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

Z(NA) perpendicular to face grain=I(NA)strength perpendiculary2where y 2 is the distance from neutral axis to the outside of the farthest veneer parallel to the span (seeFIGURE A5.2An Equivalent AlternativeThe previously presented method of determining (I) is necessary if, and only if the:• lay-up results in an unbalanced section, i.e. there are different thicknesses either side of thegeometrical centre of the cross-section;• species either side of the geometrical centre of the cross-section are different requiring the applicationof the transformed section concept.For a balance cross-section as shown in FIGURE A5.1 (I) can be evaluated fairly easily by applying thegeneralised relationship:where:33= bD∑ − bdINA 12 12A1.5.4b = width of section (mm);D = depth of major thickness being considered (mm);d = depth of section to be removed (mm).Applying Equation 5.4 to the cross-section shown in FIGURE A5.1 , for face grain parallel to the span:3bD3bd3 bdI3NA= − +12 12 12Referring to FIGURE A5.2 for face grain perpendicular to the span:INAbD3=12bd3−31236