Commercial Building Inspector B2Structural SystemsEasy
A structural engineer is designing a concrete column for a multistory commercial building. The column is subject to both axial compression and bending moments. Which of the following interaction diagrams is most appropriate for evaluating the column's capacity under these combined loads?
- AAxial Load-Moment Interaction Diagram
- BStress-Strain Diagram
- CShear-Moment Diagram
- DMoment-Curvature Diagram
Show answer & explanationAnswer & explanation
Correct answer: A. Axial Load-Moment Interaction Diagram
An axial load-moment interaction diagram graphically represents the combinations of axial load and bending moment a column can safely resist. It is the primary tool for designing and analyzing concrete columns under combined forces.
Why the other options are wrong
- B. A stress-strain diagram describes the material's behavior under uniaxial loading, not the capacity of a structural element under combined forces.
- C. A shear-moment diagram is used for beams to show internal shear and bending moment distribution along the member.
- D. A moment-curvature diagram relates the applied bending moment to the resulting curvature of a cross-section, often used in nonlinear analysis.
Axial Load-Moment Interaction Diagram
A graphical representation showing the combinations of axial load (P) and bending moment (M) that a reinforced concrete column cross-section can safely resist without failure.
- Used for column design under combined P and M.
- Defines the strength limit states for a column.
- Each point on the curve represents a specific failure condition.
Memory trick: Columns P-M capacity, interaction shows its ability.