the tank additional stability when the tank is full. When the tank is empty the external 

 pressure may reverse the stresses in the wall. In every case, therefore, two sheets of rein- 

 forcement should be used, oneplaced near the outer surface and the other near the inner one. 

 The size of mesh near each surface may be of half the weight of the size called for in the 

 tables; for example, if 3-6-40 is required, two sheets of 3-9-20 placed as stated above 

 should be used. This rule will apply only for tanks up to 20 feet internal diameter. For 

 tanks of greater internal diameter, the design is somewhat complicated, and it is recom- 

 mended that the reinforcement called for in the tables should be placed near one surface 

 and a like amount near the other surface of the wall. 



How to In table 3 the size of mesh required to reinforce the walls of a square tank is 



Design a given. Table 4 gives the thickness of the concrete walls. The arrangement and location 

 Square of the reinforcement in the wall is shown in Figure39, which shows the details of a tank 



Tank. 10 feet square and 10 feet deep, designed with the data contained in tables 3 and 4. The 



data given in table 3 is an abbreviated form of designating the " Steelcrete " meshes as 



explained on page 108. 



Details. The floor of the tank should be monolithic with the walls and reinforced with 



" Steelcrete " 3-13-075 bent up into the side walls as shown. The thickness of the base 

 should not be less than 4 inches, and need not be over 6 inches, governed by the thick- 

 ness of the side walls. 



The corners should be filleted as shown. Square inside corners are an element of 

 weakness in reinforced concrete tanks. The extra cost of the form work required by the 

 method shown will be amply repaid by the additional stability attained. 



The ends of sheets should be lapped eight inches (one diamond) o more. The re- 

 inforcement should be continuous around the outer face. 



113 



