Question

3. Without writing shear and moment equations, draw shear and moment diagrams and indicate the values at all critical locations. 20 kN 40 kN/m 20 kN/m 1.2m 4m 4m

Answer 1

Given, shear and moment diagrams load calculations Triangular loading delta = F_1 = 1/2 times 20 times 1.2 = 12 kN x_16bar = 2/3 (1.2) = 0.8 m small rectangular load F_2 = 20 times 9 = 80 N x_2^bar = 1.2 + 2 = 3.2 m Large rectangular load F_3 = 40 times 4 = 160 kN x_3^bar = 1.2 + 4 + 2 = 7.2 m Free body diagram sigma V = 0 R_B + R_D = 20 + 12 80 + 160 = 272 kN sigma M_D = 0 20 times 9.2 + 12 times 8.4 - R_B times 8 + 80 times 6 + 160 times 2 = 0 R_B = 135.6 kN R_D = 137 kN shear force calculations (S.F)_A = 20 kN (S.F)_B left = 20 - 135.6 + 12 = -103.6 kN (S.F)_B right = -103.6 + 135.6 = 32 kN (S.F)_C left