12 TOWERS AXD TANKS FOR \V .VI l.k \\ORKS. 



at considerable length, for the purpose of comparison and for general 

 information, the Jacksonville, Fla., water-tower is shown in detail. 



Of a different class is the 20X120 foot stand-pipe designed 

 by the author and erected during 1897 in St. Augustine, Fla. 

 This structure is of the usual type, and has a capacity of 282,743 

 U. S. gallons. 



The tank was constructed of flange steel, and although 

 exposed to the heavy gales prevalent along the South Atlantic 

 Coast, and to the destructive effect of the salt atmosphere, after 

 fourteen years' sendee it is in excellent condition. 



A hemispherical -bottomed tank and steel tower also designed 

 and erected under the author's supervision is that shown in the 

 frontispiece. 



This was built in connection with the rehabilitation of the 

 water system at Wilmington, N. C., in 1910. 



The material for the tank was "flange steel" with ultimate 

 strength of 60,000 Ibs., with allowable variation of 5000 Ibs. 

 The bearing value of rivets was assumed at 12,000 Ibs. per square 

 inch. Tensile and shear strain of rods and pins was taken also 

 at 12,000 Ibs. with bending strain at 25,000 Ibs. per square inch. 

 The shear strain on the circular girder and horizontal thrust on 

 the lower flange ring was specified not to exceed 18,000 Ibs. PIT 

 square inch of metal. 



The stress in the circular girder was assumed as due to the 

 entire weight supported and the resultant horizontal thrust at the 

 top of the posts. The shear strain on the girder and the horizontal 

 thrust on the lower flange ring was not to exceed ten thousand 

 (10,000) pounds per square inch of metal. 



The conical cover was designed to safely resist the assumed 

 wind stress, but no cover plate was to be used less than one-eighth 

 (i) inch thick, and provision was made for reinforcement by 

 radial rafters, tie rods, or other means. 



The external pressure of the wind was calculated at 30 Ibs. 

 per square foot as exerted upon the vertical diametral plane of 

 the tank. The tower, consisting of six columns 115 feet high and 



