File:Stresses in the web reinforcement of restrained concrete beams (1917) (14781884624).jpg

Identifier: stressesinwebrei00lars (find matches)
Title: Stresses in the web reinforcement of restrained concrete beams
Year: 1917 (1910s)
Authors: Larson, Louis J
Subjects: Concrete beams Bending stresses Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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d a slightnegative slip indicating compression. This is verified by thestraiix gage readings on gage lines 13 which were at the end of theupper fears at the same point as the dials. Small tension cracks formed over both supports at 20 goo lb.load and at 33 300 lb. similar cracKs were found crossing gagelines 11 at all points except on the S, E. face. Up to a load of9S 000 lb. this beam acted in the same manner as one with web re-inforcement hut at this load a diagonal tension crach, formed andwas apparently opening up suddenly. The load reached 102 gOO lb.when the beam failed suddenly at south end. A view of this beamafter failure but before removal from the testing machine isshown on page 27 Pig. ^ . It will be noticed that diagonaltension cracK extended up to the longitudinal steel and then fol-lowed the bars splitting off the concrete above the bars out tothe load point. The diagonal cracks running down from the innerload points were also seen to be opening up somewhat at a load of
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9 ceo lb, out they never became dangerously large. 3EA? 3SO. 2This team was a duplicate of 380.1. There were some additional gage lines on the steel of toisbeam but 210 slip measurements were taken. Readings were alsotaken of the cleformations in the concrete web of this beam nearthe supports. Up to a load of 61 3?o lb. the behavior of this beam was sim-ilar to its mate. At this load, however, a diagonal tensioncrack formed at the s. E. extending from gage line 11a across attand h^ stepping Just short of «e». At SI SCOlb. diagonalcracks were visible across a toward »c» and Mdw on IT. E., andacross »a», »b», »c», »f», and «e» on S, v. On the s. E. thecrack noted at the previous load had extended across gage linee. During the application of load up to the maximum of 1C-1!- 000lb. nothing new developed. The old cracks extended and increasedin size until the beam failed suddenly at south end. Special care was take to observe any slipping of the bars inthe top of the beam but

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