post & frame shed-- related to roadbed stabilization!
post & frame shed-- related to roadbed stabilization!
(OP)
OK guys, Here goes again.
I last asked for your help stabilizing the roadbed for the 1/4 mile lane to my planned home across virgin soil. Now, I'm building a simple post and frame shed in the same area as this roadbed, laterally in the same position at the base of a small forested hill. The location is in the same field I referred to in the previous thread.
Here is the problem:
-- building 200 sq ft shed(keeping it small for now) using only 8, 4x6 posts, simple lean to shed but must place the post bases below frost level-- 42" here. The grassy field here drops about 6" per 10 ft. Placement is about 20 yards from a wooded hill, with an expected increase in the rise up.
-- augering the post holes yesterday I did not get far, just the first hole. At about 3 ft I hit mud, looking in, I could see water flowing in, a few minutes later the sides of the hole were caving in! After the dust(ummm, water) settled the water level was only 18" from the top of the hole.
-- I tried again closer to the hill about 30 ft from the first (i.e. uphill slightly, maybe a foot ) and hit water again. So, now, two artesian wells! This one settled out about 3 ft from the top. So, the water table recedes a bit as the land goes uphill. No surprise.
I really want to build this shed to house some equipment over the winter before building the home next spring. Moving up the hill into the forest before the hill rises drastically is a possibility but it some real downsides I do not need to detail just now. However, doing so would likely get to a point above the water table based on auger drills.
I don't want this to be expensive for a simple and small shed. I don't want to get in a big cement truck and wreck my newly fixed lane when I KNOW now that the lane also has a high water table beneath it and was likely the main cause for all the work I put into it. Any ideas how I can place 8 dang posts for this shed without having to place concrete piers or some other costly foundation support?? OR, another way to address this is not to place the posts into the ground but ONTO something(?). . . I have some thoughts on this but will hang fire until I hear your own!
I last asked for your help stabilizing the roadbed for the 1/4 mile lane to my planned home across virgin soil. Now, I'm building a simple post and frame shed in the same area as this roadbed, laterally in the same position at the base of a small forested hill. The location is in the same field I referred to in the previous thread.
Here is the problem:
-- building 200 sq ft shed(keeping it small for now) using only 8, 4x6 posts, simple lean to shed but must place the post bases below frost level-- 42" here. The grassy field here drops about 6" per 10 ft. Placement is about 20 yards from a wooded hill, with an expected increase in the rise up.
-- augering the post holes yesterday I did not get far, just the first hole. At about 3 ft I hit mud, looking in, I could see water flowing in, a few minutes later the sides of the hole were caving in! After the dust(ummm, water) settled the water level was only 18" from the top of the hole.
-- I tried again closer to the hill about 30 ft from the first (i.e. uphill slightly, maybe a foot ) and hit water again. So, now, two artesian wells! This one settled out about 3 ft from the top. So, the water table recedes a bit as the land goes uphill. No surprise.
I really want to build this shed to house some equipment over the winter before building the home next spring. Moving up the hill into the forest before the hill rises drastically is a possibility but it some real downsides I do not need to detail just now. However, doing so would likely get to a point above the water table based on auger drills.
I don't want this to be expensive for a simple and small shed. I don't want to get in a big cement truck and wreck my newly fixed lane when I KNOW now that the lane also has a high water table beneath it and was likely the main cause for all the work I put into it. Any ideas how I can place 8 dang posts for this shed without having to place concrete piers or some other costly foundation support?? OR, another way to address this is not to place the posts into the ground but ONTO something(?). . . I have some thoughts on this but will hang fire until I hear your own!





RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: post & frame shed-- related to roadbed stabilization!
NOTES: I'm concerned that reaching the point of being "muddy" will occur significantly before Minnesota min frost depth of 42" thus making it impossible to get below frost depth for footing.
Just the same here is how I would consider doing this.
an expanded process description:
Plan-- 42" is frost depth here and I want 4" additional height for drainage slope from building to surrounding land. If my original post height for a post and frame building was 150" I will cut my post by 46"(104" now) and make up the difference with a 46" tall PVC formed concrete pier. All piers must hit the same top elevation. I realize I cannot use pre-cut 46" tubes because some will go deeper and some shallower after pile driving. I will plan to use the auger bit / skid steer to press it deeper till fair resistance is noted. Kind of like a pile driving . . . After driving and leveling, each post will have to be custom cut at top to hit planned elevation of laser line.
In order:
-- cut, say, a 60" long x 8" dia PVC tube and 80" piece of rebar.
-- set up laser to mark line for final elevation of top of all posts.
-- auger till muddy(24", 38", 43". . . ??? who knows?) , place 8" PVC pipe.
-- determine what the difference in height is between the 60" tube and the 46" needed for laser level height for top of 46" pier; cut PVC to place top at that level. (If can only hit 32", say, too bad it will be above frost footing.)
-- using only bags of dry Sacrete fill the 8" tube; plumb and level it, brace it in two directions at 90°. Add water as necessary to the column of powdered Sacrete (as the water in the bottom of the hole is dried up) and rod the mix till it reaches correct level line; drop in #4 rebar about 20" too tall and plumb it at center of pier.
-- wait a few days till the pier cures completely before further work.
-- cut off the rebar so about 4 to 6" protrudes and drop wood post with a centered, 5/8" hole in it over the rebar to center it.
-- use grade board to connect posts at bottom outside faces of posts; also mount knee braces to inside of grade boards at 45° up to posts for lateral bracing.
-- for the 2nd thru 8th posts use same final height of PVC tube regardless of penetration depth into soil(mud?), regardless of ability to reach below 42" frost depth.
Is this correct or CLOSE? Please "fix" and paste in "improved" version with a repost. thanks!
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
That 42" "frost depth" is just a cook-book thing to prevent sitting conventional footings on soil that may lift the footing. . Once freezing front gets to that water table, the freezing progress down is much slower, due to heat of fusion given off as that plentiful water content freezes. I'd not worry at all about some magic "frost depth", since the heaving, if any is above that, more likely gripping your posts sides. You have minimal "footing" at the base of the posts, so possible frost lifting from there is very unlikely if you get a little ways into the water table. So going deep to reach some magic depth is impractical as I see it. Placing proof loads on the posts as you apparently will do should be sufficient.
On depth of freezing, it all depends on many things and can vary in your area from near the surface (as in a swamp) to 8 feet or more in clean low moisture sand, depending on other things equal, such as temperature of air, insulation on surface (snow depth and grass). In your Minnesota lakes have you ever heard of 42" thick ice under a foot of snow? Very unlikely.
RE: post & frame shed-- related to roadbed stabilization!
In addition, with the one long side of the shed(22 ft) running parallel to the hill and placed on a higher perched water table, during the rainy season it is more likely to drop into the mushy ground than the other long side resting on an area where the water table is a bit farther from the surface. I can place shims between the beam and the piers as time goes by if the low side settles. . . Extending each post up from a pier could be more problematic with settling as each pier could settle differently whereas I have better load sharing with the beam plan.
AS to the frost depth, thanks, that makes a lot of sense, not to mention the overall temp of earth being about50°F preventing the water table from freezing and the fact that there is water movement through the water table continually refreshing it with constant temp water, significantly above freezing point. My biggest hope here is that the friction of the pile is enough but feel with such a small structure it should be no problem.
thoughts on these?
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
Based on what you've described all the conditions are met for potential problems for frost action - presence of free water from the high water table, mushy non granular soils that sound frost susceptible, and cold enough environment to cause freezing. It can cause substantial heaving and upward movement on lightly loaded piles. I don't have enough experience with this to comment on it - maybe another forum member can tell me if I'm totally wrong.
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
http://www.coloradochaptericc.org/pole-barn2k09.pd...
RE: post & frame shed-- related to roadbed stabilization!
I'm not worried about arguments. I read this forum to read about situations I haven't gotten into personally, and the way other engineers think about fixing or addressing issues.
It sounds to me like he's in a place where frost action could be an issue, but I could be totally wrong. From an experience standpoint I don't have enough to be confident, and I said so at the end of the post I wrote. If you have experiences that tell you it wouldn't be an issue, I'd like to hear about it and what criteria I should be looking for when identifying something like that.
RE: post & frame shed-- related to roadbed stabilization!
http://web.mit.edu/parmstr/Public/NRCan/CanBldgDig...
At the job site there may be some frost heave, but it more likely will grab those posts and do what ever lifting happens. That's known as frost jacking. But for a shed, I wouldn't care if it was mine. Going down say 6 feet, it well may still happen. I'd just go to suitable bearing in warm weather and forget about winter.
RE: post & frame shed-- related to roadbed stabilization!
The idea being to NOT extend the posts up from each pier but let the piers support the beam and build the posts up from the beam.
One more thing. Forget about heaving, I believe I got that covered. Besides the pointers already made about mass of earth at 50°f, heat of fusion, water moving through the water table there also is the great heat conduction of moisture keeping the pier area warm, and, better yet my plan is to use LOW frost footing technology also. Basically, that is placing a layer of EPS foam insulation about 12" under the soil top surrounding the pier thus preventing frost penetration. Used a LOT in Scandinavia.
LOOKS like this for a home. I will just make it circular!
https://res.cloudinary.com/engineering-com/image/upload/v1446756972/tips/Frost_ftg_wro6dn.pdf
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
As for your PVC casing....drop a water hose down the pipe with a spray nozzle on it. If you keep the hose at the bottom of the hole and on "full blast", you'll be surprised how deep you can push that pipe with the help of your skid steer hydraulics. Cheap form of assisted jetting.
You will need to consider uplift of each post, but you can just strap them down to the concrete piers.
RE: post & frame shed-- related to roadbed stabilization!
I understand Simpson makes some great post mounts that have a slot in them. Requires threaded rod, J-rod etc. instead of rebar. This makes sense to allow me to fix inaccuracy of pier placement. What do you think?
This is out 1/4 mile from any utilities so jetting would be tough without an electric pump, of course I could rent a gas pump. I will try the first hole and consider the options you offer.
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
If one has a post already set in the ground and wants to do this, the use of a chain wrapped around the part sticking out of ground makes a good grip. Attach chain to loaded bucket. Sort of the reverse of if you wish to pull fence posts. Works even on slippery stuff like PVC. Even only two wraps with both ends connected can work, but more is better.
RE: post & frame shed-- related to roadbed stabilization!
Worried about proof testing. . . what if it pulls out? plus, I will have to wait till it cures a bit . . . a few days before trying and Menard's is already pushing me out six working days for delivery of the dang 8" PVC pipe, Like you say, winter is afoot. If it pulls out and I'm out into mid-November I may be REALLY stuck(figuratively!) Plus, not sure what the pull power of the 80 HP ASV track loader is with its hydraulics but it can pull about 2000# to pick a load of heavy class 5 from a pile--guessing here.
I will not proof. Reason, hey, this is JUST a shed, a small one(200sq ft), located behind a woodrow protecting it from the SW winds in the summer and by a 25 ft tall heavily wooded hill on the North. Besides, I would rather spend the time BUILDING rather than proofing. thanks for the idea, oldest guy, just the same.
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
RE: post & frame shed-- related to roadbed stabilization!
I am a rookie owner of the loader and not sure about the hydraulics and circuitry involved. . . I will figure something out, regardless. and let you guys know how it goes. I'm hoping to get at least one in today, but have to build a guide rail for the line of piers so they stay lined up during driving. . .
RE: post & frame shed-- related to roadbed stabilization!
Let's say you instead were doing a pole building and were setting posts that also would be the columns. In order to get a downward load on that post you some how have to get your bucket load onto the post. By wrapping a chain around the post a few times and securing it to itself and then the free end to the bucket, you could apply a downward load to the post. If no place to attach, likely a long enough chain would go under and come up to the rear top.
I once was at a ham radio friend of mine and we needed to pull out some steel, copper coated, rods that he had pounded in for ground rods (lightning protection). Only about 5 inches of rod (8 feet long) were sticking out of the ground. This guy was 65 yeas old and had done a lot of outside work at his country place. Had tractors and much stuff. His comment about the chain wrapped around the 1/2" diam rod was "That will never work". Boy was he surprised at how well it did the job on just a few inches of grip. A 4 ft. farm jack was used, from Farm and Fleet.