Footing Bending Moment at Column Face
Mediumfootingbending-momentcantilever
A 2.4 m square footing carries a centered 0.4 m square column. The uniform net factored upward pressure is 150 kPa. Treat a 1.0 m wide strip projecting outward from the column face as a cantilever; the critical bending section is the column face. What is the bending moment per meter width at that face?
- A75 kN·m/m
- B432 kN·m/m
- C150 kN·m/m
- D36.75 kN·m/m
Show solutionHide solution
Answer: A. 75 kN·m/m
Equation: M = wℓ²/2, with w = qu,net × 1.0 m. Inputs: ℓ = (2.4 − 0.4)/2 = 1.0 m; w = 150 kN/m. Substitution: M = 150(1.0)²/2 = 75 kN·m/m. Wrong: 432 kN·m/m uses the full 2.4 m width as the cantilever length; 150 kN·m/m uses wℓ (force times full length rather than resultant at ℓ/2); 36.75 kN·m/m evaluates at the shear section d = 0.3 m from the face (ℓ = 0.7 m) rather than the face.
kN·m/m
Practice this deckUntimed, one problem at a time, with your progress saved.
Related problems
- Fixed Support Moment of a Cantilever · Beam Analysis
- Max Moment in a Cantilever Beam · Beam Analysis
- Punching Shear Force on a Footing · Concrete: Columns, Slabs & Footings