CONCRETE POLES

Hokitika Guardian, 17 February 1927, Page 4

CONCRETE POLES

ADVANTAGE OVER HARDWOOD. Aware of the success that has attended recent experiments in California in the manufacture of concrete posts, a number of prominent builders and contractors in Auckland have formed tne opinion that the day of the hardwood pole is nearly over. Mr R. Sanders, of Auckland, who recently returned from, a visit to America and the Continent, is a strong champion of the new article. "The concrete pole, as made by the centrifugal process, will compete successfully with the hardwood pole, as it is cheaper and will last for all time.” lie said in an interview

to-day. Poles manufactured by the centrifugal process are now being turned out by a huge firm in Los Angeles. Until recent months this firm concentrated on the manufacture of street lamp posts and were so successful that they have now supplied these articles throughout Los Angeles, San Diego, San Pedro, and Pasadena. The introduction of these reinforced concrete standards into the realm of street, park and boulevard lighting at first met with considerable opposition, through a general lack of appreciation of concrete and its possibilities, hut today concrete is almost universally accepted as the world’s most important structural material. fn their manufacture of lighting standards this American I firm used a granite concrete which not only possessed endurance and a sparkling appearance, hut also was heavily reinforced with steel rods. Lighting standards of this type were constructed in thousands, their beauty, utility strength and economy winning for them ( the preference of municipal authorities ( as well ns the approval of the general public. I

It is claimed for the centrifugal process of construction that from 15 to 35 per cent more material’is forced into a

given body of space than is now being done in concrete construction. The natural result of this forcing is the production of a post of greater density and strength than one made of a casting oi the same, exterior diameter. The whole process is a wet instead of a dry one, the proper hydration of the cement thus being assured. Fourteen years were spent in experiments before the centrifugal process was a success. Tbo huge pipe machines on which the lighting standards and poles are spun whirl the moulds around at 400 revolutions per minute. After ten minutes’ spinning the moulds arc removed, and within four hours tlie completed post or standard, artistically finished, according to the shape of the mould, is ready to be carted from the factory. Vlien Mr Sanders was in California in November last the manufacture of concrete telegraph posts by the centrifugal process, was only in an experimental stage. One UGft pole was sunk six feet in tbo ground and subjected to a strain of 15001 b and failed to show any signs of weakness. “ Yes, I believe that the concrete pole is bound to replaeo the hardwood article, which cannot stand the test of time,” concluded Mr Sanders.