English translation: isostatic/primary effect of shrinkage
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French to English translations [PRO] Tech/Engineering - Construction / Civil Engineering / bridge design UK English
French term or phrase:retrait isostatique
This is used in connection with the shrinkage of a concrete deck slab. I have been told that I can translate it as "primary shrinkage", but should appreciate confirmation or otherwise from person(s) with a knowledge of engineering.
Explanation: With regard to bridges, isostatic, or statically determinate, refers to bridges with spans which end at each pier or abutment, i.e. the bridge consists of a number of separate and independent, simply supported slabs or beams spanning between two piers.
A hyperstatic or statically indeterminate bridge OTOH is one with continuous slabs or beams, i.e. a slab or beam will be continuous over one or more intermediary piers. All of which induces different forces.
What do they actually say about this retrait isostatique? I can only imagine that somehow they are talking about shrinkage induced by and occurring within an individual span (shrinkage in isostatic spans?) as opposed to shrinkage related to the multi-span section of deck. Not that I can see how this can be done ...
-------------------------------------------------- Note added at 2 hrs (2009-11-08 15:55:21 GMT) --------------------------------------------------
Ah, yes, you overlook (for design calculation purposes only, not in real life) the (or part of the) forces at play in the isostatic section so that these forces build up cumulatively somewhere else.
You might find this helpful:
Look on page 28 (and elsewhere too might be helpful) here:
where the effects of shrinkage are given as:
1 + 2 isostatic (or primary) effects
and
3 – hyperstatic (or secondary) effects.
If you look at page 29, there's a diagram showing (as I understand it) how isostatic (in-span) effects (cracking) are overlooked to examine the hyperstatic effects (cracking in the middle of the two span bridge). So "isostatic" refers to a particular "in-span" section of deck, the effects of those isostatic forces, if overlooked, causing effects (cracking) elsewhere in the hyperstatic beam.
Personally I'd stick to "isostatic" since it immediately places you in the isostatic span ...
-------------------------------------------------- Note added at 3 hrs (2009-11-08 16:03:20 GMT) --------------------------------------------------
And it should be "isostatic EFFECTS of shrinkage", not "isostatic shrinkage".
File Format: PDF/Adobe Acrobat
two-girder bridge. Part III repeats the same operating and environmental ...... the action of the ISOSTATIC EFFECTS OF SHRINKAGE, and the ISOSTATIC EFFECTS ... www.setra.developpement-durable.gouv.fr/.../US_0720A_Calcul...
Although the bending moment is equal to zero in the cross-sections at the deck ends, the corresponding tensile stresses are not because their values include the self-balancing stresses due to the shrinkage (called “PRIMARY EFFECTS” or “ISOSTATIC EFFECTS” in EN 1994-2).
[ ... ]
During the second step of the global analysis, the cracked zones modify the introduction of the concrete shrinkage in the numerical model.
In fact the ISOSTATIC (OR “PRIMARY”) EFFECT OF SHRINKAGE (Nb = Ecm.εcs.Ab which is applied to the center of gravity of the concrete slab) is no longer applied in the cross-sections located in the cracked zones around internal supports (EN 1994-2, 5.4.2.2 (8)).
The « HYPERSTATIC » OR « SECONDARY » EFFECT OF SHRINKAGE is finally considered as the difference between the internal forces and moments calculated in the continuous girder by the elastic linear analysis under the action of the ISOSTATIC EFFECTS OF SHRINKAGE, and the ISOSTATIC EFFECTS THEMSELVES (see Figure 2-29). http://www.argenco.ulg.ac.be/pdf/SE/COMBRI Design Manual Par...
Then the meaning is clear: "retrait iso" means a shrinkage that can take place freely without causing any stresses, and "retrait hyper" means that the shrinkage movements are restrained and that stresses will occur that must be considered in the design.
The shrinkage of concrete is time-dependent. Some of it occurs when the concrete is very young, but the final shrinkage is not attained until after about one year.
The text I am working on is not that transparent. However, the program does work for the design of composite bridges where the slab segments are either pre-cast or cast on falsework. I think that I might have to ask the Client for more detail about what is referred to here. In addition to "retrait iso" and "retrait hyper" there is also short-term and long-term shrinkage. It is not at all clear how these all relate to each other.
If you cannot produce more context, one has to assume that "retrait isostatique" is a shrinkage that can take place without causing any extra stresses in the concrete structure itself or in the adjacent structural element. If that is the case, it would normally be called "free shrinkage".
In the light of the contributions from Kashew and Bourth, both referring to the mechanics of a finished structure, can you determine from the source text whether 'retrait isostatique' refers to shrinkage that occurs in the freshly-poured concrete (which has been my assumption so far...) or to the mechanics of the finished structure (as per assumptions made by our colleagues)?
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Answers
56 mins confidence:
isostatic contraction
Explanation: Isostatic means homogeneous, and retrait means contraction, I feel fairly sure.
konungursvia Canada Local time: 23:37 Does not meet criteria Native speaker of: English
Notes to answerer
Asker: Thanks for your suggestion; however, I really need answers based on a knowledge of the subject matter (engineering) rather than equivalents for individual words based on standard dictionary definitions.
Explanation: In as much as primary shrinkage is very likely to be isostatic (because it occurs in the material while is still in a fluid state), I see no reason not to follow the client's preference.
What causes excessive shrinkage - [ Traducir esta página ]There are two forms of shrinkage: primary shrinkage and secondary shrinkage. ... This primary shrinkage can be observed after the casting has cooled and ... www.ptm-w.com/index.asp?pgid=93 - En caché - Similares
[PDF] Page 1 EFFECTIVE SOLIDIFICATION MODELING 6-1 ... - [ Traducir esta página ]Formato de archivo: PDF/Adobe Acrobat - Vista rápida
of shrinkage porosity: Primary Shrinkage and Secondary Shrinkage. Primary Shrinkage. Primary shrinkage is due to the liquid contraction of the alloy during ...
outgoing.finitesolutions.com/SOLIDCastWorkbook/Unit%206.pdf - Similares
An investigation of the shrinkage behavior of oriented PVC in a ... - [ Traducir esta página ]were found to undergo two modes of shrinkage. Primary shrinkage, which corre- ..... observable shrinkage, primary shrinkage was completed. ...
doi.wiley.com/10.1002/adv.1990.060100203 - Similares
Shrink tunnel and methods relating thereto - Patent 5740659 - [ Traducir esta página ]Before the primary shrink step and preferably between the preliminary and primary shrink steps discussed above, a pair of side nozzles are preferably also ... www.freepatentsonline.com/5740659.html - Similares
de JF Cox - 1998 - Citado por 2 - Artículos relacionados - Las 2 versiones
xxxmediamatrix Local time: 01:37 Does not meet criteria Native speaker of: English PRO pts in category: 165
Notes to answerer
Asker: Thanks mm. I nearly went with your answer, but Bourth's discussion of why to include "effects" was persuasive.
Where t, is the age of concrete at the beginning of shrinkage. In both isostatic and hyperstatic beams, the analysis may be performed by superimposing the ...
kashew France Local time: 05:37 Meets criteria Specializes in field Native speaker of: English PRO pts in category: 314
Explanation: With regard to bridges, isostatic, or statically determinate, refers to bridges with spans which end at each pier or abutment, i.e. the bridge consists of a number of separate and independent, simply supported slabs or beams spanning between two piers.
A hyperstatic or statically indeterminate bridge OTOH is one with continuous slabs or beams, i.e. a slab or beam will be continuous over one or more intermediary piers. All of which induces different forces.
What do they actually say about this retrait isostatique? I can only imagine that somehow they are talking about shrinkage induced by and occurring within an individual span (shrinkage in isostatic spans?) as opposed to shrinkage related to the multi-span section of deck. Not that I can see how this can be done ...
-------------------------------------------------- Note added at 2 hrs (2009-11-08 15:55:21 GMT) --------------------------------------------------
Ah, yes, you overlook (for design calculation purposes only, not in real life) the (or part of the) forces at play in the isostatic section so that these forces build up cumulatively somewhere else.
You might find this helpful:
Look on page 28 (and elsewhere too might be helpful) here:
where the effects of shrinkage are given as:
1 + 2 isostatic (or primary) effects
and
3 – hyperstatic (or secondary) effects.
If you look at page 29, there's a diagram showing (as I understand it) how isostatic (in-span) effects (cracking) are overlooked to examine the hyperstatic effects (cracking in the middle of the two span bridge). So "isostatic" refers to a particular "in-span" section of deck, the effects of those isostatic forces, if overlooked, causing effects (cracking) elsewhere in the hyperstatic beam.
Personally I'd stick to "isostatic" since it immediately places you in the isostatic span ...
-------------------------------------------------- Note added at 3 hrs (2009-11-08 16:03:20 GMT) --------------------------------------------------
And it should be "isostatic EFFECTS of shrinkage", not "isostatic shrinkage".
File Format: PDF/Adobe Acrobat
two-girder bridge. Part III repeats the same operating and environmental ...... the action of the ISOSTATIC EFFECTS OF SHRINKAGE, and the ISOSTATIC EFFECTS ... www.setra.developpement-durable.gouv.fr/.../US_0720A_Calcul...
Although the bending moment is equal to zero in the cross-sections at the deck ends, the corresponding tensile stresses are not because their values include the self-balancing stresses due to the shrinkage (called “PRIMARY EFFECTS” or “ISOSTATIC EFFECTS” in EN 1994-2).
[ ... ]
During the second step of the global analysis, the cracked zones modify the introduction of the concrete shrinkage in the numerical model.
In fact the ISOSTATIC (OR “PRIMARY”) EFFECT OF SHRINKAGE (Nb = Ecm.εcs.Ab which is applied to the center of gravity of the concrete slab) is no longer applied in the cross-sections located in the cracked zones around internal supports (EN 1994-2, 5.4.2.2 (8)).
The « HYPERSTATIC » OR « SECONDARY » EFFECT OF SHRINKAGE is finally considered as the difference between the internal forces and moments calculated in the continuous girder by the elastic linear analysis under the action of the ISOSTATIC EFFECTS OF SHRINKAGE, and the ISOSTATIC EFFECTS THEMSELVES (see Figure 2-29). http://www.argenco.ulg.ac.be/pdf/SE/COMBRI Design Manual Par...
xxxBourth Local time: 05:37 Meets criteria Specializes in field Native speaker of: English PRO pts in category: 4111
Grading comment
Thanks, the inclusion of "effect" and your copious references were very useful.
Notes to answerer
Asker: Thanks for the information and very useful references. I shall have to refer to the Client because of the context, or rather the lack thereof. The refs will be my bedtime reading before (I hope) the next project.
Reference information: Un solide est isostatique si et seulement si le nombre de liaisons indépendantes qui le lie à la fondation est égale au nombre de degrés de liberté de ce solide considéré sans ses points d'appuis. Cet état s'oppose aux états hyperstatique où leur nombre est plus élevé et hypostatique où le solide possède au moins un degré de liberté.
(Interesting diagrams to elucidate if needed) - K
So I don't think homogenous is a good definition.
kashew France Meets criteria Specializes in field Native speaker of: English PRO pts in category: 314
The translation workplace 
