EWPAA Structural Plywood and LVL Design Manual - Engineered ...

7 Basic Structural Plywood & LVL BuildingComponents7.1 IntroductionEWPAA product certified structural plywood and LVL products are used extensively in residential,commercial and industrial building components. Dimensional uniformity and trueness, and reliable,consistent structural properties, make them an attractive material choice from both a design and constructionperspective. Basic structural plywood components include flooring of all types (domestic, commercial,industrial, sport floors and containers), bracing, combined wall cladding and bracing, and roof sheathing.The use of structural plywood as residential flooring, bracing and non-trafficable roofing is detailed inAS1684 Residential Timber-Framed Construction Code which is deemed to comply under State buildingordinances and the Building Code of Australia. Structural LVL and plywood/LVL I-beams are used inframing elements as bearers, joists, lintels and roof framing. Due to the extensive usage of these productswithin the building industry, specific technical literature has been developed for each application and isavailable either from the Engineered Wood Products Association of Australasia or EWPAA manufacturingmembers.7.2 Structural Plywood Flooring and Floor SystemsStructural plywood has a number of inherent characteristics which make it particularly suitable for useas a platform flooring material. It has defined and standardised structural properties, good dimensionalstability compared to other timber panel products, tongued and grooved edges eliminating the need fornogging, a permanent Type A phenolic bond and high strength and stiffness capacity suitable for useunder the higher design loads required by the building codes for commercial and industrial flooring.Floor live load requirements for a range of building occupancies are given in AS1170 SAA StructuralDesign Actions – Part 1: Permanent, imposed and other actions.7.3 Design Issues of FlooringThe excellent load re-distribution capabilities of plywood means uniformly distributed loads are unlikelyto govern the design. Structural plywood flooring design is usually governed by the concentratedimposed loads. For more lightly loaded floors deflection under imposed concentrated loads governsplywood selection. Shear strength may govern under higher concentrated loads with closer supportspacings. Concentrated loads on structural plywood flooring are treated as a line load. The distributionwidth of the concentrated load must therefore be determined. TABLE 5.3 in Error! Reference source notfound. of this Manual provides standard load distribution widths for various thicknesses of plywood.Structural plywood flooring should be spanned with the face veneer grain direction parallel to the span tomaximise the plywood capacity. Support spacings should be selected to suit the plywood sheet length,such that the ends of the sheet land on a support.Note closer support spacings with thinner plywood will usually be a more economical solution than widely spacedsupports with thicker plywood. Long edges of structural plywood flooring are usually manufactured with plastictongue and groove. The tested capacity of the tongue and groove for EWPAA branded plywood, under concentratedload is 7.5 kN. If tongued and grooved edges are not used, or where the concentrated load exceeds 7.5 kN,support must be provided to long edges. Finally, in applications where the plywood surface will be subject toabrasive loadings such as may occur in garage floors and industrial floors subject to wheeled traffic there, may bea need for some surface protection.54