Interconnected Footings & Soil Expansion
Interconnected Footings & Soil Expansion
(OP)
Does IBC 2006 or CBC 2007 specify anything about interconnecting footings based on exapnsivity of soil?
As a rule of thumb, I think from a previous version of the UBC from the 80's (not sure), I deepen footings to 21" for medium, 27" for high, 33" for very high. If soil is low expansion of greater, I interconnect all exterior, interior and porch footings.
Do you have any comments? Do the interior footings need to be interconnected.
Any comments about IBC 2006 1805.8?
Thanks.
As a rule of thumb, I think from a previous version of the UBC from the 80's (not sure), I deepen footings to 21" for medium, 27" for high, 33" for very high. If soil is low expansion of greater, I interconnect all exterior, interior and porch footings.
Do you have any comments? Do the interior footings need to be interconnected.
Any comments about IBC 2006 1805.8?
Thanks.






RE: Interconnected Footings & Soil Expansion
Whilst being in general a sound measure, depending upon your intent and some particular structure and pattern of expected heave or settlement it may be practical or simply, just economical, not tie the strong points of foundation in a grid; only a particular examination of the case may help to decide what one would do.
RE: Interconnected Footings & Soil Expansion
RE: Interconnected Footings & Soil Expansion
Perhaps another could elaborate...
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Interconnected Footings & Soil Expansion
We also use voids under slabs and/or grade beams like Mike stated in conjuction with drilled shafts. If the voids are only under the grade beams, some soil modification may be required under the slab to keep the slab from heaving.
The Texas Section of ASCE put out a publication entitled "Recommended Practice for the Design of Residential Foundations" for what I described above.