lateral to vertical pressure ratio for concrete slurry-which value to?
lateral to vertical pressure ratio for concrete slurry-which value to?
(OP)
Hello guys,
Could anybody please tell me which lateral to vertical pressure ratio for concrete slurry do you use to calculate the lateral pressure during pouring the concrete slurry? If you take it as water, it will be 1.0, if you simulate it as earth pressure at rest, it will be 0.5. So which value you guys use in practice? Appreciate for your response.
Could anybody please tell me which lateral to vertical pressure ratio for concrete slurry do you use to calculate the lateral pressure during pouring the concrete slurry? If you take it as water, it will be 1.0, if you simulate it as earth pressure at rest, it will be 0.5. So which value you guys use in practice? Appreciate for your response.






RE: lateral to vertical pressure ratio for concrete slurry-which value to?
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
Manual de la Construcción de Hormigón
Tercera Edición Inglesa
Waddell, Dobrowski
McGraw Hill
México 1996
"for wall formwork with a rate of pouring less than 7 ft/h
p=150+9000xR/T
over 7 ft/h rate
p=160+43400/T+2800xR/T
R ratio of pouring of concrete ft/h
T temperature of the formwork, Farenheit degrees
p is the lateral pressure exerted on the formwork in psf"
from this only 500 issued books' mexican edition
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
Hmm, I need be more precise, for it also gives a parentheses after each of the cases above, explaining that
"2000 psf or 150h, the lesser" for both cases. So whilst I look a precise statement in the Manual of Concrete Practice I would assume you apply the formula for the rate, then you apply the formula for the height and pressure is growing from above to a maximum of that given by the formula or 2000 psf, the lesser of the two, a depth under which the lateral pressure would be constant at the maximum value.
It also gives a formula for pouring concrete in columns
p=150+9000xR/T where the parentheses note 3000 psf or 150h
hence it seems it grows with depth till it meets either 3000 psf or the value given at the formula, under which would remain constant.
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
Appropriate and monitored pour rates are vital to ensure satisfactory form performance when using the rates. If the rate will be difficult to follow or if the rate is expected to be ignored, designing for full hydrostatic pressure is appropriate, though the cost will be prohibitive.
The concept that an infinitely tall column of concrete will reach a maximum pressure and even out without respect to a pour rate is confusing to me. While ACI 347 provides minimum design pressures to be considered, I not aware of any basis to say lateral concrete pressures over 3000psf need not be expected. If the book recommends not trying to come up with a pour rate and placing scenario that would exceed 3000psf for reasons of common materials and constructability, that makes sense, but it is entirely possible to create form pressures above 3000psf and as such, the appropriate pressure must be designed for.
I would suggest purchasing the documents issued by committee 347, 347-04 Guide to Formwork for Concrete or Special Publication SP-4, Formwork for Concrete for complete information and appropriate context for the information previously given.
Metric pressure equations are available in the documents as well.
Hope it helps,
Daniel Toon
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
RE: lateral to vertical pressure ratio for concrete slurry-which value to?
Slurries do not typically need vibration to consolidate, so vibration loads need not be considered. Besides, the more liquid the material is, the less it will support shear transmission, thus negating vibration effects.