. Canadian engineer. oncrete in an up and downstream direction(due to the weight) thereby introducing additional initialaxial compression. The total resulting initial axial com- •Prof. C. von Bach has been kind enough to make sometests for the writer to determine m for concrete 1:2:3. Hefound for .specimens 45 days old, using- between o. i and 24kg. per sq. cm. compression, m to be See also und FestiRkeit, 5 Auflag-e Seite 301. Consideringthat large stone will be embedded in the concrete in mostdams the factor 5 has been used for ni as probably represent-ing- most closel
. Canadian engineer. oncrete in an up and downstream direction(due to the weight) thereby introducing additional initialaxial compression. The total resulting initial axial com- •Prof. C. von Bach has been kind enough to make sometests for the writer to determine m for concrete 1:2:3. Hefound for .specimens 45 days old, using- between o. i and 24kg. per sq. cm. compression, m to be See also und FestiRkeit, 5 Auflag-e Seite 301. Consideringthat large stone will be embedded in the concrete in mostdams the factor 5 has been used for ni as probably represent-ing- most closely actual condition =;. pression at the foundation of section shown in Fig. 3 istherefore (in terms of head of water): 1/5 (1-27 H + H) =: 0-454 H - (5) where Poissons ratio has been taken equal to 1/5.* The height of water, h, that this initial axial com-pression of o 454 H will resist without causing any shorten-ing of the length of the arch at the bottom can be foundby using (1), thus: h = 0-454 fi ^— - - - (6). /.roo,oooLhs. Fig. 3. For the narrower section, shown in Fig. 3, i = 70-feet at the base and i?a = 75 feet. Substituting thesevalues, it is seen that this section at the very bottom is able to carry h = 0454 x H x - = 0425 H, or 42-5 75per cent, of the total head of water as an arch before anyshortening in the length of the arch occurs. *Mr. H. Ballet was probably the first to point out thenecessity of taking Poissons ratio into consideration whciattemping to find the actual stresses in a dam body.—Proceed-ings of the Institute of Civil Engineers, igoc). Page 51. 3^0 THE CANADIAN ENGINEER Volume 30. The initial axial compression holds in equilibrium thestresses due to 42 5 per cent, of the total head at thebottom, the remaining 575 per cent, of the load willdivide between cantilever arch and curved beam action inproportion to their relative carrying capacity. By analyzing: (6) it is seen that by simply varying t orRa, or both, the designer can utilize more or le
Size: 1110px × 2250px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1890, bookidcanadianengineer30toro
