Question

Two beams of equal cross-sectional area are subjected to equal bending moment. If one beam has a square cross-section and the other has a circular cross-section

• A. Both beams will be equally strong
• B. Circular section beam will be stronger
• C. square section beam will be stronger
• D. the strength of the beam will depend on the nature of loading

Answer 1

Answer:

C. square section beam will be stronger

Section Modulus is a geometric property used in designing beams. The section modulus of a square section is stronger than a circular section with the same cross-sectional area. For a square section, $ZS = (\pi \sqrt{\pi} / 48) d ^ 3$ and for a circular section, $ZC = (\pi / 32) d ^ 3$