366 COST DATA 



sections, as steel reinforcement is bought by the pound. 

 Tables of these weights will be found on pages 253 to 265. 

 If such weights cannot be found in manufacturers' catalogs 

 or elsewhere, the following rule may be used: 



Multiply the sectional area of the steel in square inches by 

 its length in feet and by 3.4. The product will be the weight 

 of the steel in pounds. Usually it is not necessary to estimate 

 the quantity of steel used for stirrups, as 10% of the main 

 reinforcement is a close approximation. This 10% includes 

 such additional steel as would be used for column ties, 

 wiring, etc. It should be noted that the different sizes of 

 steel should be kept separate, as in most localities the price 

 of steel per pound increases as the size of the bar decreases. 



It is not necessary in estimating the volume of concrete 

 to deduct the volume taken up by the steel reinforcements. 

 After the volume of concrete has been obtained, the amount 

 of sand, cement, and broken stone can be estimated from 

 the table on page 244. The cost of mixing concrete is in the 

 neighborhood of 30 cents per cu. yd., using labor at $1.50 

 per da. In localities where the price is higher, this figure 

 must be increased. Machine-mixed concrete costs from 

 50 to 60% as much as hand-mixed concrete. 



The entire cost of mixing, wiring, and placing, including 

 foreman's wages, in a large eastern city amounted to $1.30 

 per cu. yd. However, this value must be determined for 

 every different locality having different scales of wages. 



Sand is usually bought by the ton, but measured by the 

 cubic yard. One long ton is equal to about 1 cu. yd. of dry 

 sand. The cost of steel reinforcement varies in different 

 localities, and no exact figures can be given. Usually, if 

 it is of the girder-frame type, a man can place in the forms 

 about 1,600 Ib. of reinforcement in a day. If it consists of 

 loose rods, one man can place from 800 to 1,200 Ib. per da. 



The cost of form work cannot be given in general terms. 

 The estimator must know the quality of forms to be made, 

 and measure up the approximate amount of wood required. 

 If possible, the forms should be used two or three times on 

 the same job, and they should have a certain selling price 

 after the work is completed. 



