280 TOWERS AND TANKS FOR WATER-WORKS. 



Angles and other shapes, intended to form such a super- 1 - 

 structure as a tower, are usually sheared, milled, and con- 

 nected by riveting at a well-equipped bridge-works. The 

 same precautions as to riveting and cleaning should be taken 

 as with the tank work, and surfaces in contact and thereafter 

 inaccessible should be given at least two coat^ of red lead 

 and oil. Only connections should be made in the field, all 

 other parts being riveted in the shop before shipment. 



Preparation of Foundations. To avoid what is known as 

 " green masonry," as far in advance as possible before " field- 

 work," the foundation masonry should be laid. The site of 

 the structure having been determined, careful tests should 

 be made to determine the character of the soil and to ascer- 

 tain its bearing value. Such tests may be made by driving 

 test-pits with such an implement as a post-hole digger, or 

 by borings made with an auger of not less than 2-inch diame- 

 ter. The auger-bit is welded into a short section of pipe; 

 another short section is fitted with a cross-piece or handle, 

 and additional sections, having suitable couplings, are to be 

 prepared in sufficient number to permit the borings to be 

 carried to a safe and satisfactory depth. As soon as expedi- 

 ent after such borings, and the design of a foundation to sup- 

 port the structure, excavations are made and the subfounda- 

 tion or bearing prepared. The character of the connections 

 for the anchorage having been designed, flat planks or 

 boards should be connected in such a way as to form a suit- 

 able templet, which should be carefully laid off and holes of 

 proper size bored. The anchor-rods having been provided, 

 these are usually enclosed in old boiler or other tubes, 

 slightly larger than the anchor-rods, and of approximately 

 the same length or a little shorter. 



The rods and tubes are inserted into the holes of the 

 templet, which is then raised to the correct height or levd 

 and made fast with wooden props or stays. Each of the 



