METHODS OF SAMPLING AND TESTING HIGHWAY MATERIALS 47 
3. When sand bearings are used (figs. 17 and 18), the ends of each specimen 
of pipe shall be accurately marked prior to the test in quarters of the circum- 
ference. Specimens shall be carefully bedded, above and below, in sand, for 
Socket (beyond Bearing), 
darrefofpipe 
i rud. 
Loeoer Bearing 
'/If feast 6*6* 
L 
Side View 
Fig. 15. — Arrangement for three- 
edge bearing test of pipe, with- 
out bell and spigot 
H U 
,* L 
Fig. 16. — Arrangement for three- 
edge test of bell-and-spigol pipe 
one-fourth the circumference of the pipe measured on the middle line of the 
barrel. The depth of bedding above and below the pipe at the thinnest points 
shall be one-half the radius of the middle line of the barrel. 
