Pier Design, something a little different.

[Perkil8r]

 Been thinking last night about piers Would a 8" dia concrete pier be big enough in dia? I have a cunning plan to achieve a nice shape to a pier of that dia, well I say that, it would be fluted so the outer edge of the flutes would be approx 210mm dia, the inner most approx 160mm dia ish. Height would be approx 1.1m then a short steel pier bolted to the top of about 12-18 inches, the mount would then bolt to the top of that.

 

The plan is to make a concrete pier that looks "pretty" when not in use as it will be outdoors. The top section will be removable so that it leaves a concrete pillar with a fluted design with an Armillary Sphere on top of it. Something like:

 

 

Around the bottom of the pier will be something like:

 

 

The idea for the pillar is to use some corrugated plastic roof sheet rolled into a tube, then fill it with concrete and of course steel / stainless steel bars and threads sticking out of the top. Does a pier of those dimensions sound strong enough? I've only gone off those sizes as that's the size of sheet I can get easily and without having to join any sheets. Each join could leave a bit of a rough edge, but that's no big deal as long as I get it on the outside of the curve if that makes sense, that way I can use a grinder to smooth it off.

 

Your thoughts?

[Tweedledee]

I can't quite visualise these "flutes". Is it musical as well as being a real smart looker?

I love the idea, but I feel that the diameter of your pier may be on the lower size limit. It is only as strong and rigid as its smallest dimension of 160mm. You would need to make sure it is a top class concrete mix so it does not erode and crumble away eventually.

[Perkil8r]

I could make it larger dia, it will just need planning to make sure the joins end up on a point I can get a grinder to. I have thought about your suggestion of an old lamp stand or bollard, but they are very expensive by comparison, and this way I can make it the right size rather than being limited by the size of reclamation I can obtain. I agree, it is a bit difficult to visualise, but I think it will work, just need to get the sizes right. I've emailed to find out the size of the centre slab so I can make an informed decision on it. If not I may resort to cobbles instead but I like the idea of a circular paved area around it.

 

Concrete mix is a very good point, I need to do some research into that. I'd like to think I can get a finish similar to that of the ornaments you see in the garden centres etc, and a similar colour too, almost white.

[dawson]

I'd imagined Mike meant something like this:

 

http://www.house-martin.com/images/products/orac_column/components/k4002_3.gif

 

James

[Perkil8r]

A little yes, but the peaks will be smooth radiused as well as the troughs.

[Tweedledee]

I reckon you should use a good quality masonry paint to give the concrete pier exactly the colour you want, hide any imperfections and most important of all protect it from the elements.

Without some paint, it will be subject to erosion by freeze/thaw action in winter, it will absorb moisture and corrode your reinforcement. When steel corrodes inside concrete, the corrosion products take up more space than the steel it came from and the pressure will crack off the concrete cover. For the size you are considering, there will be minimum (or less than minimum 50mm+) cover. This "fluting" is likely to provide a larger surface area for such attack to occur.

Better to throw these spanners in the works at this stage than have it start crumbling one night half way through an imaging run

[Perkil8r]

Hmmmm good points. I propose to use stainless bar for that very reason so as to try and prevent the rust expansion issue, afterall it's only a few quid more on the job but will stop any bursting issues. Good call on the paint, I had imagined leaving it bare, I guess an off white colour and then do one of those fancy wash things to it so it looks weathered might do the trick. I don't want it to look too perfect or else it may spoil the look.

[+RonC]

I left the white plastic pipe on and just filled with cement, better finish I think?

[Perkil8r]

I'm wanting something looking a little rustic rather than too perfect.

[+Ibbo]

a good concrete mix will last you long enough

[Perkil8r]

I don't foresee it needing to last more than 5 or 6 years at most, I hope to be moved on by then. Do you think the corrugated plastic idea will produce a decent pillar?

[BAZ]

If you want to age concrete a mix of peat and yoghurt does the trick. After a while it looks like it's been there donkey's. It doesn't affect the concrete either.

[Perkil8r]

What's the consensus then, paint or no paint?

 

If you want to age concrete a mix of peat and yoghurt does the trick. After a while it looks like it's been there donkey's. It doesn't affect the concrete either.

 

That's what I was trying to remember! Spot on Martyn