An investigation of hooped concrete columns . f 1-2-4 concrete we findthat Poissons ratio varies with the per cent reinforcement,being smallest for the largest per cent. For the two largestper cents we find that the value denoted byjU/ie very nearlya constant. Considering curves (8), page30C, we find that forp = # the average value of i,is , for p = $ I = for p = .9?Ja, = Dividing each of these by the cor- responding per cent of spiral we get 1,87, , and Thatis for the two highest per cents of reinforcement the value ofPoissons ratio varies inversely about a3 the pe
An investigation of hooped concrete columns . f 1-2-4 concrete we findthat Poissons ratio varies with the per cent reinforcement,being smallest for the largest per cent. For the two largestper cents we find that the value denoted byjU/ie very nearlya constant. Considering curves (8), page30C, we find that forp = # the average value of i,is , for p = $ I = for p = .9?Ja, = Dividing each of these by the cor- responding per cent of spiral we get 1,87, , and Thatis for the two highest per cents of reinforcement the value ofPoissons ratio varies inversely about a3 the per cent of means that for a given longitudinal deformation the totallateral pressure is constant- and independent cf the per centof spiral. It is probable that the reason this is not true forthe columns having small per cents of spiral is that at theload at which the stress in the spiral reaches this valuethe concrete still has enough strength to carry part of the is possible that the above relation is true for the columns. 34 having .9$ spiral for very high lateral stresses. The following facts are found to be true for the5-ft. columns. To produce a stress in the spiral of 30,000 lb. persq. in. requires a load $ higher where p ? $ and 28. fi^higher where p = ™than when p = $. For a stress in thespiral of 50,000 lb. per sq. in. the increase in load is $for p = $ over that required for p = $. To produce a stress in the spiral of 56,000 lb. persq. in., the longitudinal unit deformation mu3t be increased40$ for p = $ and 89$ for p = $ over that required wherep = $. Considering the 5-ft. columns where p = $ we seethat the value of the longitudinal unit deformation at values offa of 40,000 and 50,000 lb. per sq. in. varies inversely as thevariation in the ratio of the volume of cement to the columnof aggregate. That is;to produce a stress of 50/000 lb. persq. in. in the spiral of a 1-3-6 column requires three timesthe defor
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttheses, bookyear1914
