difference between slab on grade and mat foundation 1

[cad0211]

What is the difference between a slab on grade and a mat foundation?

 

[oldestguy]

One usually is thicker than the other and column loads usually are greater for the thick one.

 

[MotorCity]

Slabs on grade usually fail by punching or large cracks that separate.

Mats usually fail by insufficient bearing capacity or rotation due to differential settlement. They are typically thick enough to preclude shear or flexural failure in the concrete.
Concentrated loads are usually more evenly distributed through the thickness of a mat than a slab due to a mats higher stiffness and rigidity.

Also, depending on the size, mats could be considered mass concrete.

 

[Ron]

Slabs on grade are very lightly loaded. They are typically unreinforced or lightly reinforced for crack control. Mat foundations are intended to support heavy column loads and are intended to "throw the loads" lower into the soil profile but at lower stress levels because of the large area. This reduces settlement and decreases the potential for isolated bearing capacity failures of individual footings.


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[oldestguy]

This old guy can't help but liken the advice you received from Ron to a refrain we have heard up here in Wisconsin. As corny as it might be here is what comes to mind when Ron comes on. "When you say Budweiser you've said it all".
Somehow get "Ron" in that refrain. Try "When Ron speaks ...."

 

[Ron]

OG...you are a kind and very knowledgeable engineer. Wish I could "bottle" your knowledge and experience. All I know came from having mentors like you who were good engineers and kept my thinking in line until I could do it on my own!

Thank you, Sir.


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[SlideRuleEra]

I second OG's comments about Ron's knowledge, experience, and ability to provide understandable explanations of technical topics.

http://www.SlideRuleEra.net

 

[Ron]

Thank you SRE! You're knowledge and experience have informed me, guided me and pushed me to be better over the past 15 years. I owe you many lunches!


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