B. (2009). “Development of semi-prefabricated timber-concrete composite floors in Australasia.” NZ Timber Des. J., 17(1), 13–18.
Clough, R., and Penzien, J. (1993). Dynamics of structures, McGraw-Hill, New York.
Clouston, P., and Schreyer, A. (2008). “Design and use of wood-concrete composites.” Pract. Period. Struct. Des. Constr., 167–174.
Computers and Structures. (2011). CSI analysis reference manual, Berkeley, CA.
Deam, B., Fragiacomo, M., and Gross, S. (2008). “Experimental behavior of prestressed LVL-concrete composite beams.” J. Struct. Eng., 801–809.
Dias, A. (2012). “Analysis of the nonlinear behavior of timber-concrete connections.” J. Struct. Eng., 1128–1137.
Dias, A., Cruz, H., Lopes, S., and Kuilen, J. (2010a). “Stiffness of dowel-type fasteners in timber-concrete joints.” Proc. Inst. Civ. Eng. Struct. Build., 163(4), 257–266.
Dias, A., Kuilen, S., Cruz, H., and Lopes, S. (2010b). “Numerical modeling of the load-deformation behavior of doweled softwood and hardwood joints.” Wood Fiber Sci., 42(4), 480–489.
Dias, A., Lopes, S., Kuilen, J., and Cruz, H. (2007). “Load-carrying capacity of timber-concrete joints with dowel-type fasteners.” J. Strut. Eng., 720–727.
Dias, A., Monteiro, S., and Martins, C. (2013). “Reinforcement of timber floors—Transversal load distribution on timber-concrete systems.” Adv. Mater. Res., 778, 657–664.
Dolan, J. D., Murray, T. M., Johnson, J. R., Runte, D., and Shue, B. C. (1999). “Preventing annoying wood floor vibrations.” J. Struct. Eng., 19–24.
Fragiacomo, M., and Lukaszewska, E. (2011). “Development of prefabricated timber-concrete composite floor systems.” Proc., Structures and Buildings, Institution of Civil Engineers, London.
Gelfi, P., Giuriani, E., and Marini, A. (2002). “Stud shear connection design for composite concrete slab and wood beams.” J. Struct. Eng., 1544–1550.
Ghafar, A., Deam, B. L., Fragiacomo, M., and Buchanan, A. (2008). “Vibration performance of LVL-concrete composite floor systems.” Proc., World Conf. on Timber Engineering, Engineered Wood Products Association, Australia.
Girhammar, U. A, Pan, D. H., and Gustafsson, A. (2009). “Exact dynamic analysis of composite beams with partial interaction.” Int. J. Mech. Sci., 51(8), 565–582.
Girhammar, U. A., and Pan, D. H. (1993). “Dynamic analysis of composite members with interlayer slip.” Int. J. Solids Struct., 30(6), 797–823.
Glisovic, I., and Stevanovic, B. (2010). “Vibrational behaviour of timber floors.” Proc., World Conf. on Timber Engineering, Trees and Timber Institute, National Research Council, Italy.
Khorsandnia, N., Valipour, H. R., Shrestha, R., Gerber, C., and Crews, K. (2013). “Review on long-term behaviour of timber-concrete composite floors.” From materials to structures: Advancement through innovation, B. Samali, M. M. Attard, and C. Song, eds., Taylor and Francis, London, 1053–1058.
Ljunggren, F., Wang, J., and Agren, A. (2007). “Human vibration perception from single- and dual-frequency components.” J. Sound Vibr., 300(1–2), 13–24.
LNEC (Laboratório Nacional de Engenharia Civil). (1995). “Structural maritime pine sawn timber—Visual grading.”, Portugal (in Portuguese).
Lukaszewska, E., and Fragiacomo, M. (2010). “Static and dynamic (vibration) performance of composite beams with prefabricated concrete slab.” Proc., World Conf. on Timber Engineering, Trees and Timber Institute, National Research Council, Italy.
Mertens, C., Martin, Y., and Dobbels, F. (2007). “Investigation of the vibration behaviour of timber-concrete composite floors as part of a performance evaluation for the Belgian building industry.” Build. Acoust., 14(1), 25–36.
Ohlsson, S. (1995). “STEP lecture A18: Serviceability limit states—Vibration of wooden floors.” Timber engineering STEP 1, Centrum Hout, Almere, Netherlands.
Rijal, R. (2013). “Dynamic performance of timber and timber-concrete composite flooring systems.” Ph.D. thesis, Faculty of Engineering and Information, Sydney School of Civil and Environmental Engineering, Sydney Univ. of Technology, Sydney, Australia.
SAP 2000 version 15.1.0 [Computer software]. Berkeley, CA, Computers and Structures.
Skinner, J., et al. (2014). “Concrete upgrade to improve the vibration response of timber floors.” Struct. Build., 167(9), 559–568.
Skinner, J., Harris, R., Paine, K., and Walker, P. (2011). “Considerations for the inclusion of the expressions in Eurocode 5 to assess the vibrational performance of timber-concrete composites.” Proc., Conseil International dû Batiment W18, Ingenieurholzbau und Baukonstruktionen, Karlsruhe Institute of Technology, Germany.
Smith, I., and Chui, Y. H. (1988). “Design of lightweight wooden floors to avoid human discomfort.” Can. J. Civ. Eng., 15(2), 254–262.
Weckendorf, J., Zhang, B., and Kermani, A. (2010). “Prediction of modal frequencies, modal shapes and static point load deflections of I-joist timber flooring systems using finite element method.” Proc., World Conf. on Timber Engineering, Trees and Timber Institute, National Research Council, Italy.
Wu, Y., Xu, R., and Chen, W. (2007). “Free vibrations of the partial-interaction composite members with axial force.” J. Sound Vibr., 299(4–5), 1074–1093.
Xu, R., and Wang, G. (2012). “Variational principle of partial-interaction composite beams using Timoshenko’s beam theory.” Int. J. Mech. Sci., 60(1), 72–83.
Xu, R., and Wu, Y. (2007). “Static, dynamic, and buckling analysis of partial interaction composite members using Timoshenko’s beam theory.” Int. J. Mech. Sci., 49(10), 1139–1155.
Yeoh, D., Fragiacomo, M., De Franceschi, M., and Boon, K. (2011a). “State of the art on timber-concrete composite structures: Literature review.” J. Struct. Eng., 1085–1095.
Yeoh, D., Fragiacomo, M., De Franceschi, M., and Buchanan, A. (2011b). “Experimental tests of notched and plate connectors for LVL-concrete composite beams.” J. Struct. Eng., 261–269.
Information & Authors
Information
Published In
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Apr 14, 2014
Accepted: Jan 7, 2015
Published online: Feb 19, 2015
Discussion open until: Jul 19, 2015
Published in print: Nov 1, 2015
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.