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Warehouse Slab on Grade Supporting Rack Post Loads 5

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ajk1

Structural
Apr 22, 2011
1,791
Anyone really experienced in design of slab on grade supporting rack post loads? If so, can you help with the following:

Is it more economical to use reinforced or unreinforced slab on grade?

Any good reference papers specifically addressing this?

If you use reinforced slab, how far apart do you place the constucution joints?
Do you use intermediate saw cuts?
What might be the typical reinforcement used?
Do you use SAFE to model it
In an unreinforced slab, where do you place the sawcuts - do you do one down the middle of the aisle where stresses are amximum?
Do you thicken the slab at edge conditions?

The post loads are about 18,000 pounds unfactored, the modulus of subgrade reaction is 100 pci. I was thinking of 30 MPa concrete (4350 psi)with a specified 28 day shrinkage not exceeding 0.035% as per CSA A23.1.

Very preliminary calculations indicate a 10" thick unreinforced slab would work. I suppose that an 8" slab with rebar with equivalent resisting moment to the plain concrete might also work.
 
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ajk1....do you do any work with esp.? (Formerly Trow)
 
Sorry...can't type...should be exp., not esp. But then if you have ESP, you would know that.
 
why do you ask? where are you located?
 
I was once a partner/affiliate. I am in Florida. At the time, my office was the US affiliate of The Trow Group.
 
Had numerous discussions with John Bickley (sp?) of TROW Toronto... way back when... my first encounter with really good geotekkie guys...

Dik
 
Dik...John was an excellent concrete guy. Had good gray matter for gray stuff! Chris Thompson and John Emery were the primary geotechnical guys at that time.
 
John Emery was involved in a couple of projects, I recall... I had forgotten about Binkley for the last 30 years... suspect he's no longer with us... he was elderly when I met him... did a lot of chitchatting with him on parkade concrete...

Dik
 
Yes, John Bickley passed in the late 90's. John Emery went on to his own firm, John Emery Geotechnical Engineering,Ltd. (JEGEL) and does both geotech and high level pavement evaluation and design. Chris Thompson has semi-retired and serves as a consultant with Trow (exp).

Had the opportunity to meet and speak with Bill Trow just before he retired (as I was being joined with the company).

They are and always have been a very professional and technically competent group. They have been led for many years now by Vlad Stritesky, who ran the roofing group during my affiliation. Vlad has done a good job with the company as one would expect from such a pro!

Ah....the memories!
 
I worked with John Bickley. Last met him at a Concrete Ontario meeting about 2005 where I made a presentation about the new Pearson Airport Garage that we designed. I had not heard that he passed away. Are you sure about that?? I am with C&W since 1964. C&W had a very proud history since its beginning in 1921. Now part of exp.
 
ajk1....not sure, but heard that. Hope I'm wrong. Not entirely sure of the agglomeration that is now exp, but I know that Trow has always been top notch. Didn't C&W merge with Trow before the exp change?

My last project with Trow was the geotechnical investigation for a large Stevenson-Hluchan project in the Bahamas (1988/1989).
 
Ron - yes Trow bought C&W in 2005
 
Little late on this and it looks like there is plenty of good info hear already.
However for what it's worth, there is a Design guide:
Designing Floor Slabs on Grade by Boyd C. Ringo and Robert B. Anderson (we have the Second Edition)

EIT
 
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