erecting my pier-advice appreciated

[seeker372011]

OK my pier from star optics has arrived-now i have to erect it

I wont actually be doing this for a while-I have promised my daughter that I wont have any geeky/nerdy/astronomy stuff in the backyard till she has had her 18 birthday party-but after that I have approval from both daughter and SWMBO to go ahead. So I have time to work out what is to be done and plan it.On the other hand I have never done anything like this before.

its going to be an EQ6 and my ED127 on the pier plus guidescope etc

initially a pier and then one day some sort of an enclosure

so any advice whatsoever would be most welcome-I have absolutely no idea where to even start but think its something I'd like to do myself rather than pay exhorbitatnt amounts to someone else

thanks in advance!

[[1ponders]]

That's great news Narayan! (Geting a pier for a eventual permanent setup).

From memory the recommended mass of concrete for your base should be around 6x the load at the end of the pier. If you plan to eventually put something a bit more substantial up top one day I'd suggest overkill. You never know, you might have to put a PME and 12.5" RCOS on that hunk of concrete one day and you really don't want to have to dig it out just to put a bigger piece in. ;)

[alan meehan]

Hi narayan
good to see you are planning a pier .I have a eq6 mounted on top of my pier with a 8"scope guide scope & extras.not sure what soil you have but it does make a difference were iam the soil has been backfilled and is reactive clay which expands &contracts depending on the weather dry or wet.what i did was dig a hole 700 wide by 800 deep and lined the sides with coolite foam before i poured the concrete which took 10 bags to fill using quick set concrete,you have got to be fast as this stuff goes of .quick ,if you are going to put a housing around it later add some height to allow for the floor.my pier is dyno bolted in to the concrete using 8"dyno bolts and is rock solid:thumbsup:Hope this helps Cheers alan

[seeker372011]

thanks for that Alan and Paul..do you need shuttering before you pour the concrete?and do you need any steel in there?

[bert]

I personally would recommend using steel reinforcing in the concrete. Is your pier adjustable at the top or is it levelled at the bottom? If it is adjustable I personally would weld threaded rod to the reinforcing steel in the pier itself.

I would also recommend NOT using quick set concrete, it is not structurally rated and it eats aluminium. Use standard concrete, its a lot easier to use and you will end up with a way better trowled finish, and is many times stronger.

Brett

[seeker372011]

thanks for that Brett..its adjustable at the top

[ChrisM]

Hello Narayan,

I'm not a concrete expert but from the research that I did prior to building my pier last year I would agree with the advice in the previous posts. That is, definitely use some reinforcing steel, to help hold the block together, and you can specify the strength when you order ready-mixed concrete. From what I can gather, it is the quality and amount of "rock" (eg. blue stone) in the mix that enhances the strength. I have heard that some pre-mixed concrete (ie. hardware store type - just add water variety) has some very cheap "rock" in it.

I think "ordinary" concrete, like that you'd use for a slab around a BBQ for example, is typically 20 MPa strength. Concrete used for structural purposes is typically 40 MPa I think.

My concrete pier and block is probably oversize, but I used 25 MPa concrete with an abundance of steel reinforcing in the block and pier itself.


Hope this helps,
Chris

[seeker372011]

thanks thats all helpful advice

Narayan