A simply supported beam spans 6 m and carries a single 20 kN point load at midspan. Neglecting self-weight, the maximum bending moment in the beam is most nearly:
Worked solution
1. By symmetry each reaction is R = P/2 = 10 kN.
2. Shear is constant at 10 kN from the support to midspan, so the moment grows linearly to its peak under the load.
3. Mmax = R · L/2 = 10 kN × 3 m = 30 kN·m.
Handbook check: PL/4 = 20 × 6 / 4 = 30 kN·m.

