"Swingman" wrote in message
...
"Mark & Juanita" wrote
Lee and Mark,
Residential ... it's a "crawlspace" foundation with void space under the
grade beams.
And you're right, the void space is for "heaving" soils, typical of the
clay in this specific area (east Travis County, Texas), said soil type
being particularly destructive when a rainy period follows drought
conditions, the latter being the case the past few years.
Many of the homes in this area, built on slabs and without taking the soil
conditions into account in the design, have had to be torn down recently.
I usually build "structural slab with void space" foundations in this part
of the country, but they are usually "slab on grade" and not crawlspace.
We felt that a "structural slab with void space" foundation would have
followed suit with the others, thus this design.
Thirty 16" piers, with 36" bell bottoms drilled, to 21', with 40 yards of
3500 psi concrete in just the grade beams, and probably enough wood in the
forms to build a small house.
$$,$$$,$$ ...
We start framing in two weeks ... there was a potential
problem/possibility with a bad batch of concrete delivered to someone on
the day we poured the grade beans, so I'm waiting on the 28 day break test
to see how the compressive strength turns out, although the 14 day break,
just two days ago, finally exceeded the design mix.
On top of that, it's a "straw bale" house, very similar to the "Straw Bale
Residence" he
http://www.strawbale.com/straw-bale-photos/
I'm well versed in traditional construction (which is why I was hired for
the job), but it's my first rodeo with straw bale wall construction ...
I'm enjoying the challenge! 
Now, I just need to figure out how to hang kitchen wall cabinets on a
straw bale wall ... 
Reminds me of that old biblical wisdom of not building your house on sand.
You are going in the opposite direction. Building it on piers. Building it
solid.
It is sort of like the way that they are now building tall buildings on
glacial till. Since the ground liquifies during earthquakes, they need to
go deeper, to bedrock, to make the building's foundation solid.
This has got to be expensive. Any idea on how the costs breakdown in terms
of a conventional foundation? Is this twice as expensive?