60 
BULLETIN 126, U. S. DEPARTMENT OF AGRICULTURE. 
T 
i «n 
coated with asphalt before being inserted it may prevent leaks. The 
device likewise secures a fairly good bond. 
(I) A pliable metal sheet protected from rust, of the form shown in 
figure 3, d, has also been used for such purposes. When section A is 
being laid the metal assumes the form of a right angle, the vertical 
part being placed against the form. Before section B is laid the 
upper portion of the vertical is bent down to a horizontal position, as 
shown. 
(5); In the Bidenbaugh Canal of the Nampa and Meridian irrigation 
district, Idaho, tar paper was inserted between the abutting joints, 
which are spaced 16 feet 3 inches apart, and a good bond between the 
sections was secured by short ^-inch steel rods (fig. 3, e). 
(6) To overcome the objection of projecting rods in laying by the 
method just described, the plan of bonding shown in figure 3,f, has 
been devised. A socket is formed in sec- 
tion A by means of a short J-inch pipe, 
and into this is inserted one end of a steel 
rod five-sixteenths inch in diameter and 
double the length of a pipe. This con- 
trivance adapts the joint to the alternate 
method of laying, as illustrated in fig- 
ure 3, a. 
(7) The form of joint used by the writer 
on the Snake B a vine retaining walls of the 
Turlock irrigation district of California is 
shown in figure 3, g. In laying the fining 
in alternate sections the joint with its con- 
cave surface may be coated with hot asphalt or fined with tar paper 
before the adjacent section is laid. 
(8) In fining the Davis and Weber Counties Canal in Utah, a thin 
strip of wood coated with asphalt was placed in each joint and ex- 
tended through about two-thirds the thickness of the lining. The 
specifications called for the withdrawal of these strips and the filling 
hi of the spaces with hot asphalt, but this was not done. As a result, 
many of the wooden strips became loose and project more or less 
above the surface of the lining, thus retarding the flow of water. In 
other respects the joint has proved satisfactory. (See fig. 3, h.) 
(9) A somewhat similar joint (fig. 5) was used by the engineers 
of the Batterson Land & Water Co. and the East Contra Costa 
Irrigation Co. On both canals, to which references are made else- 
where, the wooden strips were removed and the spaces filled with 
hot asphalt to within three-eighths inch of the surface, the re- 
maining space being filled with cement mortar. When inspected 
by the writer during construction he questioned the advisability of 
so wide a joint, and was advised that a smaller joint could not well 
be filled with asphalt. 
Asphalt urS/gt \ Mortar. 
V.ft. &iij 
, A' 4J. ;$ £.1± , 
li 
Fig. 5. — Sketch of joint used for 
concrete lining, Patterson Land 
& Water Co., Patterson, Cal. 
