METHODS OF SAMPLING AXD TESTIXG HIGHWAY MATERIALS 
99 
7. All These results shall be expressed in percentage of the original weight 
of the block and also in pounds per cubic foot. 
64. METHOD OF TEST AND INSPECTION OF CORRUGATED 
METAL CULVERT 
1. Corrugated metal culvert shall be subject to inspection at the factory, 
trench, or other point of delivery by the engineer or his authorized rep- 
resentative. 
2. The inspector shall determine the gauge of the metal, inside diameter, 
depth and spacing of the corrugations, width of lap, rivet spacing, weight per 
3"*4 *8 BLOCK 
4"x4"x8"BL0CK 
Fig. 43. — Method of boring wood blocks for sample. Borings made in end grain 
with %-inch bit or drill. Thi^e borings on center line made halfway through 
block ; other borings through block 
linear foot of the finished pipe, condition of spelter coating and other require- 
ments as failed for under the specifications. He shall also take a sample of the 
pipe material approximately 6 inches wide, and the full diameter of the pipe 
for measurement, chemical analysis, and determination of the amount of 
galvanizing or spelter coating. 
3. Chemical analysis will be made of all metal culvert pipe, including rivets 
to determine whether the requirements of the specifications as to quality of the 
material are met. 
