Placing posts behind geogrid wall
Placing posts behind geogrid wall
(OP)
I have an allen block wall that is eight feet tall. The wall is supported by geogrid reinforcement placed at 24 inches vertically. We want to place a four foot high fence with fence posts that are two inches in diameter behind the wall after the wall is constructed. It seems to me that this would damage the geogrid and compromise the integrity of system. How else does one place these posts behind wall. During construction? Cutting holes in geogrid? Any thoughts





RE: Placing posts behind geogrid wall
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RE: Placing posts behind geogrid wall
I intend to include the post locations on the grid cut-sheet.
With the intention that the posts are installed simultaneously with the grid. In my opinon, this will DAMAGE the grid the least.
Think of the alternative: The fence/guardrail crew comes in later, uses their truck mounted auger to "drill" the holes for the guardrail, and what do they do, but rip though 2, maybe 3 layers of grid with the auger.
There is no way they would "dig" the holes, and cut the grid with a razor.
I suppose, a better way would be to specify a jersey barrier or other such gravity barrier.
Huh. Maybe.
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Craig T. Bailey, PE
www.bailey-associates.com
RE: Placing posts behind geogrid wall
RE: Placing posts behind geogrid wall
thanks
craig
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Craig T. Bailey, PE
www.bailey-associates.com
RE: Placing posts behind geogrid wall
You have two options: an independant foundation or an augered one. For an independant foundation you can construct a slab say 250mm thick by 1000mm x 1000mm or so wide and put your fence posts in that. (Size of foundation dictated by the moment on the post of course).
Alternatively just dig the holes through the grid. If the wall is built properly the soil will be stiff enough to allow you to cut through the grid without moving the facing blocks - if not well you will have a problem. The MSE mass is not going to behave any differently just because you have a 250mm wide hole cut through a couple of layers of geogrid.
RE: Placing posts behind geogrid wall
RE: Placing posts behind geogrid wall
The fence posts are 60.3mm dia and are being augured in the granular backfill. The augured hole is 250mm and 917mm deep. We will be going though 2 layers of the geogrid.
The SBGR is being driven and is located such that the post will not hit the longitudinal ribs of the geogrid but will actually "split" through the traverse ribs.
RE: Placing posts behind geogrid wall
Craig
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Craig T. Bailey, PE
www.bailey-associates.com
RE: Placing posts behind geogrid wall
ps. I haven't forgotten about forwarding you those pictures - just have to remember when I am home to get it off my home hard drive.
RE: Placing posts behind geogrid wall
It is like saying that you can't drill a 1/4" hole in a RC wall because you might go through one rebar.
RE: Placing posts behind geogrid wall
I wouldn't lose any sleep over it.
RE: Placing posts behind geogrid wall
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RE: Placing posts behind geogrid wall