Question

A short hollow $CI$ column section $A$ is $150c{m}^2$ and the section modulus $Z=10\times {10}^{5}m{m}^3$ carries
(i) an axial load of $250kN,$ and
(ii) a load of $50kN$ on a bracket, the load line being $500mm$ from the axis of column
The maximum and minimum stress intensities are

• A. $50N/m{m}^2$ tensile and $10N/m{m}^2$ compressive
• B. $45N/m{m}^2$ compressive and $5N/m{m}^2$ tensile
• C. $55N/m{m}^2$ compressive and $5N/m{m}^2$ tensile
• D. $60N/m{m}^2$ tensile and $10N/m{m}^2$ compressive

Answer 1

The correct option is B $45N/m{m}^2$ compressive and $5N/m{m}^2$ tensile

Axial stress $=\frac{(250+50)\times {10}^3}{150\times 100}=20N/m{m}^2$
Bending stress $=\frac{50\times {10}^3\times 500}{10\times 10}=25N/m{m}^2$
Maximum sress $=20+25=45N/m{m}^2$ (comp.)
Minimum stress $=20-25=-5N/m{m}^2$ (tens.)