Long term deflection concrete slab studies.

[rowingengineer]

Does anyone know of any published studies for long term deflection recordings of concrete slabs. The only study i know of is this one by Ian Gilbert & Co?

R407: An experimental study of reinforced concrete flat slabs under sustained service loads

http://www.civeng.unsw.edu.au/staff/ian_gilbert/

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it

 

[rowingengineer]

and this one

http://projects.bre.co.uk/ConDiv/concrete frame/SlabDeflections2.pdf

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it

 

[IDS]

rowingengineer - watch out for the next issue of Concrete in Australia. The theme is deflections and there will be a number of technical papers on the subject.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[ishvaaag]

There's one a bit old in ACI Special Publication 76

ACI SP 76-4
A parameter Study of factors Affecting Time-Dependent Slab Deflections
Andrew Scanlon
ACI 1982

I made a mathcad 2000 worksheet attempting to follow what stated and included here

 

[IDS]

Also Rebecca Gravina & Co. have been doing work on monitoring deflections in real structures recently.

e.g.:

http://search.informit.com.au/documentSummary;dn=492873076744937;res=IELENG

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[rowingengineer]

Doug,
Thanks for the heads up, also thanks for the reference, was able to down load it, hopefully they go back and complete the survey in a few years again, to really get some good information.

Ishvaaag,
Thankyou for the reference, unfortunately I am an excel guy so couldn’t make use of your Mathcad sheet.


Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it

 

[asixth]

There is the slab deflection in our office that I have been meaning to study but never got around to doing. I was going to run a string-line to it so I can measure the deflections and calculate estimated deflections using the theory which Prof Ian Gilbert writes about. The unknowns will be the time that the slab was first loaded (say 14 days) and the permanent loading (1.20kPa / 25psf). That will be a form of study when completed.

thread744-265955

 

[unclesyd]

Off topic but very interesting when it come to deflection of concrete.

http://www.ur.umich.edu/0809/Apr27_09/16.php

 

[JayMaechtlen]

That last one is really interesting!
- self-healing concrete!

Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[unclesyd]

The first two go together as the paper by Taylor and Heinman is from the syllabus.

http://www.ce.memphis.edu/6136/PDF_notes/syllabus_06.pdf

This is the paper referenced in the syllabus. You might be able to get this paper from the Linda Hall Library.

(J.P. Taylor and J.L Heiman, “Long Term Deflection of Reinforced Concrete Flat Slabs and Plates,” American Concrete Institute Journal, November 1977, pp. 556-561.)

These are just two that popped up along with the above.

http://www.adaptsoft.com/resources/ADAPT_TN292_floor_deflection.pdf

http://www.thomastelford.com/journals/DocumentLibrary/STBU1580106.pdf

I found the Taylor and Heinman paper but it was in Spanish

 

[racookpe1978]

Strictly anecdotal information, but the 5 foot (60 inch) span, 4 inch thick drain culvert slabs covering cleaning access ports in my neighborhood have substantially slumped in only 40 years (early 70's until 2010) from gravity alone ...

Sure, they are probably non-reinforced (improperly) , and a non-critical application, but very ugly results.

 

[rowingengineer]

unclesyd,
the paper by taylor was in the right ball park, the paper he wrote as teh basis for the paper you suggest was a hiome run.

thanks

asixth,
Let us know the results of your study, will be interesting to see.

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it

 

[unclesyd]

Your welcome and appreciate the heads up.

Was just hoping to repay you for hijacking your thread.

 

[paddingtongreen]

We had a case, back in the late sixties that got some attention. An office building, concrete floor on metal deck, composite with the beams but not the girders. The building was not occupied for two years, at which time, cracks started to appear along the girders. A review of the design said it was okay but creep had allowed the beams to deflect more, causing the beam ends to rotate and stretch the concrete above the girder.

After that, I reinforced for the fixed end moment over the girders.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[rowingengineer]

It is amazing how many eye sores can be hidden under carpet.

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it