54 



after the pipe has been moulded and the pipe is left standing on the base 

 ring for eight days. 



For the 30 inch reinforced pipe the forms used are 4 feet long and 

 made of lumber lined with sheet steel (Figs. 42, 43). The interior core 

 consists of two main parts and a wedge or closing piece. The outside form 

 is made of four parts bolted together. 



The reinforcement is made of wire wound into spirals 4 feet long by 

 means of a reel on which are hinged spacing bars with notches which give 

 the wire the proper spacing. (Fig. 44). After the wire is wound, longi- 

 tudinal rods 4 feet long are placed on the outside of the spiral and con- 

 nected to it by bending the ends over the wires of the spiral at the two 

 ends and by tying them together with wires. The spiral can then be re- 

 moved from the'reerby turning down the hinged spacing bars, and is made 

 more rigid by cross lacing with wire. 



2. Method of Joining. 



The pipes, after they have hardened sufficiently, are placed in the trench 

 where they are joined. The best time to lay the pipe is in cold weather, for 

 a rise in temperature will produce expansion and make the joints tighter, 

 while if they are laid in the summer time, any contraction due to lowering 

 of the temperature will tend to produce shrinkage cracks. The joints may 

 be made in three ways: (1) bell and spigot, (2) collar joint, and (3) 

 lock joint. 



Bell and spigot joint. 



The bell and spigot joint has been used on smaller pipes where the pres- 

 sure is not great. On the Umatilla project some of the 30 inch pipe has 

 been laid under a pressure head of 23 feet with this type of joint. The 

 pipes are similar to the non-reinforced pipe previously described and have 

 a taper end and a bell nd, the joints being made in the same manner as 

 the joints for non-reinforeed pipe. 



Collar joint. 



This joint is used for larger pipes and greater pressures. The joint is 

 made with a reinforced collar from 4 to 8 inches wide, whose inside diam- 

 eter is slightly larger than the outside of the pipe. The collar, which has 

 been slipped over the pipe last laid, is placed over the joint and the space 

 between the interior of the collar and the outside of the pipe is filled with 

 a rich cement grout poured through two holes in the collar and prevented 

 from running out by means of a mortar paste spread around the edges of 

 the collar. 

 Lock joint. 



The lock joint is intended to make the longitudinal reinforcement con- 

 tinuous. It is used by the Reinforced Concrete Pipe Company and the 

 Lock Joint Pipe Company. 



3. Method of Making and Laying Reinforced Concrete Pipe on Roswell 

 Project, Idaho. 



On this project the reinforced pipe was made with the dry mixture hand 

 tamped pipe around which was wound the reinforcing steel wire which was 

 covered with a rich cement mortar. The method of winding the wire, 

 applying the plaster and laying the pipe is described as follows by Zenas 

 N. Vaughan, the engineer in charge: 



"Two movable bulkheads, with crank-handles attached, are so arranged 

 that the pipe length can be firmly clamped between them. At a distance 

 back of this device a steel shaft, into which is cut a screw groove, works 



