Question

The figure below shows the cross-section of a flitched beam consisting of a steel plate sandwiched between two wooden blocks. The second moment of area of the composite beam about the neutral axis XX is

• A. $\frac{b{h}^3}{12}+\frac{mt{h}^3}{12}$
• B. $\frac{b{h}^3}{12}+\frac{t(mh{)}^3}{12}$
• C. $(b+t)\frac{h^3}{12}$
• D. $\frac{b{h}^3}{12}$

Answer 1

The correct option is A $\frac{b{h}^3}{12}+\frac{mt{h}^3}{12}$

Moment of inertia of composite beam

$=I_w+m{I}_s=\frac{b{h}^3}{12}+\frac{mt{h}^3}{12}$