File:The elastic properties of concrete under bi-axial loading (1912) (14778368181).jpg

Identifier: elasticpropertie00mill (find matches)
Title: The elastic properties of concrete under bi-axial loading
Year: 1912 (1910s)
Authors: Millard, Floyd Hays
Subjects: Concrete Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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, three compressionspecimens .vere loaded on one arm and the same measurements ofdeformation made as were made in the other two cases. The horizontal load was applied with the jack and the verticalload with the testing machine. Ordinarily two men applied load,one with the testirog machine, the other with the pump. Theobserver running the testing machine called out each 5000-lb.increment of load (73 lb, per sq.in. increment of stress) andthe observer at the pump Icept the jack load as close to the otheras possible. The sloY/est speed of the testing machine (0,05-in.per minute) was employed. It was not hard to keep the loadswithin 2000 or 3000-lb, of each other. After the load wasapplied, the motor on the testing machine was stopped and a waitof two or three minutes followed, during which time the stresscoriditions in the specimen could adjust themselves somewhat tothe new loading. The loads used in computing the data were readjust before the first deformation observations were made and
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53 just after the set of observations was complete. The load on the faces of the 3-ln. cubes v/as increased inthe manner described in the previous paragraph. T^/hen one observerapplied both loads as was the case in some of the tests, anincrement of 5000-lb. was applied in the horizontal directionand the load in the vertical direction brouGht up to it, then2500-lb. more added in the vertical direction, followed by5000-lb. in the horizontal direction then 5000-lb. in the verticaldirection, then another 5000-lb. in the horizontal direction,and finally by 2500-lb. in the vertical direction malcing theloads equal. The arraiigement of the loadinr^ apparatus for the crossedbeans is taken up in 8. Description of Apparatus, The loadwas very slowly applied in increments of 15000-lb. betweenseries of observations. The pointer on the dynamometer couldbe quite accurately read and it was found easy to stop at anydesired load. Failure could be predicted by a baclcward motionof the dynamometer needle

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