10 TOWERS AND TANK'S FOR WATER-WORKS. 



water-plants, is 161, generally constructed since 1890. The 

 modern practice is to build them largely of structural or soft 

 steel, and although the procurable data is not so full or com- 

 plete as the records of stand-pipes in the United States, the 

 general average diameter, height, and capacity is as follows: 

 Diameter, 21.3; height, 36.9; capacity, 101,100 U. S. gal- 

 lons, supported upon some form of trestle or tower 63.5 ft. 

 On account of temporary service and liability to accident, 

 wooden trestles are now rarely used ; stone and brick masonry, 

 although formerly much employed, has recently, on account 

 of cost, been supplanted by metallic towers, principally of 

 steel. 



Possibly one of the best modern examples of the tendency 

 toward the erection of the elevated steel tower and tank is 

 that lately constructed at Jacksonville, Florida, at a cost of 

 $10,000, from designs by Superintendent R. M. Ellis, C.E., 

 1898. This tank is 30 by 45 ft., with conical bottom and 

 cover, surrounded by an ornamental balcony about its base. 

 The tank is supported by 10 6-in. " Z"-bar columns, 100 ft. 

 in height, stiffened with 8-in. " I "-beam ties, and the usual 

 diagonal tie-rods. The steel in the columns is specified 

 to have a tensile strength of 70,000 to 75,000 Ibs. ; elastic 

 limit 40,000 Ibs., with an elongation of 20 per cent, in 8-in., 

 and a reduction at fracture of 40 per cent. 



Steel for the tank, straps, rods, and rivets is to be of 

 60,000 Ibs. as a maximum and 56,000 Ibs. as a minimum ten- 

 sile strength ; 25 per cent, elongation in 8-in., and 50 per cent, 

 reduction at point of fracture. 



No chemical requirements have been made. The joints 

 are made by butt-strap, and the usual requirements for shop- 

 practice and field-work are insisted upon. 



On account of the importance of this structure and its close 

 likeness to the notable tank whose failure at Fairhaven, M,i 

 has given rise to much discussion, and hereinafter mentioned 



