. Tests of Rocky Mountain woods for telephone poles . culating the dry weight per cubic foot, a total shrink-age of 12 per cent for the fire-killed pine and spruce was assumed, and10 per cent for the cedar. The air-seasoned pine poles were con-sidered as being one-third below the fiber saturation point (that is,a 4 per cent shrinkage in volume was assumed as having already oc-curred), and the others were assumed as being half-way between thedry and the fiber-saturated states. RESULTS OF TESTS. CHARACTER OF FAILURES. Figure 6 shows the common types of failures occurring in the polestested. The
. Tests of Rocky Mountain woods for telephone poles . culating the dry weight per cubic foot, a total shrink-age of 12 per cent for the fire-killed pine and spruce was assumed, and10 per cent for the cedar. The air-seasoned pine poles were con-sidered as being one-third below the fiber saturation point (that is,a 4 per cent shrinkage in volume was assumed as having already oc-curred), and the others were assumed as being half-way between thedry and the fiber-saturated states. RESULTS OF TESTS. CHARACTER OF FAILURES. Figure 6 shows the common types of failures occurring in the polestested. The bend of the pole while under load was at a maximum nearthe center of the span for the first part of the test and about 2 feetnearer the load point at maximum load. This shifting at the point22740°—14 2 10 BULLETIN 67, U. S. DEPARTMENT OF AGRICULTURE. of greatest deflection was most noticeable in the poles having a ten-dency toward longitudinal shear. The effect of knots was in evi-dence only as localizing the compression wrinkles and occasionally.
Size: 876px × 2852px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherwashi, bookyear1914
