PEMB Uplift Footing Centered on Grade Beam
PEMB Uplift Footing Centered on Grade Beam
(OP)
For those interested in a potential solution to resist uplift in PEMB (Pre-Engineered Metal Building) grade beam foundations.
- The center of PEMB base plate is 8" from edge of 18" thick grade beam.
- 23K uplift. (Example)
- 9'-0" x 9'-0" x 24" concrete footing centered approximately on center of base plate. (Example)
- Top of footing = bottom of grade beam.
- 3'-6" of footing will extend beyond outside edge of grade beam.
- Approximately 12" of soil will cover top of extended portion of footing.
- Footing has top and bottom matt of rebar.
- Anchor bolts are 41" vertical F1554 GR36 fully threaded rod with 6" bottom bend, tied to bottom rebar matt with #3 ties.
- Rebar layer #3 consisting of #5 rebar at 12" E.W. in 6" slab will use concrete slab 36" beyond perimeter of (interior portion of) footing to assist in uplift resistance.
Another practical solution is the use of helical piers as suggested by SlideRuleEra: See: thread507-389583: Soil Suction Forces
We opted NOT to use the helical piers on a project due to fear of encountering bedrock at a shallow elevation.
I hope this is useful...
- The center of PEMB base plate is 8" from edge of 18" thick grade beam.
- 23K uplift. (Example)
- 9'-0" x 9'-0" x 24" concrete footing centered approximately on center of base plate. (Example)
- Top of footing = bottom of grade beam.
- 3'-6" of footing will extend beyond outside edge of grade beam.
- Approximately 12" of soil will cover top of extended portion of footing.
- Footing has top and bottom matt of rebar.
- Anchor bolts are 41" vertical F1554 GR36 fully threaded rod with 6" bottom bend, tied to bottom rebar matt with #3 ties.
- Rebar layer #3 consisting of #5 rebar at 12" E.W. in 6" slab will use concrete slab 36" beyond perimeter of (interior portion of) footing to assist in uplift resistance.
Another practical solution is the use of helical piers as suggested by SlideRuleEra: See: thread507-389583: Soil Suction Forces
We opted NOT to use the helical piers on a project due to fear of encountering bedrock at a shallow elevation.
I hope this is useful...





