PROBLEMS

P$\mathrm{.}12\mathrm{.}1$ A timber beam $200$ mm wide by $300$ mm deep is reinforced on its top and bottom surfaces by steel plates each $12$ mm thick by $200$ mm wide. If the allowable stress in the timber is $8\frac{N}{m}{m}^2$ and that in the steel is $110\frac{N}{m}{m}^2,$ find the allowable bending moment. The ratio of the modulus of elasticity of steel to that of timber is $20.$