PROJECTS IN CONCRETE CONSTRUCTION 



163 



trcme care must be observed in mixing, placing and 

 reinforcing to insure a strong water-tight construction. 

 Working Instructions: 



1) Like every other piece of concrete work, the water tank 

 must be constructed on a solid foundation. The soil 

 should be firmly tamped before the form is set in 

 place. In the preparation of the foundation, the 

 proper placing of the outlet and inlet pipes must be 

 given consideration, since both should be brought 

 thru the bottom of the tank. For a large tank, it is 

 well to excavate and form a sub-base of cinders or 

 gravel. 



2) The form for a circular tank is the most difficult part of 

 the tank to build. 



For ouf&rc/e 

 Sill 



of" fop 



However, by 

 carefully study- 

 ing the plan, one 

 should experi- 

 ence little 

 trouble. It will 

 be noted on plan 

 that both the in- 

 side and outside 



forms are made 



FIG. 154-a. Detail of sill for circular form, 

 in six sections. 



This makes the length of each section equal to one-half 

 the diameter of the tank. If the inside diameter of 

 the tank is to be 6', the outer length of section for in- 

 side form will be 3', less the thickness of boards used. 

 The inner length of outside section will be equal to one- 



