An investigation of hooped concrete columns . made it almost impossibleto make straight columns of uniform diameter. This trouble couldhave been obviated by using three spacing bars, as is, oftendone. Auxiliary Three 6-in. cubes and onecylinder 8-in. x 16-in. were made from each batch of concretein order to determine the strength and modulus of elasticityof the concrete used. The auxiliary specimens for the 30-ft. col-umns were made from the two batches after they had been all cases these specimens were made after the forms had beenfilled about half full, with the idea of
An investigation of hooped concrete columns . made it almost impossibleto make straight columns of uniform diameter. This trouble couldhave been obviated by using three spacing bars, as is, oftendone. Auxiliary Three 6-in. cubes and onecylinder 8-in. x 16-in. were made from each batch of concretein order to determine the strength and modulus of elasticityof the concrete used. The auxiliary specimens for the 30-ft. col-umns were made from the two batches after they had been all cases these specimens were made after the forms had beenfilled about half full, with the idea of securing results thatwere as near the average of the whole batch as possible. Extensometer readings were taken on the cylindersand the ultimate loads determined for the cubes. The load -deformation curves for the cylinders are plotted on pages 44to 47 . The numbers are the same as those of the columns towhich the cylinders belong. The ultimate strengths of the cylin-ders and cubes and the ages at which they were tested are givenin table 11 3. The forms were made of 2 l/2-ft. sectionsof sheet iron clamped to the spirals by means of iron strapsfastened with tolts. It was found that with these sectionalforms it was almost impossible to secure straight columns, thetwo spacing bars on the spirals allowing the spiral to bendtoo readily. Heretofore no such difficulty had teen found withspirals having three spacing bars. While there was not muchtrouble with the 5-ft. columns, even these were not always asstraight as was desired. With the 10-ft. and especially with the20-ft. columns, it was only by a great deal of labor that evenapproximately straight columns we^e secured. For the the forms were put together around the spirals whilelying on the floor after they had been straightened out as muchas possible. The forms were then rolled on to a ladder and lift-ed into place by means of a hoist. It was necessary to useseveral braces to hold them straight after rais
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttheses, bookyear1914
