USES OF FERRO-CONCRETE.

New Zealand Herald, Volume XLVIII, Issue 14809, 12 October 1911, Page 8

USES OF FERRO-CONCRETE.

NEW TELEGRAPH POLES, j OYER A THOUSAND READY Wooden telegraph poles will soon bo lifSfc i thing •of the , past in New Zealand. I»>? - I the future they will give place'..to th# '? more durable poles made of ferro concrete. : I These poles, being uniform in design, will , '' j present a : more pleasing appearance to th# eye than do he woodten poles, which ar*' p: ! rough-looking and decidedly disfiguring " to the streets in which they are placed, 5 In every respect the Department ha*- f : found that the concrete poles are superior to wood or iron poles. • :41811 The contract for the making of thfl ' ferro-concrete poles is being carried out 1 - I at Freeman's Bay by the New Zealand Ferro-concrete Structural Engineering Company. Poles to the number of 1265 are already completed for the metallic ; circuit between Auckland and Hamilton, i ' f and the work of erecting the poles wiQVt' shortly be commenced. ; . Exhaustive tests have been carried oufcifi- t for the Department, and the strength - ofi - the poles is calculated to be sufficient to carry any lines that are required. Angle " poles, which are subjected to great stress, | have been found to be very serviceable b I the ferro-concrete material. „ yvffgiPjP For ordinary straight lines the poles 'SSI* I 6m by Bin at the base, and 6in by. 6in ; aPP I the top, the length being 26ft. The angle 1 poles are, however, much stronger. These 1 are llin by Sin at the base, Bin" by 4in st & the top, and 30ft long. The extra strength is required on account of the poles having to ■. carry a greater load. In ■ order |to reduce the weight these poles are : made hollow. . - For over a year past the company ha* been carrying _ out experiments for Sthafltf \ Department, with the object of making atfeS § concrete pole that would be much lighter vfei 1 than those made from the ordinary ferro. ' concrete. . The experiments have beenS® most successful. By a chemical process poles can now be made which are very' little heavier than totara. Teats recently 1 ■ made with an 18ft pole showed that they Si I could carry a greater load than either v ' wood or iron. Although the hollow in thelS 1 ferro concrete poles materially reduced the weight, they were not nearly so light as %■ the poles made with the new' material. Jfe is probable that poles made from this lewiiPi chemically-treated Concrete will r >'iSb9"|4||| largely utilised in future. The : average I life of a wooden or iron pole is set down I at about nine years, while it is considered that the ferro-concrete poles and those 1 chemically treated are practically everlasting. / ' "• |