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

FIGURE 11.4: Position of critical plane for rolling shearTo determine the magnitude of the rolling shear at the critical interface requiresapplication of the formula:τSQ=1.bss(11.1)where:S = applied shear force in Newtons;Q s = first moment of the area of the parallel to stringer pliesoutside the critical plane as shown in FIGURE 11.4;I = gross second moment of area of the panel in mm 4 ;b = sum of widths of stringer glued surfaces in mm;s11.5 Panel Design – MethodologyThe design method presented in this Manual is based on the approach given by the Engineered WoodProducts Association of USA (formerly APA).Trial SectionChoose a trial section based on experience or by taking a single beam element as a model. If the lattermethod is chosen keep in mind the final element will be 1200 mm wide and stiffened by top and bottom skins.Be mindful of the following design parameters when choosing the trial section:• maximum stringer spacing 600mm;• minimum thickness of tension skin 7mm;• basic spacing (b) between stringers should be equal to 45 or 50 x plywood thickness;• for effective width of plywood to be full width (b) ≥ (), the clear spacing between stringers146