Solving For Internal Forces:
1. Draw the Shear and
Moment Diagram.
2. Determine Maximum
Shear and Bending Moments
on Beams
Sample Beam Element:
Example:
1. Draw the Shear and Moment Diagram
2. Determine the maximum shear and           36 kN/m
bending moment of the beam shown.
                                       a               b             c
                                            9m                  3m
         =0
                                       Ra                  Rb
   36(12)(6) – Rb(9) = 0
   Rb = 288 kN
         =0
   36(12) – (Ra + Rb) = 0
   Ra = 144 kN
Example:
1. Draw the Shear and Moment Diagram
2. Determine the maximum shear and                                36 kN/m
bending moment of the beam shown.
                                        a                                      b                     c
                                                                 9m                           3m
   Shear
   1) 144 kN                                        144 – 36(X) = 0
   2) 144 – 36(9) = -180 kN (Vmax)       Ra                                         Rb
                                                    X= 4
   3) -180 + 288 = 108 kN
   4) 108 – 36(3) = 0 kN               144                                    108
                                             0.5(144)(X)
                                                                                       0.5(108)(3)       0
   Moment                                                  288        0.5(-180)(9-X)
   2) ½(144)(X) = 288 kN-m
                                                                                         -180
   3) 288 + ½(-180)(9-X) = -162 kN-m
                                        0                                                                0
   4) -162 + ½(108)(3) = 0 kN-m
                                                                             -162