- Thread starter Adam W.
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I had a visit this evening from the computer technician upstairs.

The first thing he said when he set eyes on the drawing was*"That looks like a Julia set"*.

The Julia set video.

IkamusumeFan, CC

So we're off down the fractal and infinately repeating geometric shape rabbit hole, with the next stop the Fibonacci spiral.

The first thing he said when he set eyes on the drawing was

The Julia set video.

IkamusumeFan, CC

So we're off down the fractal and infinately repeating geometric shape rabbit hole, with the next stop the Fibonacci spiral.

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Anyways, I did have a good peep into the fractal rabbit hole and decided it's best to wait for another time.

I am re-visiting my tenuous link with Frei Otto, Ted Happold and Michael Dickson and taking a good look at tensile structures, mobius strips, soap structures and assorted bendy wooden whatnots, to prove an idea that I have been mulling over after a conversation with an architect at the weekend.

Once the metalwork shop opens, I'll knock up a copy of one of these Frei Otto models, with the intention of trying to do someting.

As starter, the tension on the soap film is the same at all points and in all directions.

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Cheers

Martin

It's the last day tomorrow and we shut at 13:00 for the big change over, so things are going to be quite hectic.

A week off from thinking about vaults............

Spent the day with the casting technician making a mould for the Horse of Selene.

She is a very good mould maker who also works at the Royal College of Art and was loving the work, as she normally makes flat moulds, so this was a bit of a dream job for her and I got preferential treatment for the day.

We started by pouring a thin coat of silicone over the head to pick up all the detail.

Followed by layers with added thixo in the silicone to give the thin detail coat some structural strength.

I think it looks rather fetching with an almost paisley finish.

It's set to dry for the week and we'll start on making the split mould part of the process.

It's nice being able to call upon people who are experts in their field to get a masterclass in subjects like this.

Next week I'll start on the models for the vault.

Spent the day with the casting technician making a mould for the Horse of Selene.

She is a very good mould maker who also works at the Royal College of Art and was loving the work, as she normally makes flat moulds, so this was a bit of a dream job for her and I got preferential treatment for the day.

We started by pouring a thin coat of silicone over the head to pick up all the detail.

Followed by layers with added thixo in the silicone to give the thin detail coat some structural strength.

I think it looks rather fetching with an almost paisley finish.

It's set to dry for the week and we'll start on making the split mould part of the process.

It's nice being able to call upon people who are experts in their field to get a masterclass in subjects like this.

Next week I'll start on the models for the vault.

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Essentially, an analogue computer...~~I won't be in to show anyone around today if anyone was considering turning up.~~

Anyways, I did have a good peep into the fractal rabbit hole and decided it's best to wait for another time.

I am re-visiting my tenuous link with Frei Otto, Ted Happold and Michael Dickson and taking a good look at tensile structures, mobius strips, soap structures and assorted bendy wooden whatnots, to prove an idea that I have been mulling over after a conversation with an architect at the weekend.

View attachment 120045

Once the metalwork shop opens, I'll knock up a copy of one of these Frei Otto models, with the intention of trying to do someting.

As starter, the tension on the soap film is the same at all points and in all directions.

Possible.....but, experimentum periculosum et iudicium difficile.Essentially, an analogue computer...

The casting technician is very happy with the progress so far and I have every confidence in her ability to make a decent mould to cast from. I'm only going to cast three heads and the first one will probably be destroyed.

It must really help having expert assistance, far less chance of stray bubbles.

Good luck

Martin

She knows what she's doing which is good enough for me. I'll worry about the vault and she can worry about the mould making.

Using the principals of Hookes law, I've been making scale plaster models of the optimum load path for the vault. They seem to work well and it's good fun making them. They are not as accurate as a chain, but they are visually pleasing because they are so thin (3-4mm) and can take a load (500g of loading so far).

The one standing, represents the correct span and the arch has the same length of circumference as the vault. This doesn't look like the model at all and is incorrect, as it's too steep and the curvature representing the load path lies outside the thickness of the masonry vault. So I need to make one with a greater span and a longer circumference to produce a shallower vault.

The second one at the front represents the shallowest curve which can be contained within the masonry, but I think it's too shallow and the span is too great, so I'll make a third (the Goldilocks arch) which will be steeper with a shorter span.

My plan is to try to estimate the minimum thickness of the masonry wall required to support the vault, using the difference between the span of the arches. I'll then compare this with the actual wall thickness (which I don't know at the moment) to see if the thickness can be calculated with any accuracy using a piece of rope or chain. I'll allow for a minimum masonry thickness of 9" (about 3"on the model) at the apex of the vault to produce a steeper catenary.

All this has nothing to do with the timber model, but I want to fully understand the masonry vault and produce some physical research to impress the judges at my first major assessment in a couple of weeks. I'm also interested to see if a practical vault can be designed using geometry and a chain, but without any mathematical calculations.

So far I've shown that it can be designed using a compass and geometry and two measurements, but can I prove that it will stand up under load ?

Concrete Thickness Gauge Might be able to recommend someone near you.

Concrete Thickness Gauge | PCTE

Pete

Model #3 and I think I can roughly estimate the thickness of the masonry required at the wall to be.......

16" with a 10% margin for error and I don't know the thickness of the top of the vault. The top of my plaster curve comes out at 10", but the masonry could be thinner, which would make the walls thicker. Going through all this leads me to believe that the thickness of the walls could be calculated with a chain using a drawing containing the whole of the curve including the tas de charge.

The master mason is going to measure the thickness of the interior masonry wall for me on Thursday, if she remembers.

Out of interest, the first plaster curve can now take a point load of 1kg at its apex. I'll test it to destruction at the end of the MA.

16" with a 10% margin for error and I don't know the thickness of the top of the vault. The top of my plaster curve comes out at 10", but the masonry could be thinner, which would make the walls thicker. Going through all this leads me to believe that the thickness of the walls could be calculated with a chain using a drawing containing the whole of the curve including the tas de charge.

The master mason is going to measure the thickness of the interior masonry wall for me on Thursday, if she remembers.

Out of interest, the first plaster curve can now take a point load of 1kg at its apex. I'll test it to destruction at the end of the MA.

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They used something similar on the NY Metro too. I think it was an Italian company which made those.

Years ago Grand Designs did a house based on this technique at Marden, just a few miles from where we live - cycle past it frequently. It did collapse at one point during the build.

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Grand Designs | The Crossway Eco Arched Roof | Hawkes Architecture

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A gravity defying eco-build in Kent

Looked a bit shabby last time I saw it (earlier this year).

Crossway on C4's Grand Designs. Known as one of presenter Kevin McCloud’s favourite projects, admired for its innovation and beautiful hand-made parabolic arch.

www.hawkesarchitecture.co.uk

Explore the amazing Grand Designs Eco Arch in the Weald of Kent, one of the most ambitious projects to ever appear on the show.

www.granddesignsmagazine.com

Looked a bit shabby last time I saw it (earlier this year).

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I am also happy to report that the first plaster model can now easily support a point load consisting of a bucket of screws, an 18" tenon saw and a pair of pliers stacked on top of each other.