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

Figure 6.4: Shows major and minor axes of bendingStrength Limit State:Strength Limit StateDesignActionEffectBending M*Design CapacityStrength Limit StateSatisfied when: ΦM=ΦM > M*Φk 1 k 4 k 6 k 9 k 11 k 12 [f’ b Z]AS1720.1-1997Referenceclause 3.2.1.1For beams that can bend about both the major and minor axes M * M *x ysimultaneously: + ≤1.0( φMx) ( φMy) ΦV=Shear V*ΦV > V*k 1 k 4 k 6 k 11 [f' s A s ] p ΦN= ΦBearingN*perpendicular to grainp k 1 k 4 k 6 k 7 [f' p A p ]ΦNp > N* pparallel to grainN*lk 1 k 4 k 6 [f' l A l ]l ΦN= Φclause 3.2.1.2clause 3.2.5clause 3.2.6.1ΦN l > N* l clause 3.2.6.2where:b, f' s , pM * , V * , N * p , N l = Design action effect in bending, shear and bearing respectivelyΦM, ΦV, ΦNp, ΦN l = Design capacity in bending, shear and bearing respectively*M x , M * y = Design action effect in bending about the major principal x-axisand minor principal y-axis.ΦM x , ΦM y = Design capacity in bending about the major principal x-axis andminor principal y-axis.Φ = Capacity factor for LVLk 1 = Duration of load strength modification factork4= Moisture condition modification factork6= Temperature modification factork7= Length of bearing modification factork9= Strength sharing modification factork11= Size modification factork12f'= Stability modification factorf'= Characteristic strengths in bending, shear and bearingrespectivelyZ = LVL beam section modulus =I p /ypAs= shear plane area = 2/3(bd) for a beam loaded about its major axisin bendingA p, A l = bearing area under the design load perpendicular and parallel tothe grain as shown in FIGURE 6.5.40