. Electric railway journal . nducted in Pittsburgh onJuly 30 and 31 by the Pittsburgh Reinforcing Pole Com-pany to determine the breakdown limits of poles which hadbeen equipped with its Orr reinforcing collar. In this Cracking of Reinforcement Under Excessive Loading system of prolonging the useful life of a wooden pole, acollar and sleeve of concrete reinforced with rods and ex-panded metal are applied at the ground line—the part whichis must subject to decay. The poles under test comprisedfive 40-ft. and ten 30-ft. chestnut and ten 30-ft. cedar poleswhich a certain company had reinforced se
. Electric railway journal . nducted in Pittsburgh onJuly 30 and 31 by the Pittsburgh Reinforcing Pole Com-pany to determine the breakdown limits of poles which hadbeen equipped with its Orr reinforcing collar. In this Cracking of Reinforcement Under Excessive Loading system of prolonging the useful life of a wooden pole, acollar and sleeve of concrete reinforced with rods and ex-panded metal are applied at the ground line—the part whichis must subject to decay. The poles under test comprisedfive 40-ft. and ten 30-ft. chestnut and ten 30-ft. cedar poleswhich a certain company had reinforced several months be-fore in accordance with the manufacturers specifications. When tested, the cedar poles broke off above the rein-forcing collar at an average pull of 2000 lb., and the chest-nuts at an average pull of 3000 lb. The load was applied 30ft. above ground on the 40-ft. poles and 19 ft. above groundon the 30-ft. poles. The ultimate strength of the reinforce-ment was satisfactory, but in nearly every case cracks de-. Reinforcement Surviving Breakage of Pole veloped in the concrete collars at 1500 lb. The customerexpressed the opinion, however, that a steel and concretereinforcement should be able to withstand a pull of 2000 $infi|lar conditions without developing cracks in theconcrete. The poles for the second test were therefore re-inforced to meet this requirement by substituting a heavierexpanded metal and by adding 1 in. to the thickness of theconcrete in the collars and sleeves. ELECTRIC RAILWAY JOURNAL
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