Telegraphic Pole Test,

Progress, Volume V, Issue 12, 1 October 1910, Page 25

Telegraphic Pole Test,

The recent test was conclusive that a pole six weeks old, based upon scientific principles, such as Mr. Bertinshaw's patent, is equal to the safe load required. In the past the Post and Telegraph Department, and. municipal bodies, have been quite satisfied with totara poles, as is clearly demonstrated in the City of Wellington. The following figures will be interesting to those who have doubts as to the lasting qualities of ferroconcrete. The pole tested was 100 square inches at the base, and 37 square inches at the top, and the crushing load was 2600 on the corapressional side; the total' length of pole was 36ft., and the length from ground to load was 26ft. 3in., therefore we have 26ft. 3in. x 2600 = 68,2501b5., or 30.5 tons to fracture the concrete at the ground line. This equals the compression on concrete on the compressional side of the pole equal to 19101bs. per square inch, or a total of 38,2001b5. total loads,' so that it was clear that by this patent system of reinforcement the strength developed to no less a total than 68,2501b5. To arrive at what the pole will carry in years to come the following figures have been computed from experimental tests on concrete, by reliable authorities in. London and elsewhere. 1. Results of experiments carried out for the London Post Office extension works, to ascertain the strength of concrete in compression: • Eeports dated 18th December, 1907, 25th April, 1908, 3rd May, 1909.