File:The elastic properties of concrete under bi-axial loading (1912) (14781010582).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

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
stressed in twodirections may be found in buildings and other engineeringstructures, but the most coranon and probably the most importantexemple is the comparatively ne?/ type of construction foundin girderless floors. The flat plate of homogeneous materialdoes not readily lend itself to strict analysis. The analysisis even more difficult for a flat composite structure made oftwo materials such c.s concrete and steel. Confidence in thistype of construction has been established by continued successfuluse and by recent tests in which actual elongations of the fibershave been measured. The stresses in the steel are principallypure tension, therefore measured deformation can at once beexpressed as stress vrhen the modulus of elasticity is IcnoYm.The concrete is not under simple stress, but is subject toflexure in multiple directions; therefore the stress can notbe exactly stated from a Icnowledge of the relation betvreenstress and deformation obtained from a test in simple compression. 11
Text Appearing After Image:
12 The present practice in the design of structure^ is lar(;elyempirical. The structure is designed to resist stresses foijindfrom bending moment formulas 7/hich are based on uncertainanalyses or on so-called tests. The ordinary vrorhing stressesin the materials have been used. The designs have been quitegenerally satisfactory but the limit of economy of the flatslab system of construction has not been established. T/e must loolc to the results of tests of actual structures todetermine where the stresses are greatest, v/here the designsshould be strengthened and v/here they may be cut dorrn. Deformations can be measured but they mean very little tothe designer until they have been expressed in terms of stress.Consequently it is desirable to establish an exact relationbet^reen stresses and deformations of concrete bi-axially loadedand to find the similarity or difference betTireen the stress-deformation relation thus found and the relation under simpleloading. Present practice assumes

Note About Images