Experimental Investigation and Numerical Modeling of Tongue-and-Groove Plank Wood Decking under the Effects of Concentrated Loads

Tongue-and-groove plank wood decking is a product that is commonly used in post and beam timber construction to transfer gravity loads on roofs and floors. In 2010, the National Building Code of Canada changed the application area of the specified concentrated roof live loads from $750\times 750\mathrm{mm}$ to $200\times 200\mathrm{mm}$. Preliminary analysis showed that the change in the application area of concentrated loads would have a significant impact on the design of decking systems. An experimental program was undertaken at the University of Ottawa’s structural laboratory to better understand the stiffness characteristics of plank decking under concentrated loads. The experimental test program was complimented with a detailed finite-element model in order to predict the behavior of a plank decking system, especially the force transfer between decks through the tongue and groove joint. The study found that under concentrated loads, the stiffness of the decking system increased significantly as more boards were added. The number of boards found to be representative of a system was eight boards. A deflection coefficient of $\gamma =0.4$ was found to be appropriate to calculate the deflection for the simple span, two-span continuous, and controlled random layup, under concentrated load on an area of 200 by 200 mm. A finite-element model was created and compared with the experimental results, and it was found to predict the behavior with reasonable accuracy.