Question

The allowable bending stress is σ1ow-22 ksi and the allowable shear stress is Tallow 12 ksi. (Figure 1) Part A Select the lightest steel wide-flange beam from Appendix B that will safely support the loading shown. If there are several choicas of equal weight, choose the one with the shortest height. w14 × 26 W8 x 31 W10 × 39 w12 × 22 W12 × 26 W14 x 22 W10 × 30 W8 × 40 Submit Request Answer Figure 1 of 1 Return to Assignment Provide Feedback 10 kip 4 kip 6 kip 4 ft 4 ft 4 ft

Answer 1

R_A + R_B = 20 rightarrow(1) sigma M_A + uparrow = 0 16R_B - 4 times 4 - 10 times 8 - 6 times 12 = 0 R_B = 10.5 kip R_A = 9.5 kip\r\n Maximu B Bending moment will be at mid point M = 9.5 times - 4 times 4 M = 60 kip maximum share Force = F F = 10.5 kip Now M/I = bellow/y^- 60/bd^3/12 = 22/d/2 60 times d/2 = bd^3/12 times 22 bd^2 = 16.36 rightarrow (1) Also Tallow = F.A y^-/I,b y^- = d/2 A = b times d 12 = 10.5 times b times d^- times d^-/2/bd^3/12 times b\r\n 12 times bd/12 = 10.5/2 bd = 5.25 rightarrow (II) From I and II bd^2 = 16.36 (bd) d = 16.36 (5.25)d = 16.36 d = 3.116 ft b = 5.25/3.116