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Archive for January, 2012

It’s still winter outside. They keep telling me it’s an unusually mild winter this year, but twice this week I’ve woken up to more than a dusting of snow. Certainly enough to sledge in, and needs brushing off the car as it’s too much for the windscreen wipers. Still, I’m not complaining. I quite like the stuff.  Besides, it’s still warm indoors and I get to catch up on some reading.

Lately I’ve been catching up on one of my current favourite blogs – BLDGBLOG and this morning came across an article on this image:

Fort Moore Hill High School (Pound Cake Hill, Signal Hill) being moved across Temple Street and Broadway, Los Angeles, 1886

Apparently, the town wanted to move the building to another site and found a contractor who claimed to be able to move anything anywhere. However, after getting the building halfway down the road, the contractor changed his mind, said it was impossible and the building was left. It’s a shame it wasn’t left up on its stils – it would be an incredible sight!

I got to thinking about the engineering and mechanics of lifting a building off a hill and moving it down the road, and all the calculations that needed to be done to check it could actually be done at all. I presume it would have involved lifting, sliding, rolling and then lowering down what appears to be some distance. All that done without the aid of lovely computer modelling or big lifting gear.

Among the first great engineering feats to use computer modelling was the Sydney Opera House. The architect, Jørn Utzon, originally designed the shell-shaped roofs with parabolas of ‘indeterminate proportions’. Only after building lots of scale models with the engineers Ove Arrup, did they finally come up with a solution based on sections of a sphere.

It’s all very well coming up with an idea to do something on a grand scale, even how it looks and functions. Knowing it’s going to do what you said it would do, and proving that beforehand, is a task in itself.

I’ve learnt to my cost that just believing in something isn’t enough. As the pieces I make get bigger, and the numbers of people coming to see them increases, it’s ever more important to ensure they work structurally.

Lately I’ve been spending far more of my preparation time immersed in engineering calculations. To float the spires on river Nene I had to submit detailed plans with calculations showing how they float, stay upright, and how they will behave in strong winds and flood conditions. So I now know how to calculate the forces generated by fast flowing water, wind resistance and how concrete used as ballast behaves differently in water than above water.

NeneNine

I’m also currently looking at alterations to the Drop piece to open up the inside space, which means calculating the effect of wind on large areas of fabric – both loose and under tension.

drop at crummock water

Part of the beauty of doing temporary installations is making things which are just too fragile to be permanent out of materials not designed to be permanently sturdy. That way you can really push the materials to the limit without worrying about how long it’ll last. The downside is that very often you end up doing stuff that’s never been done before with untried and tested methods.

When James Cropper Papers originally asked me what I could do with paper, I said I’d love to build a bridge in the lakes out of it. When I subsequently said the bridge would not only take people walking on it, but you could ride a horse over it, the gauntlet was well and truly thrown down.

I’ve long been a fan of Shigeru Ban’s paper architecture. The Japanese architect builds incredible structures using paper tubes as the primary material, including this bridge at Remoulin, France in 2007.

Shigeru Ban uses rolls of paper formed into tubes for his paper structures. These are good sturdy forms to start off with, but the real beauty in his pieces is in the engineered steel and wooden joints which direct the load down the tubes’ strongest side. The resulting buildings, pavilions and roofs are elegant examples of geometric design. However, I wanted a more purest approach for my paperbridge using sheets of paper. Just paper. Only paper.

Just to make things interesting, calculations for such a structure don’t exist. Instead, as with Utzon’s curves in Sydney, most of the design work is going to be done through scale models of ever-increasing size. This one from last week can clearly support its own weight in water. Which is a relief. Although I’d calculated it probably would.

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