GATE STRUCTURES FOR IRRIGATION CANALS. 



35 



drop in the structure 2 feet. The side walls through the bank are 5 

 feet apart and 18 inches thick, carrying a bridge slab 6 inches thick 

 for a roadway 6 feet wide. This slab is reinforced the short way 

 with half-inch rods placed 6 inches on centers. Below the bridge 

 the lower wings, which are 6 inches thick, slope down from the bank- 

 crest height to 6 feet above the floor. 



The vertical sides of the water cushion are 10 feet high, 18 inches 

 thick, and flare at an angle of 30° with the axis of the ditch. Below 

 the cushion the lateral is lined for a distance of 10 feet with 6 inches 

 of concrete, the sides sloping up at | to 1 from a bottom width of 8 

 feet. The earth section below the lining shows signs of erosion for a 

 short distance, so it probably would have been better to construct the 

 water cushion about 5 feet longer or line the lateral 8 or 10 feet more. 



There is a 4-foot cut-off at the canal end of the structure and a 

 3-foot cut-off at the lower end. Each of these is 1 foot thick. The 

 gate proper is of sheet steel with a rack-and-pinion lift. 



This structure contains 111.7 cubic yards of concrete mixed in a 

 1 : 2^ : 5 proportion for plain and 1:2:4 proportion for reinforced 

 concrete. The material in the concrete cost $9 per yard and the 

 labor of concreting, excluding the excavation, was $2.29 per yard. 

 Form lumber, on a basis of using it four times, cost 57 cents per 

 yard. The excavation was in wet material, about one-half being 

 cemented gravel. Water and cement were hauled one mile. The 

 itemized cost is as follows : 



Itemized cost data for low line lateral headgate. 



Item. 



Time or quantity. 



Rate. 



Amount. 



Excavation: 







$17. 50 



Laborers 



276 hours 





69.00 



Team 







7.50 



Carpenters '. 







2.00 



Material: 



Cement 



133 barrels 



$2.10 per barrel 



279. 30 





5,000 feet b. m... 





27.50 



Sand 





84.80 per yard 



220. 80 



Gravel 





$6.70 per yard... 



402. 00 



Rock plums 







42.00 



Gravel i 







6.00 



Steel 







3.20 



Hauling 







25.00 



Concreting: 



Foreman 







32.00 



Laborers-. 







135. 00 



Carpenters 



160 hours 





64.00 



Helper 







24.75 











Concrete structure 



1,357.55 



Steel gate 







100. 00 











Total cost of structure 



1,457.55 











i Screening some old gcavel at site. 



