Permanent pier confusion

[Coolhand1988]

Eventually, I'm planning to have a RoR observatory with a permanent pier.

After watching numerous YT videos on DIY and commercial piers, my brother( who is DIY handy ) offered to make a DIY Pier, as it would only cost a fraction of the price.

However,  I'm more inclined to have a commercial pier instead and I have been looking at a few vendors.

With my selection narrowed down to a few,  I then watched a very interesting and slightly old YT video from a commercial company called "Astro Engineering". They explained and went into depth how many of these commercial piers are designed wrong. The main negatives were a small base, short vibration fins and the famous 'rat cage'.

As I have no experience with permanent piers, can I ask members who have, comment on their experiences?

The video below is 13 years old and probably been seen countless times, but I would be interested what experience members think?

Thanks

 

 

 

 

Edited October 24, 2023 by Coolhand1988
Correct link

[tooth_dr]

I think unless you make your pier out of a potato, it’ll be perfectly adequate.   And it’s not all about the pier itself, but what you bolt the pier to.

If your brothers offering a pier id accept that offer personally, and try to incorporate some of your preferred features into it.

I’ve had a couple of concrete piers with rats cages (poured inside a sewer pipe) and now I have a heavy duty metal pier.  Can’t say I noticed any differences.

All were incorporated/bolted onto a large sunken cube of concrete about 70x70x70cm.

 

[Coolhand1988]

Ac

6 minutes ago, tooth_dr said:

I think unless you make your pier out of a potato, it’ll be perfectly adequate.   And it’s not all about the pier itself, but what you bolt the pier to.

If your brothers offering a pier id accept that offer personally, and try to incorporate some of your preferred features into it.

I’ve had a couple of concrete piers with rats cages (poured inside a sewer pipe) and now I have a heavy duty metal pier.  Can’t say I noticed any differences.

All were incorporated/bolted onto a large sunken cube of concrete about 70x70x70cm.

 

Actually the pier will  be made of cardboard😊

As I said, I have no experience with permanent piers. I'm only going by that video.  

I plan for the cube of concrete to be around 48 inches in all dimensions.

Thanks for the feedback on your piers.

 

[tooth_dr]

18 minutes ago, Coolhand1988 said:

I plan for the cube of concrete to be around 48 inches in all dimensions

Seems very large, and a lot of digging by spade!  I have very hard rocky ground, so I had an advantage. My foundation is not too large that I can walk around the pier without touching the concrete, and I poured a separate platform to walk on physically separated from the pier foundation.

[M40]

I must admit that the rat cage discussion has always puzzled me. There is the argument that you don't need to level an eq mount so it's not necessary to have the pier perfectly level, but you do need to have a level base for an az mount. So the use of the rat cage enables easy access to the mount fixing and ability to level without having a perfectly level base for the pier. I used 4 x 12mm pieces of stud for my rat cage with no challenges.

[tooth_dr]

@Coolhand1988

This hole is 60cm x 60cm x 60cm.  A 120cm x 120cm x 120 seems ambitious 

 

[malc-c]

There used to be some "rule" where the norm was to make the pier base from a cubic meter of concrete, but as shown above, 600mm cubed seems adequate.  When considering options when  I was designing my observatory I looked at commercial offerings and to me they seemed overpriced for what they were.  In the end I opted for the traditional 6" drainage pipe, sunk into a big hole in the ground filled with concrete.  The tube was stuffed with rebar and filled with concrete, with the 12" rods from the base of the mounting plate for the HEQ5 sunk into that.

 

This then supported the EQ5 until I picked up the HEQ5 the following year

The mounting plate was made by a local company for a drink, but shouldn't cost more than £50 to have it turned, drilled and anodized.  I think at the time I saved myself about £300 compared to buying a fabricated pier made from steel.

[Coolhand1988]

29 minutes ago, tooth_dr said:

@Coolhand1988

This hole is 60cm x 60cm x 60cm.  A 120cm x 120cm x 120 seems ambitious 

 

Oops, that should of read 28 inches. The 48 inches is my ideal metal pier height.

Thanks 

[tooth_dr]

42 minutes ago, malc-c said:

There used to be some "rule" where the norm was to make the pier base from a cubic meter of concrete, but as shown above, 600mm cubed seems adequate.  When considering options when  I was designing my observatory I looked at commercial offerings and to me they seemed overpriced for what they were.  In the end I opted for the traditional 6" drainage pipe, sunk into a big hole in the ground filled with concrete.  The tube was stuffed with rebar and filled with concrete, with the 12" rods from the base of the mounting plate for the HEQ5 sunk into that.

 

This then supported the EQ5 until I picked up the HEQ5 the following year

The mounting plate was made by a local company for a drink, but shouldn't cost more than £50 to have it turned, drilled and anodized.  I think at the time I saved myself about £300 compared to buying a fabricated pier made from steel.

This is pretty much exactly the same as my last pier, and it held a mesu mount and a few telescopes with zero issues. 

[Coolhand1988]

I'm no expert but I believe that vendor was talking about the rat cage bolts on commercial piers being too far from the center. ?

I read one review on a commercial pier, where the owner was not happy with his pier "singing" and filled the inside of the pier with sand, which cured the vibration sounds.

Rat cages on cement filled piers have long support bolts and I don't think that applies to the above video!

Thanks

 

[Clarkey]

I think if you are using a long FL scope on a very tall pier, then some if the arguments in the video are probably valid. However, in most cases the seeing, optics and mount will have a much larger effect. I used to image on a tripod in the garden and then moved to a pier in an observatory and I saw no significant difference in performance. FWIW my pier is made from 10" plastic pipe filled with concrete, I have a rat cage and a brake disk as a mounting plate. Works fine. The hole for the concrete was decided by how many bags I could be bothered to carry through the house. I got fed up at about 250 kg.

[bwj]

Take a look at this thread and a few others on "Clody Nights". The pier engineering thread is long, but has lots of information. There are also a lot of other threads there where people share their pier construction.

I'm also planning my ROR.  My pier foundation will ideally be 12" diameter concrete 4 feet deep to get below frost line. 

I would definitely go for the offer to build a steel pier.

Clear Skies!

Edited October 25, 2023 by bwj
spelling

[Coolhand1988]

12 hours ago, bwj said:

Take a look at this thread and a few others on "Clody Nights". The pier engineering thread is long, but has lots of information. There are also a lot of other threads there where people share their pier construction.

I'm also planning my ROR.  My pier foundation will ideally be 12" diameter concrete 4 feet deep to get below frost line. 

I would definitely go for the offer to build a steel pier.

Clear Skies!

Thanks, I have read of frost line and the 48 inches figure. Also, I found that post over at CN with 29 pages, so I have a good read on that later.

ATS permanent piers are and look the part. Tad expensive, but I believe unavailable for the UK.

The other interesting thing about that video was the so called 'Poor Seeing' conditions having an input on these so called mounts as well.  

Thanks

[bwj]

@Coolhand1988, for me, the 48" depth is necessary for my location. You may not need to go that deep where you are. I see a lot of posts on here from people in the UK that aren't anywhere near that deep. Check with your local building code people,  they can give you a recommendation for footing depth.

Take care, 

Clear Skies!

[Coolhand1988]

27 minutes ago, bwj said:

@Coolhand1988, for me, the 48" depth is necessary for my location. You may not need to go that deep where you are. I see a lot of posts on here from people in the UK that aren't anywhere near that deep. Check with your local building code people,  they can give you a recommendation for footing depth.

Take care, 

Clear Skies!

Thanks for that advice and yes, around 24-30 inches seems more common in the UK.

 

[Louis D]

Around here, we have to get below the line where drought and flooding affect the top layers of soil.  A lot of houses built on slab foundations instead of pier and beam foundations flex and crack as the soil hydrates and dehydrates over the span of months to years.  I would expect the same to happen with pier footings not set deeply enough.

[Coolhand1988]

Thanks, I will recheck my original information on recommended pier depths. 

 

[900SL]

I'm a civil/structural engineer. Piers are like hifi.. there's a lot of balony talked out there

Foundations depend on load,  ground conditions and climate.

Base should be below frost line and into firm soil. The typical loading from astro gear is peanuts, so you don't need a large footing, unless you have a very tall pier and large aperture set up and mount.

Clays can be tricky, they may be susceptible to shrinkage and swelling.

Make sure you are below any topsoil or fill (made up ground) and don't build on silts or peat

By way of example, a 600 square footing on firm sand or stiff clay can usually carry a few tons without issue.

Piers.. vertical cantilevers. Up to two meters use steel tube or square section with  width = height/7.5 and 6mm wall thickness, or concrete with 4 x 12mm rebar and 6mm links at 150mm c/s, for typical set up

Rats cage is OK if you keep the height short and use m16 or m20 bolts 

[UKDiver]

Also could be worth checking for sewers etc. We've 9" sewers half way up the gardens around here. They could be less than 1m deep. Well within the scope of some of the UK depths mentioned here. Water mains and other utilities less likely, but not impossible.

[jjohnson3803]

Don't know how much they can handle or if one would suit your needs, but a number of people have made piers out of concrete blocks.  I think they call them Tormorden piers.  Maybe a possible alternative to pouring a lot of concrete.  Good luck!

Edited October 31, 2023 by jjohnson3803

[Carbon Brush]

On 26/10/2023 at 20:25, UKDiver said:

Also could be worth checking for sewers etc.

Definitely dig carefully using hand tools.

I discovered that British Gas and British Telecom that thoughtfully installed their services about 200mm below my driveway.
The digging man folded over the end of the venting gas pipe and retained it using a cable tie😆
Neither organisation seemed to think they should have been deeper, put marker tape above their lines, or even put it on the house plans!
They also thought it was OK to install services that shallow!🤬

When digging my pier foundation, I discovered a long forgotten land drain (pipes not joined up type) that was at my target depth.

[wookie1965]

46 minutes ago, Carbon Brush said:

Definitely dig carefully using hand tools.

I discovered that British Gas and British Telecom that thoughtfully installed their services about 200mm below my driveway.
The digging man folded over the end of the venting gas pipe and retained it using a cable tie😆
Neither organisation seemed to think they should have been deeper, put marker tape above their lines, or even put it on the house plans!
They also thought it was OK to install services that shallow!🤬

When digging my pier foundation, I discovered a long forgotten land drain (pipes not joined up type) that was at my target depth.

Putting a new fence in digging hole for post against the back wall first spade full I spotted something same as you carefully got the soil around what it turned out to be the main electrical cable supplying the house. 

Probably 75mm below the surface when I reported it they said I would have to pay to get it relaid. 

I wasn't going to pay thousands for that so I have covered it in thick metal trunking in case I move and someone else decides to replace the fence. 

I moved the post six inches away from it. 

[Louis D]

Around the US, you must call 811 to have gas and other utility providers come out for free to mark their buried lines before you dig.  Doesn't the UK have a similar service/requirement?

[Mandy D]

2 minutes ago, Louis D said:

Around the US, you must call 811 to have gas and other utility providers come out for free to mark their buried lines before you dig.  Doesn't the UK have a similar service/requirement?

I looked into this last year for work being carried out on my property and it appears that you are not permitted to dig down further than 100 mm without planning consent, other than for gardening where there does not appear to be a limit. I've never heard of anyone actually following this requirement, other than when full planning applications are submitted.

[UKDiver]

1 hour ago, Louis D said:

Around the US, you must call 811 to have gas and other utility providers come out for free to mark their buried lines before you dig.  Doesn't the UK have a similar service/requirement?

No and yes. There are several competing services charging for online access, some owned by utility companies. There are something like over 1000 organisations who may have underground assets. However a single service is growing for most of the UK https://geospatialcommission.blog.gov.uk/2023/04/05/nuar-available-to-users-in-first-uk-locations/  Scotland already had a similar system.  Various tools may be used to detect underground features and manually mark up the surface. Hand digging is still supposed to be used in close proximity. However it still needs people to look up the data and I've seen the aftermath. For me, I've only seen property damage, but I've worked with those who've had far worse.  :( Unfortunately some assume there is nothing under fields etc, yet these are the places the more strategic assets may be. Gas and electric mains may have surface markers, but water and sewerage usually don't although manholes and valve covers give good clues.

There's no single service or point of contact.