Stresses in Tower Shell

Sf = unit stress in tower shell due to bending moment,, lbs. per sq. ft. 

Note The unit stress in the tower shell, is calculated in pounds per square foot to be consistent with the other calculations which are in footpound units. Steel stresses, however, are ordineirily given in pounds per square inch. To convert the stress from lbs. as calculated to sq. in., it is necessary to divide Sf by 144. 

This value of S is the total unit stress at any point whose distance (in feet) from the centroidal axis is c.  

It is important to note that equation developments were used to determine the stability and the eccentricity under the poorest condition, which obviously occurs when the dead load is at its minimum. Equation (ll-28a) can be used to determine the stress under any dead load. Therefore, equation (ll-28d) may be based on either W or Wt depending on the dead load for which the stress is to be determined. 

The steel shell is required to withstand the stresses resulting from, (a) the internal pressure (b) the dead load, and (c) the overturning moment from wind pressure. This discussion will be confined to the stress resulting from the wind pressure. 

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See sections on Stresses in Tower Shell and Foundation Bolts for Self-Supporting Tower. ... 

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