A rectangular shape of stress distribution diagram at the base of a circular chimney is shown in figure. By referring to it, it may be concluded that:________

Explanation:

Stress distribution diagram at the base of a circular chimney:

Wind pressure(P) acting on the chimney

• Let wind pressure(P) kN/m2 act on the left side of the chimney 
• the height and diameter of the chimney are h and D respectively.
• The direct stress is the same base on the chimney because the weight or load of the chimney is uniformly distributed in the base area.

\(Direct\:stress(\sigma _{d}) = \frac{Weight\:of\:Chimney(W)}{Area\:of\:chimney(A)}\)

• Bending stress at the base of the chimney due to wind pressure  

\(Bending\:stress(\sigma _{b}) = \frac{M}{Z}\)

Where

M = Moment generated due to wind pressure

Z = Section modulus of chimney

Let the maximum stress at the base of the chimney be σ_max and the minimum stress at the base of the chimney be σ_min.

_{\(\sigma_{max} = \sigma _{d} + \sigma _{b} \\ \sigma_{max} = \sigma _{d} - \sigma _{b} \)}

• As the question σmax is equal to  σmin , we can conclude that there is no bending force occurring due to wind action and hence only force acting on base is its own dead load(direct compressive load) and the stress diagram will look like below