00078 Lin Hu - Timber Design Society

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1kN static deflection calculated using Eq.2 (mm) 3.2.5 Verification Figure 11 shows a comparison of predictions using the proposed new design methodology to predict the CLT floor vibrations and corresponding subjective ratings by evaluators. 2.00 1.50 1.00 0.50 Predicted CLT floor vibration performance vs. subjective ratings criterion ( f/d^0.7>13.0) Unacceptable Marginal Acceptable 0.00 0 5 10 15 20 Fundamental Natrual frequency calculated using Eq. 1 (Hz) Figure 11: Predicted CLT floor vibration performance by the proposed design method vs. subjective rating by participants 3.2.6 Simple Form of the Design Method Inserting Equations (2) and (3) into the design criterion, i.e. Equation (1), it is possible to obtain a simple form of the design method which can be expressed by Equation (4) as given below. l 1 9.15 ( EI 1m 0.293 eff 0.123 ( A) ) (4) Using Equation (4), it is possible to determine the vibration controlled spans for CLT floors directly from the effective apparent stiffness in the span direction, density and cross-section area of 1m wide CLT panels. 3.2.7 Impact Study The vibration controlled CLT floor spans determined using the proposed design method were compared with the spans determined by CLTdesigner developed at university of Graz in Austria [4]. Table 1 provides the comparison. Table 1: Vibration controlled CLT floor spans determined using the new design method vs. the spans determined by “CLTdesigner” CLT Thickness (mm) Span Determined by the Proposed Method (m) Span Determined by “CLTdesigner” for 1% Damping 100 3.58 3.53 120 3.76 3.75 140 4.50 4.43 160 4.80 4.76 180 5.16 5.14 200 5.68 5.67 220 5.84 5.89 240 6.09 6.17 As given in Table 1, the vibration controlled spans of bare CLT floors predicted by this new design method were very close to those spans determined by CLTdesigner. 4 CONCLUSIONS It is concluded that the proposed design methodology to determine vibration-controlled maximum spans of bare CLT floors is promising. This methodology uses only the design values of CLT mechanical properties. The method is simple, user-friendly, and reliable. Wide acceptance of the proposed design method relies on the use and evaluation of the method by productmanufacturers and designers. FPInnovations is open to feedback and ready to adopt and further refine the design method according to the needs of the producers and designers. The current form of the design method is for CLT floors without heavy topping. A study of the effect of heavy topping on the vibration performance of CLT floors is under way. ACKNOWLEDGEMENT FPInnovations would like to thank its industry members and Natural Resources Canada (Canadian Forest Service) for their financial support of this work. The authors wish to thank KLH for providing CLT panels for this study and the guidance on CLT floor construction. Thanks are also extended to Mr. Thomas Orskaug of Moelven Massivtre AS (Now of KLH Solid Wood Scandinavia AB) and Dr. Anders Homb of SINTEF Byggforsk for sharing their experience of massive wood slab non-joisted floor systems with us and for providing the opportunity to visit CLT buildings in Norway. Thanks are also extended to Dr. Gerhard Schickhofer of Graz Institut für Holzbau und Holztechnologie, Austria for conducting the comparison given in Table 1.
REFERENCES [1] Hu J.: Design guide for wood-framed floor systems. Final report No.32 for Canadian Forestry Service. FPInnovations, Quebec, 2007. [2] Homb A.: Vibrasjonsegenskaper til dekker av massivtre (in Norwagien). Report of Prosjektrapport 24, Sintef Byggforsk, Norway, 2008. [3] Hu J.: Protocols for field testing of wood-based floor systems. Appendix V in Report of Serviceability design criteria for commercial and multi-family floors. Report No. 3 for Canadian Forest Service, FPInnovations, Quebec, 1998. [4] Schickhofer G.: Comments on FPInnovations new design method for CLT floor vibration control. Private e-mail provided the link to access to CLTdesigner,2010: http://www.cltdesigner.at/webstart/testversion/cltdes ignertestversion.jnlp
Page 1 and 2: CONTROLLING CROSS-LAMINATED TIMBER
Page 3 and 4: 2.2.2 Subjective Evaluation The key
Page 5: 3 RESULTS 3.1 KEY CONSTRUCTION AND

00078 Lin Hu - Timber Design Society

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