Shear Force and Bending Moment Diagram for Cantilever Beam with Three Point Load

Data:

L = 3m

W1 = 10kN

W2 = 20kN

W3 = 20kN

Solution:

Maximum S.F = 10 + 20 + 20 = +50kN

Shear at support AB = -10kN

Shear at support BC = -(10 + 20) = -30kN

Shear at support CD = -(10 + 20 + 20) = -50kN

                                        Shear Force Diagram

Maximum B.M = -WL

Moment at support A, M_A = 0kN.m

Moment at support B, M_B = -(10 x 1) = -10kN.m

Moment at support C, M_C = -[(10 x 2) + (20 x 1)] = -40kN.m

Moment at support D, M_D = -[(10 x 3) + (20 x 2) + (20 x 1)] = -90kN.m

                                                         Bending Moment Diagram

Result:

Max S.F = +50kN

S.F at AB = -10kN

S.F at BC = -30kN

S.F at CD = -50kN

Max B.M

M_A = 0kN.m

M_B = -10kN.m

M_C = -40kN.m

M_D = -90kN.m