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

name is used to identify the particular suite of engineering properties unique to their product.Therefore, when specifying a structural LVL product, the brand name assigned by the manufacturer totheir product must also be included in any specification for LVL products.Generally, design of structural LVL elements and components is similar to that for sawn timber.However, structural LVL is differentiated from sawn timber due to its engineered nature achieved byrandomising any naturally occurring timber characteristics throughout the member and a high degree ofprocess control during manufacture. The end product has highly predictable structural properties with alow co-efficient of variation of these properties. These attributes are reflected in the assignment tostructural LVL of the highest possible capacity factor under the Timber Structures Code AS1720.1-1997.Structural LVL is manufactured as a seasoned, dimensionally uniform product and for best results,the product should be stored and utilised on site to minimise exposure to moisture.7.13 Design Example – LVL Lintel Beam - SpecificationDesign and specification for a structural lintel beam supporting roof loads over doors, in a residentialapplication, in a C1 Cyclonic wind classified area. Lintel beam will be Best By Far (BBF) brand LVL.Characteristic Strengths and Elastic Moduli, MPa for BBF LVL aspublished by the manufacturer of BBF brand LVLBending f’ 45 MPabTension f’ 31 MPatShear in beams f’ 5.3 MPasCompression parallel to grain f’ 43 MPacCompression perpendicular to grain f’ p 11 MPaModulus of Elasticity E 12400 MPaModulus of Rigidity G 620 MPaJoint GroupJD4Specification for the LVL lintel beam is as follows:1. Design criteria:• Lintel beam is a single span of 3.6m.• Lintel beam is supporting rafter loads input as discrete point loads at 900mm centres.• Roof and ceiling loads are 40 kg/m 2 .• Roof load width is 4.8m.• Adequate clearance must be maintained over doors. Therefore set deflection limit asfollows:o Permanent Loads:Span/300 to 9 mm maximumo Imposed Loads: Span/250 to 9 mm maximumo Downwards Wind Loads:Span/250 to 9 mm maximumo Wind Uplift:Span/100 to 50 mm maximum2. LoadsPermanent:2Roof & Ceiling load = 40kg/m(40 x 9.81 x 4.8m x 0.9m) x10= 1.7kN/rafter3Self weight allow 650kg/m-3Select Trial size beam 300 x 45 mmSelf weight = 65 x 9.81 x 0.3 x.045= 0.09 kN/mImposed:1.4 kN concentrated imposed load (Assume live load directly over centre rafter)Partial Imposed Loads: 0.25 kPa(Assumed spread over 3.6m width of lintel and64AS/NZS 1170.1,Table3.2