Mat Slab with Minimal Differential Requirement

[FiniteElemet]

Hi:

I am designing a mat slab which will support mechanical equipment such that the differential settlement between the edges of the 115ft x 15 ft may cannot be more than 0.002 in. Have gone upto 48" concrete mat, still getting differential settlement. Thought someone may have experience in how to get rid of differential settlement?

Thanks in advance for helping comments.

 

[haynewp]

I would check with the geotech on using using helical piers etc. instead of ordinary soil supported, assuming that is what you are using.

 

[hokie66]

0.002" is a very tight, and perhaps unrealistic, requirement. What does your geotechnical consultant say?

 

[GregLocock]

We try and get concrete flat to 4 mm, 0.15" over that sort of distance and pay a lot for it. I do not believe you could measure to 2 thousandths of an inch over 15 feet with any reliability without using a temperature controlled environment and lab quality gear rather better than a Faro Arm.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[FiniteElemet]

Modulus of sub-grade reaction is low to begin with. I tried using higher modulus for sake of argument, you guys are right. It is long strides from what is required. Can we use some sort of continuous steel plate with floor treatment? If so, what may the connxns look like and type of face treatment for walking?

Thanks