55 



freely horizontally. Back of this, and horizontal to it, a wooden shaft is 

 placed for regulating the tension of the wire, and still back of this is a 

 vertical spindle, from which wire unwinds automatically. The wire used 

 for reinforcing is a No. 12 gauge, galvanized wire, having a tensile strength 

 between 500 and 600 pounds. A coil of this is placed vertically upon the 

 spindle, the wire is passed around the tension shaft, thence into the screw 

 groove, and is finally firmly attached to one end of the pipe length by 

 soldering. The pipe is then revolved by two men at the crank handles, by 

 which process the wire is wound upon the pipe under a high tension, the 

 spacing of the laps of the wire being made even by the screw groove. 

 Variation in spacing for different heads is accomplished by using pulleys 

 of different diameters, to govern the rate of revolution of the grooved 

 shaft as compared with that of the pipe length. The reinforcing is stressed 

 the same as that in the main pipe. 



When the reinforcing reaches the end of the pipe length, the last two 

 or three laps being made parallel, it is again soldered, and the wire is 

 severed. A steel trowel curved to conform to the shape of the pipe, and 

 suspended above it, is then dropped into place, and then cement mortar 

 1%-1, is run upon the pipe as it revolves, the trowel smoothing this down 

 to a uniform thickness. The bulkheads are then undamped by a lever at 

 one side, the pipe is removed, and is carried away to be properly cured. 



"In the trench the bell and spigot ends of the pipe are fitted together, as 

 in the case of sewer pipe. Around the joint is placed a flexible form, made 

 of very heavy canvas, attached to blocks of wood, sawed out in such a way 

 that a space of about one inch measured transversely to the pipe, and six 

 inches longitudinally is left vacant for the reception of the mortar. Along 

 each edge of the form is run a 12-gauge wire, terminating at one end in an 

 iron ring, at the other in a tongue pin, curved in shape, so that when 

 clamped through the ring, it draws the wire to a high tension, firmly bind- 

 ing the form to the pipe. The form is then filled with cement mortar, and 

 immediately afterwards the interior of the joint is carefully pointed to in- 

 sure water tightness, independently of the collar, as far as practicable. As 

 soon as the collar forms can be removed, the trench is backfilled, to pro- 

 tect the collars while curing." Journal of Idaho Society of Engineers, 

 pp 40-41, Vol. No. 1. 



In southern California reinforced pipe built in the same manner has 

 been used. It is wound with No. 12 galvanized wire spaced about 1% 

 inches apart and coated over to protect the wire from corrosion. The cost 

 of reinforcing the hand tamped pipe is 10 cents per foot for 10 inch pipe, 

 15 cents for 12 inch pipe, 25 cents for 20 inch pipe, and 35 cents for 

 26 inch pipe. 



4. Cost of Making Reinforced Concrete Pipe. 



On the Umatilla project in Oregon, a number of reinforced concrete pipe 

 lines 46 and 30 inches in diameter and aggregating several miles in length, 

 have been installed and are entirely successful. These pipes were three 

 inches thick, made as described above. The cost of each is given below. 

 The concrete was composed of 1 part of cement to 2.3 parts of sand and 3 

 parts of gravel, screened through 1 inch mesh and rejected on *4 inch 

 screen. Cement cost $2.25 a barrel, sand $1.00 a cubic yard, gravel $2.65 

 a cubic yard. The steel spiral in place cost 5 y 2 cents per pound. 



