Essais sur poutres en béton simple et renforcé . -ifié en cas de matériaux ayant des coefficients d'élasticité constants tant en tension qu'en compression. Dans le cas du béton, il n'y a pas beaucoup d'informations relaibles qui regiflent son coefficient d'élasticité, mais comme il semble indiquer que le coefficient n'est pas constant butylvarie avec la contrainte. L'hypothèse en ce qui concerne une planésection dans de telles conditions laisse un élément de doute dans les déductions et, si possible, doit être supprimé, Tf-^stswere fait sur deux poutres pour déterminer la relation entre un plan
1343 x 1861 px | 22,7 x 31,5 cm | 9 x 12,4 inches | 150dpi
Informations supplémentaires:
Cette image appartient au domaine public, ce qui signifie que le droit d’auteur a expiré ou que le titulaire du droit d’auteur a renoncé à ses droits. Les frais facturés par Alamy couvrent l’accès à la copie haute résolution de l’image.
Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.
Tests on plain and reinforced concrete beams . -ified in case of materials which have constant coefficients ofelasticity both in tension and in compression. In the case ofconcrete there is not a great deal of relicible information re-garding its coefficient of elasticity, but such as there iswould seem to indicate that the coefficient is not constant butvaries with the stress. The assumption in regard to a planesection under such conditions leaves an element of doubt inthe deductions and this if possible should be removed, Tf-^stswere made on two beams to determine the relation between a planesectio::^ before and after deflection andthe ? results were ofmuch interest. It was anticipated that the beams might twist somewhat.Extencoraeter readings were accordingly taken on both sides butthe results indicated that there was little difference in thedata thus obtained and that either set could be used as corT^ect.It was then decided that both sets of extensometers could beplaced one one side to obtain the desired data in regard to the. 26. action on a plane section, and this was done with beams lJo.22and No. 27. The arrangement of the extensometer frames for thispurpose ir shown on plate No, 10 . The span over which the de-fomiations were taken was the same for laoth sets and all theupper coiitacts wer3 placed the same distance helow the top of the?beam; but the lower contacts for one set were eleven inches he-low the upper contacts while the vertical distance hetween thecontact :ioirits for the other set was lesr hein.- six inches forbeam No. 22 and n l/2 in. for beam No. 27. The results areshown on the plotted graphs for beams No. 22 and No, 27 and intable 26, The positions of the neutral axis as determined from eachof the two sets were practically the same for loads above 5000lb. It will be noticed that with each beam the values from oneset run greater by a small constant than the values from theother set. This fact would lead .is to surmise that such a diff-erence mip
