Question

Actual Size Nominal Size Weight (b/m) (kg/m) (in x in) (in x in) (mm x mm) 1 x 1 3/4 x 3/4 19x 19 0.14 1 x2 3/4 x 1 1/2 19 x 30 0.27 1 x3 3/4 x 2 1/2 19 x 64 0.47 1 x4 3/4 x 3 1/2 19 x 89 0.64 1 x 6 3/4 x5 1/2 19x 140 1.00 1x8 3/4 x7 1/4 19x 184 132 19 x 235 19 x 286 1 x 10 3/4 x 9 1/4 1.69 1 x 12 3/4 x 11 1/4 2.05 2 x2 2 x3 2 x4 2 x6 2x8 1 1/2 x1 1/2 38 x 38 0.55 1 1/2 x 2 1/2 38 x 64 0.94 1 1/2 x3 1/2 38 x 89 1.28 1 1/2 x5 1/2 1 1/2 x7 1/4 38 x 140 2.00 38 x 184 2.64 2x 10 1 1/2 x9 1/4 38x 235 3.37 2x 12 1 1/2 x 11 1/4 38 x 286 4.10 2x 14 1 1/2 x 13 1/4 38 x 337 4.83 BCI Joists BCI 60 2.0 1IC BCI 5000 1.7 BCI 6000 1.8 BCI 90 2.0 11½I BCI 6500 1.8 1 D 1 IG 1" IO 94 11%" 14" 16 9 11%" 14 16" 9/2 11%" 14 16" 11% 14" 16" 11%" 14" 16" 18" 20 2 2%%6" 2%16" 2A6* 3/4" 1. See the data table for uniform load and length values. The joist is generally treated as a simply supported beam. Joist length=17 ft., Load = 117 lb/ft a. Determine the reactions, shear diagram, moment diagram and the maximum moment from your moment diagram. b. Assuming the sawn lumber size is 2x14, state or determine the location of the area centroid and calculate the moment of inertia, I. Note that joists are oriented so that the long side is perpendicular to the sheathing. c. Determine the maximum bending stress in the joist. d. Assume the BC_6500 I-joist. Choose one of the depths and identify the area centroid and calculate the moment of inertia, I. e. If the floor joists were made from the I-joist from 1d determine the maximum bending stress in the l-joist due to the maximum moment from the moment diagram. f. If the maximum bending stress is 1500 psi does either joist break?

Answer 1

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