CHAPTER VI. 



THE STRESSES IN A STEEL WATER-TOWER.* 



IT is the purpose of this chapter to collect and reduce to 

 convenient working form the formulae required in solving the 

 stresses in a steel water-tower. A water-tower is understood 

 to be a water-tank and the tower or trestle supporting it. The 

 tower may have three or more posts. It is assumed that the 

 posts are spaced equidistant, i.e., at the corners of a regular 

 polygon. The tank is cylindrical. Its bottom may be flat, 

 conical, or spherical. The flat bottom is rarely used in important 

 structures and will not be considered. 



The forces acting on a water-tower are gravity and wind 

 pressure. These forces or loads must be transmitted by the 

 structure from the points of application to the points of support 

 or foundations. In the discussion following, the loads will be 

 traced from their points of application to the foundations, and 

 the resulting stresses in the successive members or parts of the 

 structure determined. Secondary stresses, i.e., " local stresses 

 resulting from details of construction, will not be considered. 



GRAVITY STRESSES. 



The force of gravity acting on a water-tower equals the 

 weight of the structure plus the weight of the water supported 

 by it. The weight of the proposed water-tower may be deter- 



* By H. J. Burt. Revised from paper in The Technograph, No. 16, 1901-2, 

 University of Illinois. 



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