14.12 The timber box section (a) of Problem 14.29 is used as a simply supported beam on an 18-ft span length. The beam carries a uniformly distributed load of 500 lb/ft, which in- cludes its own weight. Calculate the maximum induced bending stress. 14.29 For the I-shaped timber beam shown, calculate the maxi- mum vertical shear force that will induce a maximum hori- zontal shear stress of 120 psi. Then calculate the shear stress in the plane of the junction between the web and the flange. Flange 10 Web- Flange 10