4. STRUCTURAL DESIGN OF LVL STRUCTURES 4.3.2 Shear For shear with a stress component parallel to the grain, see Figure 4.5(a, b, d and e), and for shear with both stress components perpendicular to the grain, see Figure 4.5 (c and f), the following expression shall be satisfied: τd ≤ fv,d (4.7) (EC5 6.13) where τd is the design shear stress; fv,d is the design shear strength for the actual condition. LVL is not sensitive to cracking and therefore the factor kcr =1,0. This means that the full member width b can be used in equation (4.8) of an effective width bef of the member in the verification of shear resistance of members in bending. bef = kcr ∙b (4.8) (EC5 6.13a) At supports, the contribution to the total shear force of a concentrated load F acting on the top side of the beam and within a distance h or hef from the edge of the support may be disregarded, see Figure 4.6. For beams with a notch at the support this reduction in the shear force applies only when the notch is on the opposite side to the support. For uniformly distributed loads, the determining shear force maybe taken at a distance of the member height h from the support. Figure 4.5. A) LVL-P shear stress edgewise parallel to grain B) LVL-P shear stress flatwise parallel to grain C) LVL-P shear stress flatwise perpendicular to grain (rolling shear) D) LVL-C shear stress edgewise parallel to grain E) LVL-C shear stress flatwise parallel to grain (rolling shear of cross veneers) F) LVL-C shear stress flatwise perpendicular to grain (rolling shear of parallel veneers). 2 1 A red h V V l l Figure 4.6. Conditions at a support, for which the concentrated force F may be disregarded in the calculation of the shear force. In the case of uniformly distributed loads, the shear force maybe reduced to the value which it has at a distance of the member height h from a support 31. d ≤ v, d (4.7) (EC5 6.13) ef = cr ∙ (4.8) (EC5 6.13a) d v, d (4.7) (EC5 6.13) ef = cr ∙ (4.8) (EC5 6.13a) D E B C F A LVL Handbook Europe 121
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