420 Missouri Agricultural Report. 



to the breaking point and it will be seen that the lower part of the 

 beam has pulled apart, was in tension, while the upper part has 

 crushed together, or was in compression. Therefore, if a beam be re- 

 inforced, the reinforcement should be placed near the lower part of 

 the beam in order to take the tension, else the strength of the rein- 

 forcement is undeveloped. 



In placing the concrete, take espeCiq,l care not to displace the re- 

 inforcement from its true position and to wholly and solidly embed it 

 within the concrete. 



Costs — Cost items are entirely dependent upon the local prices of 

 material and labor. The cost of forms range from 20 to 40 per cent, 

 of the cost of the concrete. An approximate rule with which to 

 arrive at the amount of lumber necessary for forms is to multiply 

 the number of square feet of surface area of the structure to be 

 sheeted by 2.7; the product is the number of feet B. M. required for 

 sheeting the area 2 inches thick and the necessary studding to hold 

 it in place. The forms are erected and taken down for about $7.00 

 per 1,000 feet B. M. 



The cost of mixing and placing concrete by hand is about .$1.25 per 

 cubic yard. Where the quantity will justify the use of a machine 

 mixer, it can be done for about one-half to three-fourths of that 

 amount. 



With price of cement 40 cents per bag, sand and rock or gravel 

 each $1.50 per cubic yard, lumber $20.00 per 1,000 B. M., and labor 

 17i'2 cents per hour, the actual cost is about as follows for a 1-3-6 

 concrete : 



Cement 



Sand 



Stone 



Mixing and placing. 

 Lumber for forms . . 

 Erecting forms 



Total 



51.75 per cubic yard of concrete. 

 0.75 

 1.50 

 1.25 

 0.70 

 0.30 



$6.25 



This includes nothing for excavations, superintendency and inci- 

 dentals. 



Steel for reinforcement at $30.00 per ton is about $1.30 per cubic 

 yard of concrete. It costs about $7.00 per ton to place or 20 cents 

 per cubic yard of concrete, making an additional cost of $1.50 or 

 $7.75 per cubic yard of reinforced concrete. 



Other costs under varied conditions can be obtained from the 

 practical statements and examples in the last part of this bulletin. 



