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Started my CGE pier with pics...and some questions

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#1 fetoma

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Posted 04 April 2009 - 06:34 PM

I went the Bigfoot Systems route for my pier and I'm ready to pour it tomorrow. I would like to ask some concrete pouring questions:

First, I'll be doing this all myself, and my only experience with concrete is post setting. Here, I will be using (15) 80# bags and mixing by hand.

Second, How much time do I have between pours before the concrete starts to set? I'll be using Quikrete 5000# mix and the outside temp. will be about 50 degrees.

Third, should I pour the Bigfoot form first and then place my 12", thick-wall PVC drain tube on the form? It's got a bit of weight to it.

Pictures:

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#2 fetoma

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Posted 04 April 2009 - 06:35 PM

Another Bigfoot BF-28

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#3 fetoma

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Posted 04 April 2009 - 06:36 PM

Pier tube:

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#4 fetoma

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Posted 04 April 2009 - 06:37 PM

Yes, I made a mess of the yard:

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#5 Strgazr27

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Posted 04 April 2009 - 07:23 PM

Frank,

I got your scopes! Tubes will be started in about a week.

I poured my bigfoot and tube all in 1 shot. Is 15 bags of 'Crete enough? How tall is the pier going to be? I used 3" of river rock on the bottom, tamped. I back filled the Bigfoot to just below the attachement ring for your size tube. I poured till the bigfoot was almost filled, added my sonotube, screwing it to the bigfoot, backfilled to grade and finished pouring. There was 2 of us doing it so it was doable. I also used 5000PSI sakrete and it setup to touch on top in about 5 hours and I pulled the sonotube off 18 hours later. I than watered it every 4 hours for 2 days afterwards. 2 coats of gloss black rustoleum and it looks sweet, 2 years later.

Unfortunately, with the upcoming pick up of a CGE Pro, it looks like I may need to cut the pier. Not a fun job.

More pictures please !

Anything else drop me a PM.

#6 fetoma

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Posted 04 April 2009 - 07:48 PM

Hi Bobby,

Glad to hear the scopes arrived safe.

The tube is 5 foot long and the hole is 3 foot deep. I figured 15 bags from the formula on the bigfoot website. I was thinking of doing it the same way you did, filling the bigfoot first, then mount the tube and fill that.

I read your CGE Pro post. Congratulations and good luck with it. Can't wait to see it. Maybe try it without cutting the pier first to see if you can get away with what you have. Oh what a mess it will make having to cut it. Lots and lots of plastic sheeting to keep the dust off of everything, or it will ruin it all. :bawling:

#7 NHRob

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Posted 05 April 2009 - 06:37 AM

Frank,
Are you planning a bldg around it or just leave the mount out in the open?

Rob

#8 Luigi

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Posted 05 April 2009 - 07:44 AM

I don't know specifically what you are planning but I've heard of problems where the base of the pier was not poured directly in undisturbed earth. The idea with this (as with footings for other tall structures like free standing radio towers) is that the concrete is intimately in contact with existing naturally compacted earth to create the greatest resistance to toppling type loads. The piers are relative heavy and short and don't topple, but they can start to wobble if they are surrounded by or sitting on backfill.

#9 skybsd

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Posted 05 April 2009 - 07:49 AM

Hi,

<snipped>
I used 3" of river rock on the bottom, tamped. I back filled the Bigfoot to just below the attachement ring for your size tube. I poured till the bigfoot was almost filled, added my sonotube, screwing it to the bigfoot, backfilled to grade and finished pouring. There was 2 of us doing it so it was doable.


The only concern I'd have (depending on depth of the hole, soil type + height and weights installed onto the pier) is that the integrity of a backfill won't be the same as that of the surrounding ground - leaving the possibility for settlement that MAY lead to pier shift at some point later on.

That said - takes nothing away from the fact that your installation is still going strong after two years.

Just a thought.., best wishes..,

Regards,

skybsd

#10 Strgazr27

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Posted 05 April 2009 - 08:20 AM

The bottom of the holes was roughly 42" below grade. This is about 12" below frost line where I live. The base of the hole is a mix of clay/sand w little moisture content. The base was wetted down and tamped with a pneumatic hammer. The base rock was than dumped in, leveled and tamped the same way. We set the Bigfoot, back filled and poured. In the uses we are using these for they are way overkill for the situation we are using them in. The use of a adjustable top plate like most use will more than allow for whatever settling may occur. I have noticed about a 1/32" change in 2 years and at this point, with the weight on the pier, I think all settling has been done.

#11 fetoma

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Posted 05 April 2009 - 08:57 AM

Hi Rob,

It will be out in the open for now since I'm tired of carrying the mount in and out of the house. No observatory plans as of yet.

#12 Ian Robinson

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Posted 05 April 2009 - 09:06 AM

Hi,


<snipped>
I used 3" of river rock on the bottom, tamped. I back filled the Bigfoot to just below the attachement ring for your size tube. I poured till the bigfoot was almost filled, added my sonotube, screwing it to the bigfoot, backfilled to grade and finished pouring. There was 2 of us doing it so it was doable.


The only concern I'd have (depending on depth of the hole, soil type + height and weights installed onto the pier) is that the integrity of a backfill won't be the same as that of the surrounding ground - leaving the possibility for settlement that MAY lead to pier shift at some point later on.

That said - takes nothing away from the fact that your installation is still going strong after two years.

Just a thought.., best wishes..,

Regards,

skybsd


This is why it's a good idea to have your GEM or wedge mounted on a separate "flotating" adapter plate that has 3 leveling bolts that are integrated into the top cap plate of the pier or imbedded into to pier , if the pier settles it is of no consequence as you can relevel the adapter plate to keep the mount perfectly leveled.

#13 fetoma

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Posted 05 April 2009 - 09:14 AM

I will be using the floating adapter plate method using 3/4 stainless hardware from Dan's Pier Plates. There will also be some rebar installed through the entire pier length and into the ground below.

#14 skybsd

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Posted 05 April 2009 - 10:23 AM

Hi,
First off - congrats on your build :)

Secondly - its really NOT my intention to put a downer on your project..,

I will be using the floating adapter plate method using 3/4 stainless hardware from Dan's Pier Plates. There will also be some rebar installed through the entire pier length and into the ground below.


Adjustable top pier plates is indeed the way to go - which is what most folks are using.

Whilst I'm not advocating your stopping / changing your intended plans, I'd be looking to consider: -

a] Settlement that causes pier shift effectively results in a vacuum created on the opposite side of the shift direction

b] Once pier-shift starts, there's really little means of knowing WHEN it will stop

c] A pier that has shifted will also result in the center of gravity of your load also moving away from the previous center

d] In addition to [c], the weight at the mount will, as a matter of course, be exponentially increased towards the direction of the shift - think of why you move counter-weights along the counterweight shaft to balance a GEM, so the greater the angle of shift, the higher the resulting effective weight will be at the mount

Just bits to consider.., that's all.

Best wishes with the build..,

Regards,

skybsd

#15 fetoma

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Posted 05 April 2009 - 11:00 AM

Folks,

There is no problem here, I just wanted to share.

#16 HunterofPhotons

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Posted 05 April 2009 - 11:48 AM

.... There will also be some rebar installed through the entire pier length and into the ground below.

If I were you I would get the assistance of someone local who has experience with concrete to help you with this project. If you aren't familiar with the basics of concrete work, you're almost certainly destined to screw it up. Fixing concrete mistakes is rarely fun.
To illustrate my point, your plan to run rebar into the ground will guarantee that your pier cracks in the future. Rebar needs to be totally encased by concrete. Rebar stuck in the ground will rust. Rusting rebar expands and cracks concrete.

dan

#17 fetoma

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Posted 05 April 2009 - 01:02 PM

Thanks Dan!!!!

#18 Strgazr27

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Posted 05 April 2009 - 04:17 PM

With piers capable of supporting small automobiles the weight we are placing on these piers is almost nothing. If you take the time to properly tamp the base material, wet down your back fill material as you go and tamp as you go, settling is really not an issue. As I said I have a 50" pier from ground level to top plate. With 1/32" of movement over 2 years I have been more than able to compensate. With a 12" diameter, the shift in COG is really nill. When properly installed and poured, shift should be almost eliminated. Take the time to know your soil, prep your base and back fill properly there should be no issues.

I havene't seen any shift in the last 5-6 months so I think I'm pretty good.

CS's

#19 nofxrx

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Posted 05 April 2009 - 04:18 PM

Agreed,having rebar completely COVERED(by ~2" at least) of concrete is a must...

As for the Big Foot idea...I dont know anything about them...
BUT,(having JUST done it,lol)I STRONGLY sugget ALWAYS using some sort of concrete "pad" around the Pier below ground level...This KEEPS you center of gravity from ever moving(short of a massive mudslide or a plane landing on it..lol)...Fact:it WILL NOT move...
UNLESS the groung directly around the pier has not been touched,or has been tamped VERY VERY VERY well..will ALMOST always give...shifting loads ALWAYS look for a weakness in the surrounding area....
My FILL around my house(which is built UP around 3' from street level,remember,Florida,hurricanes...lol) is almost rock..I dont know where they got it but it was hell getting through it..I had to use a pick axe to cut the 3'x3'x18" square hole....then,nothing BUT sand(which is NORMAL for florida..)..I made sure to wet the sand and pack it fairly well be fore digging the extra 18" hole for the tube to go into.
SO,I guess my point is,MY pier will be resting on sand...but surrounded by HARD clay and has a 12"x 5' round tube encased in a 3'x3'x12" "pad"...its locked in UNLESS the sand underneath gets washed away..which can happen..but its far less likely than a ton of concrete and plastic moving sideways (with a SH%*LOAD of momentum..!!) and hopefully stopping..

Sorry,no point yet...
IF you look at ANY builing structure with concrete beams rising out of the sidewalk or wherever...IT has a PAD or "footer" that it is holding it/encasing it/ in order to HOLD the structures center of gravity...you may not see it,but it is there.

like said,I am NOT trying to down your design..I dont know your area..you might be setting concrete inside a bed of rock..or NOTHING but hard clay...IDK!!

I WILL strongly agree though that 9times out of 10 we WAAAAAY over engineer our Piers(mine,case in point LOL) for WHAT we actually use them for...
But I will also agree that it does NOT take much to move a simple concrete pole.
I work in Electrical.We do Shopping center's parking lots.Have you guys ever seen the HUGE concrete poles that are buried directly in the ground? you stand next to them and push them..GOOD LUCK moving them..BUT,get in a bucket truck and push at the top,you can EASILY push it over INCHES by yourself!!!!It is all about your center of gravity and the force that will be pushing on it on a normal basis(gravity) and in extreme cases...WHEN you ARE USING it!!LOL

I am not trying to ruin your day Frank..I hope you know that.Take what I am saying with a grain of salt..but also,think about your ground and what YOU think is the best option(s) for YOUR situation..

BTW,my pier took 12x80lbs bags(8 of which were JUST for the PAD!!!!)and 2x60lbs bags,all 5000psi..
I think you should have MORE than enough!!
Good luck mixing by hand.I suggest a wheelbarrow for mixing.NOT 5gal buckets..did that ONCE,will never do it again!!

Good luck and have fun man!!

#20 fetoma

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Posted 05 April 2009 - 04:38 PM

Thanks for the info!!!

#21 nofxrx

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Posted 05 April 2009 - 06:26 PM

I havene't seen any shift in the last 5-6 months so I think I'm pretty good.


I hope you say the same when that beautiful CGE-PRO sits on there for a while... :praying: lol

Honestly,Bobby you said it best(and was what I was TRYING to say)..it is ALL about knowing your soil and having VERY good compaction.The reason I HAD to use a PAD around the pier is because Florida is all sand...yes,I have ~18"of REALLY hard clay..but underneath all that is NOTHING BUT sand!

Clear Skies!!

#22 nofxrx

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Posted 07 April 2009 - 06:50 PM

Well,Frank..whats going on?
How did it turn out?
How did the mixing go?


we the people(atleast myself :D )need updates buddy!!!

#23 Trebor777

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Posted 07 April 2009 - 08:36 PM

Confucious says know thy soil.

I'm getting my CGE on Thursday!!!! :jump:

#24 fetoma

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Posted 07 April 2009 - 09:13 PM

Snow here yesterday and flurries today. Too cold. I'm hoping for the weekend.

#25 fetoma

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Posted 10 April 2009 - 11:35 AM

Well, I poured the pier yesterday. I intended to take pictures along the way for you folks, but when I dumped three 80# bags of 5000# Quikrete into the Little Tikes swimming pool and started mixing.... :jawdrop:. Holy Cow!!!! I about broke my back!!!! It took 12 bags, almost 1/2 a ton, by myself. So I'm sorry there are no "pouring" pictures. I will take some later for you folks. ;)






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