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

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

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

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as expressed in the BCA.Species Average Density Typical Minimum Width(kg/m 3 ) (mm)Hardwood 800 100Softwood 550 140TABLE 16.11: Minimum beam thicknessesWhen determining the strength of the effective residual section take k 1 = 5 hours.16.7 Other FactorsThere are a number of other factors to be considered when assessing the structuraladequacy of a member designed to achieve a desired FPL in accordance with AS 1720.4 –2006. These are:Determination of Fire Resistance Period (FRP).The FRP may be required to:● determine a member size to satisfy Building Regulations;● check the effective residual section of an existing member against the FRP, i.e.against for example, 60/-/-.The FRP is determined by doing a series of successive iterations of time (t). FRP isreached when the effective residual section can no longer support the design load.Barrier JunctionsWhen included in a fire-resisting barrier a timber member has to have allowance made forthe effect the barrier junction has on the effective residual section. This effect is shown inFIGURE 16.4.Protected TimberFIGURE 16.4: Charring at junction with fire proof barrierTimber members with fire exposed surfaces protected by a fire-resistant insulation resultsin the fire resistance for structural adequacy of the timber member being increased. Toquantify this increase AS1720.4 modifies the fire resistance period thus:251

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