I'm in the process of building a 21 by 32 foot cabin on piers. For the piers I went all out with footings ended up 100% more than code using high design factors. 28x 28 square foots like bigfoots but square. 12" piers with 60" below grade reinforced with 1/2 " rebar x 3. Piiers are in 3 rows , 9' spacing across, 10' length wise.
Above grade piers are 36" to top of concrete from grade. In the center of each pier I've got a 1" or 3/4" (1" at corners) threaded rod. 18" above concrete.
WHat Ihad originally planned was the beam sitting on a steel plate with the height of the plate adjustable by nuts on the threaded rod. So I would have to drill through the beam and set the beam down over the rod.
Now I'm thinking that the beam 4 - 2X12s could be two parts both 2 - 2x12s with spacers in between. Difficult to describe. But would allow not to drill into beam but in to a short section of 2x12. Then attach both sub beams to spacers. Would put 2x12 where ever there is a splice and 2x4s other places.
Any comments
I'd buy it if you thru bolt the whole works together with 1/2" bolts with nuts and washers , about 20" OC staggered one up , one down . About 2" from the edges of the 2 bys .
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2"
X X
( 20" ) ( 20" )
X
2"
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BTW I'm not a structural engineer and you should run it by your building dept. if one is involved.