Another lesson i learned:
the spec's for my Mohawk and similar just showed about a 24 in square pad
for each post as being adequate (hmmm....3000 lbs/ sq in * 576 sq in per
pad = 1, 728, 000 lbs load capacity per concrete pad.....) . When I
worked with my grading/ concrete sub, he told me it was easier to dig a
trench all the way across the bay than to make 2 "small" square holes.
extra vol of concrete (2 in x 24 in x 14 ft = 0.17 cu yds, about $11
worth) is trivial.
Taking this thought further, position of this "band" of concrete from the
door depends on length of cars you plan to lift. I have MR2's all the way
up to F-250 pickup; I decided on 2 positions for the lift, one for the fun
cars; other for the truck (which is thankfully very reliable). so, the
band is not just 24 in wide, but 60 in wide....so the extra concrete cost
was actually $28. The labor to dig with the back hoe was just a few
minutes' worth...those guys really know how to dance with their equipment.
The final advantage for this plan is that it will accomodate any
post-to-post width/ spacing that you end up buying now or in the future.
It's probably $28 well spent. the rest of the floor will be fine with
4-inch concrete...
hope this helps
Paul
>
> Check out: http://www.bendpak.com/custom_page.isg?ref=bpakconcretereq
>
> For the biggest 2-posts, you'll need 6" of 3000psi concrete. When I built
> my
> garage, I had this done- along with rebar side to side for extra strength.
> I
> eventually went with a 4-post instead (Bendpak HD-9), but the concrete's
> good enough for either. Many lifts can be had for either 110 or 220 VAC-
> mine's 220 and needs a 25amp circuit. Depending on what you get- you may
> also need to have air available to release the safety locks.
>
> Hope this helps-
>
> -Larry
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