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RE: PEMB ftgs

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David,

 

We do extend the rebar from the turn down into the foundation (essentially transforming our turndown into a pier) and to date we haven’t had any problems with shrinkage cracking.

 

John Whitty, P.E.

ITAC Engineers and Constructors

804-414-1132

 


From: M. David Finley, P.E., P.A. [mailto:davidfinley(--nospam--at)bizsea.rr.com]
Sent: Friday, October 13, 2006 8:16 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: PEMB ftgs

 

You obviously have to have reinforcing connecting the footing to the turned-down edge.  Have you had any problems with shrinkage cracking in the slab at or near the column due to the additional restraint provided by the footing?  Of course, the turned-down edge will also provide restraint so maybe the additional effects of the footing are not significant.

 

David Finley
M. David Finley, P.E., P.A.
2086 SW Main Boulevard - Suite 111
Lake City, FL  32025
386-752-6400

-----Original Message-----
From: John Whitty [mailto:jwhitty(--nospam--at)itac-net.com]
Sent: Thursday, October 12, 2006 3:18 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: PEMB ftgs

I understand what you’re saying….but we we’ve being doing for this situation is this…

 

We have a continuous turndown around the perimeter of the building at frost line depth.  We then center a square footing under the column with the top of the footing being coincident with the bottom of the turndown.

 

This way we eliminate any eccentricity from vertical loads.  We use the footing and overburden to resist uplift.  Hair pin bars centered in the slab take care of the lateral loads.

 

It’s an extra step in the construction process but our subcontractors seem to love it.

 

Make sense?

 

Regards,

 

 

 

 

John T. Whitty, P.E.

ITAC Engineers and Constructors

Chester, VA

 

 

 


From: Andrew Kester, PE [mailto:akester(--nospam--at)cfl.rr.com]
Sent: Thursday, October 12, 2006 2:38 PM
To: seaint(--nospam--at)seaint.org
Subject: re: PEMB ftgs

 

Rich,

Seems like you are doing it the way I have always done it and seen it done. Like someone else said, unless you have to drop your footing for frost reasons, you just design the column footings as monolithic with the slab and the thickened edge. All my PEMB work is in Florida so uplift is usually our biggest problem, not the gravity loads. Designing as a rectangular footing parallel with the edge of the building, like a cont wall footing, could help reduce the effects of the eccentricity but it will always be there...

 

I will sometimes play around with the geometry of the monolithic footing and try and utilize the slab and thickened edge to help resist the uplift. This may let me reduce the footing size and then I just thicken and reinforce an area around the footing in the slab to help with the uplift, reducing overall concrete and using the slab that was already there...

 

HTH,

Andrew Kester, PE
ADK Structural Engineering, PLLC
Lake Mary, FL