Paver Pier Base

[coldlegs (Stephen)]

Paver Pier base

Started chewing over my summer project of building a permanent
pier and a concrete base. The base was going to require either
bucket loads of cement bags and a lot of work or a contract delivery
to fill the hole etc etc. Then it dawned on me that I had about 170 old
cement pavers (20x20x4) leaning against the fence doing nothing and
unlikely to ever be used again. What if I dug a hole 70cm x 70cm x 66
deep and I …

1/ Put 4-6cm or so of cement plus re-enforcing mesh on the bottom to
form a level base.
2/ Put some re-enforcing mesh around the outside.
2/ Put pavers in a 3 x 3 format with about 1 cm spacing between each.
3/ Put cement over the top about 1 cm thick with re-enforcing mesh
across the top linked to the side mesh. It would be about 4cm thick at
the sides.
4/ Did another 11 layers to get a 70 x 70 x 60 cube of locked pavers/cement.

I figure it would require about 9 (20Kg) bags of quick setting premixed
cement assuming 0.009m3 per bag. That I can cope with. Don't need a
cement mixer (well maybe a baby one). Don't need a cement delivery.
Do it at my own pace and it would be very low cost.
Can anyone see any problems with the idea? One I can think of is the
pavers are dirty and slightly mouldy so they would need a wire brush scrub
before use. I'm also thinking about doing 8 layers at 3x3 then
4 layers at 4x4 so as to give some tilt resistance although I'm not sure it would need it.
Any ideas as to what the mesh size should be?
Comments anyone??
Cheers
Stephen

[Cosmic (Daniel)]

Hmmm im assuming that your going to dyno bolt your pier down..correct. Sounds solid, but the mixture of pavers and concrete could be the problem. I'm not entirely sure how well the concrete will form to the 170yr old pavers, im no expert but I would be more incline to to dig a A shape hole and fill it with just concrete forming a stable wedge underground platform. I think that would if you did this form work around the pier/pipe or beam then it could work out to be very solid. Then again visual or astrophotography, and what setup do you have kg?

Thats my 2c take it as you will, just my thoughts.

Cheers
Dan

[niko]

I'm no expert either and I sometimes think the piers described here are a tad over engineered but,

it seems to me that unless you vibrate the concrete you run the risk of airpockets between the pavers that the concrete won't flow into and thus potentially causing problems further doen the track as areas of weakness or for groundwater to seep into and undermine the whole thing.

that's my 1.5 cents worth

niko

[jenchris (Jennifer)]

Not a good platform since it will crack the first time it gets frost in it.
Throw in a few pavers, sure, but don't make patterns.
2 in concrete - throw in a few pavers - dump in a couple of bags of concrete dump in some more pavers (broken but clean is best) vibrate them in mesh and more concrete more pavers and vibrate or at least jiggle it so that the pavers settle.
Use the pavers as fill not structure.
I threw a load of bricks into mine - saved me about three bags of concrete

[leon]

Your strength in this will only be in the last top layer of pavers, sorry.

Leon

[coldlegs (Stephen)]

Yes. I thought the idea might have hairs on it!! Ok. Let's try a different tack. Now I need to set the scenario first. I'm living in the suburb of Elizabeth (Adelaide/SA) which is noted for it's extremely reactive clay subsoil and the sight for the mount is on a recently paved area between my house and my new shed/garage. The ground under the pavers is compacted paver fill/rubble and I intend to have a small (2.5metre?) observatory over the pier/mount and do some imaging.
From what I have read in the website posts and thousands of responses about this subject I'm almost certainly screwed and will have a substantial movement throughout the year due to varying levels of rain/soil moisture. So, where to go from here?
Given that I may have to adjust the level and possibly some minor rotation of the pier more often than usual I think I might take advantage of an idea first mentioned on this website by Steve (kinetic) in this post.
http://www.iceinspace.com.au/forum/s...ght=clay+laser

Steve used a laser mounted on the base of his mount pointed at the wall of his house to make the adjustment easier. I'm thinking if two lasers are mounted on my NEQ6PRO with one pointing seven metres East to the wall of my house and the second pointing eight metres North to the fence and once the pier/mount is initially levelled/aligned it should be possible to easily re level and realign the set-up at any time.
If that works, then the next question is what needs to go under the pier? As Steve (Kinetic) pointed out that whilst there is considerable evidence that a concrete block is best, with a very reactive soil you may be kidding yourself. As this lot will be inside an observatory and nobody moving around I'm beginning to think if I remove some pavers and put a 1.5 metre by 1.5 metre x 10cm reinforced slab it would do as well as could be expected on extremely reactive soil.

Any thoughts/ comments very welcome.
Cheers
Stephen

[leon]

Maybe you should forget about the pier altogether.

If you have a decent mount, mounted on a decent tripod, you can easily stay aligned, like so many here do.

Drag out your set up and start getting it polar aligned, and when you know you have it right draw a tight circle around each tripod leg where it sits on the pavers.

Remove the tripod and in the center of each circle use a masonry drill bit and drill down about 12-15mm.

With that done all you have to do is plonk the same legs of the tripod into those drilled holes, you are now back to where you started, aligned.

Leon

[coldlegs (Stephen)]

Leon
Yeah you're right about drilling some holes in the pavers. I did that some months ago and it's holding alignment reasonably well. I guess the question is do I leave it like that and simply put an observatory/shed over and it is it possible to do imaging on it? People do it star parties so I can't see why a permanent NEQ6PRO tripod wouldn't work. Maybe it's all this chit chat about "I'm going to build a super solid pier so I can do imaging" that's thrown me a little. I still like the idea of using lasers to correct for movement.

Cheers
Stephen

Originally Posted by leon

Maybe you should forget about the pier altogether.

If you have a decent mount, mounted on a decent tripod, you can easily stay aligned, like so many here do.

Drag out your set up and start getting it polar aligned, and when you know you have it right draw a tight circle around each tripod leg where it sits on the pavers.

Remove the tripod and in the center of each circle use a masonry drill bit and drill down about 12-15mm.

With that done all you have to do is plonk the same legs of the tripod into those drilled holes, you are now back to where you started, aligned.

Leon

[leon]

Stephen, at the end of the day it is your call, and if you want to try the pier thing than go for it, just don't want you to go to all this work and find out that it really doesn't make any difference to your imaging.

Many here do some fine imaging with tripod alone, and with a little fine tuning and practice you can easily be one of them.

When I was imaging i did have a pier, and it served me well, but my situation as with others here are all different.

There is no reason why you cant have a small observatory and have your stuff on a tripod inside it.

If you try this nothing is lost if you find it unsatisfactory, and you can still construct your pier later, however if you do the pier first and find it unsatisfactory it would be harder to go back to the tripod as the pier would be in the way.

Like I said it is your call, do what you feel is right for you.

Leon

[coldlegs (Stephen)]

Thanks for that Leon
It's good to know others have done both and found no problems with using a tripod and like you said it gives me a lot of flexibility in the future.
Cheers
Stephen

[jenchris (Jennifer)]

drive a pile in - it won't move - some stumpy houses have been standing 120 years without a WOODEN pile moving.
A concrete pile will go into soil like yours a fair way I'd guess - but it won't react to soil swelling or drying out - not if it is in far enough

[leon]

Sorry Jennifer, but yes it will, complete houses move with soil dryness or dampness

Leon

[niko]

I think the idea of setting up the tripod and marking it out is the best first step - you could still use the lasers I guess.

My only concern is if the soil is extremely reactive then won't the fence footing and possibly even the house move thus making the laser alignment inaccurate?

[coldlegs (Stephen)]

Jennifer
I've decided to go with Leon and intend to use a tripod for the next year or so. By then I should know how well it works and if needed I can dig a hole for a conventional cement block pier base later. It's interesting to note that I was at one stage thinking about making the pier by welding up six pieces of steel to form a hexagonal mini pyramid pier which when you think about it, it's a mini tripod. It would have been easier to make in my back yard than to source a large steel pipe or make a concrete pylon. Now I got to think about how to cover the mount and scope so it can be permanently left mounted.
I'm tending toward a colour bond shed arrangement as those kit observatories are quite pricey. More thinking needed.
Cheers
Stephen

[coldlegs (Stephen)]

Niko
You're probably right. The house is well protected by cement and patios/carport roofing but the fence might be a problem. May be better if I use the 5000L rainwater tank as a target.
Cheers
Stephen

[Paul Haese]

Hi Stephen,

just a couple of things. There is concrete and there is cement. Concrete has stones in it and cement only has sand and concrete powder in it. Cement is used for sticking bricks together in walls. It does not have the same strength as concrete. Concrete would not fit down spaces of 10mm, only the slurry would go down and it would need to be vibrated as suggested. A concrete plug is the better solution.

Now I reckon that digging the pier footing hole just a bit further is what you want to do. Reactive soils such as here in SA can be handled with more weight. Go to 1 meter with 700mm x 700mm. That will give you around 2 tonne of material when set and rain will not move that vertically or horizontally. If it does you are having a flood.

Stability is the most important part of have a pier for imaging. The main idea is that you want to be able to walk around this without vibration. This happens at star parties and some subs are lost. An enormous mass is cheap to construct and only has to be done once. A permanent pier will allow for later imaging rigs of larger sizes without the expense of digging it up again. Over engineering is best, being under will lead to frustration.

Use this idea for when you do construct the pier.

[coldlegs (Stephen)]

Thanks for that advice Paul. It's good to hear from a local astrophotographer with experience of the local Adelaide clay. This thread has crystallised some issues in my head about what I really want and how to progress my hobby. What cheeses me off at the moment is the constant set up and alignment plus the inevitable “why isn't it working now?”, “what haven’t I connect” etc. So although I've said I would be happy to run with the tripod I've decided “stuff it all” I'm building a pier. So a permanent set-up is now at the top of the agenda. An observatory/shed and a pier base . I've started to bite the bullet and ordered a colour bond shed 2.26m x 2.26 and think I can turn it into a flip top observatory without too much trouble. Haven't got the room for a roll off type.

http://www.abscodelivered.com.au/sho...iation_id=2305

Sometime this week I'll get the 0.7m x 0.7m x 1m hole dug and filled with “concrete”. Any suggestions for the pier? I'm kinda inclined towards one with lots of gussets down the side as opposed to a straight pole job. Is there anybody making them in Adelaide? Doubt it!
Cheers
Stephen

Originally Posted by Paul Haese

Hi Stephen,

just a couple of things. There is concrete and there is cement. Concrete has stones in it and cement only has sand and concrete powder in it. Cement is used for sticking bricks together in walls. It does not have the same strength as concrete. Concrete would not fit down spaces of 10mm, only the slurry would go down and it would need to be vibrated as suggested. A concrete plug is the better solution.

Now I reckon that digging the pier footing hole just a bit further is what you want to do. Reactive soils such as here in SA can be handled with more weight. Go to 1 meter with 700mm x 700mm. That will give you around 2 tonne of material when set and rain will not move that vertically or horizontally. If it does you are having a flood.

Stability is the most important part of have a pier for imaging. The main idea is that you want to be able to walk around this without vibration. This happens at star parties and some subs are lost. An enormous mass is cheap to construct and only has to be done once. A permanent pier will allow for later imaging rigs of larger sizes without the expense of digging it up again. Over engineering is best, being under will lead to frustration.

Use this idea for when you do construct the pier.

[Paul Haese]

I used a place at Edwardstown named metal fabricators. I have used them several times now and they make good piers. Use an 8" pipe with gussests (4) and that should get you there.

For the concrete get some mesh and tie that together in a cube about 100mm short of the actual hole all the way around. Put it up on some small blocks in the hole and you are there. Then just dynabolt the pier down. Making sure the bottom of the pier has a nice wide base plate.

Once you have that setup you can forget about movement forever.

[mozzie (Peter)]

hi stephen

forget the pavers,concrete with mesh is the go...
cement is a product that makes
1 concrete mix 4 parts dry mix(sand &gravel) 1 part cement mix it in a barrow if no mixer use a mattic to mix it if you have no larry.
2 mortar 6 parts sand,1 cement,half fireclay,half lime,bycol nice creamie mix for brickwork..
if you need advise on depths and lenghts of base and quantities i can help!!!!!

[coldlegs (Stephen)]

Paul
Do you have any plans for an NEQ6pro pier or should I ring them up and say "I want one like you made for Paul Haese "?
Stephen

Originally Posted by Paul Haese

I used a place at Edwardstown named metal fabricators. I have used them several times now and they make good piers. Use an 8" pipe with gussests (4) and that should get you there.

For the concrete get some mesh and tie that together in a cube about 100mm short of the actual hole all the way around. Put it up on some small blocks in the hole and you are there. Then just dynabolt the pier down. Making sure the bottom of the pier has a nice wide base plate.

Once you have that setup you can forget about movement forever.