Analysis of K-factor for five-ply plywood

Abstract

K-factor has long been used as a modifier of section modulus in the calculation of bending moment for plywood beams. No comparable modification of moment of intertia is included in current recommendations for calculating plywood deflection at span-depth ratios of 30:1 or greater. Results of limited testing lend support to the authors' contention that, where "shear" strains are significant, the same K value would be appropriate for predicting both the deflection and bending moment of plywood. If these results are confirmed by further investigation, a method for determining an appropriate value for k based on separate calculations of deflections due to shear and bending is suggested.

Citation

Wangarrd, F.F.; Woodson, George E.; Wilcox, William R. 1973. Analysis of K-factor for five-ply plywood. Forest Products Journal, Vol. 23(4): 55-57