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Cinder block pier

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#26 Gastrol

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Posted 01 February 2013 - 11:54 AM

There also is a product that you can bind the blocks together on the outside of the blocks. I've used it and it works well.

There are different names but it usually has fiberglass fibers imbedded in it

http://www.quikrete....-Stack-Wall.asp
Norm


I've used fiber imbedded stucco on dry-stacked cinder block walls and also as final render on my brick pizza oven. Resists cracks, adds strength, and very easy to apply.

#27 HunterofPhotons

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Posted 01 February 2013 - 12:33 PM

.... Rebar keeps the top part from being torn off the bottom part.
R


Just out of curiosity, have you ever seen a monolithic concrete pour separated in this manner?

dan k.

#28 roscoe

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Posted 01 February 2013 - 08:54 PM

Dan,
We rebuilt a falling-down deck a few years ago, that was built over a fairly steeply slanted backfill against a foundation, where the piers had been destroyed by frost action. There is a phenomenon called 'ground creep' that happens on hillsides, where when the ground freezes, it lifts perpendicular to the surface - it goes up at an angle - but when it thaws, it drops straight down. The piers we replaced, which were not re-enforced, had been pulled apart about 12-15" down, the bottom sections staying in place, the top parts having moved downhill in 20 or so years about 6", which of course made the 4x4 posts connected to them very crooked, and started the deck collapsing. There was enough dirt between the upper and lower part that at first we thought the initial piers were indeed only 18" tall, only after digging some more did we find the bottom halves.
Properly re-enforced ones would not have pulled apart, but in this hillside case, would likely still have begun to tip because of the creep action. We replaced the old 6" ones with 12" versions, with much larger footings, planning that the larger footing diameter would better resist tipping forces, having more area on the uphill side to press against the soil above. Because of the higher-than-normal side thrust on them, we bent 3/4" rebar into a 'u' shape, with 3 shorter pieces laid in the bottom of the U half way down the footing, spread out into a 6-pointed cross. So far, they're still straight up.
Russ

#29 HunterofPhotons

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Posted 02 February 2013 - 02:41 PM

Thanks, Russ.
I've never come across such a situation even though the bulk of my construction experience has been in New England.
It's easy to underestimate the power of frost heaves unless you've seen what they can do. Wet ground seems to command the same low level of respect as the Monty Python rabbit. "But it's just a rabbit!" <g>

dan k.

#30 StarmanDan

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Posted 02 February 2013 - 06:08 PM

Does frost affect bedrock the same as normal soil? I've seen what frost can do. During one particularly bad winter my father would go out to the pool and chop up the 4" thick ice that had accumulated each night to keep our 30K gallon pool from cracking. In the process the pool had lifted about 4" out of the ground. Fortunately we had a gradual thaw and the pool settled without cracking.

#31 roscoe

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Posted 02 February 2013 - 11:00 PM

If it's real bedrock, it's the Earth's crust, and even frost can't lift that..........but it will flake pieces off the top if there are any cracks that water can seep into...... Aside from bedrock, frozen ground will lift absolutely everything. My friend's garage/equipment shed, which is built on a re-enforced concrete slab, and has a full second floor, and often a bulldozer and log skidder parked in it, lifts about 4" every winter.
R






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