7 'HE STRESSES IN A STEEL WATER-TOWER. 



127 



just obtained for the four points of support, are summarized in 

 the following table: 



STRESSES IN THE CIRCULAR GIRDER. 



In the above table W is the total weight supported by the 

 girder in pounds, and r is the radius of the girder in inches. 



Stresses in the Posts. It was shown in the consideration of 

 the circular girder that the vertical load on the top of a pest is 

 the total weight of the circular girder, the tank andf its contents 

 divided by the number of posts. In addition to this load the 

 posts of each story must carry the weight of posts, struts, and 

 ateral rods of the stories above it. Thus 

 the vertical load on any one section or story 

 of the post is readily determined. Let me 

 vertical load on the section under considera- 

 tion be W. If the post is vertical, the com- 

 pression in it equals W. If the post is 

 inclined, the compression becomes 



C=TFsec $, (Fig. 28,) 



<f> being the angle of inclination of the post 

 from the vertical. The vertical reaction at 

 the base of the post equals W. To maintain equilibrium there 



w 



FIG. 28. 



