Saturday, 18 June 2011

A big batsu for Japanese architecture?

Batsu is the Japanese word for a cross, and it means that something is wrong or not allowed.  I noticed a few of them on the pillars and beams of the house as it was going up. Perhaps I'm reading too much into it, but I can't help seeing it as someone putting red crosses where something is wrong.  And it seems to be a little critical of Japanese architecture.

I learnt in first-year engineering classes that squares and rectangles are not a good idea for a structure, as they create a mechanism. The top can swing from side to side, turning from a rectangle into a parallelogram. If it keeps swinging, as it well might in a strong earthquake, the parallelogram turns into a horizontal straight line with the ceiling meeting the floor. To stop this, you need triangles. 

Our first-year engineering project, as I remember, was to design a structure--basically a bridge-- that would hold one tonne across a span of one metre. Most people built a square-based pyramid, with a hook at the top to hold the weight, and a beam diagonally across the square base to turn the square into two triangles and avoid the mechanism. My group made a tetrahedron: a triangular-based pyramid, so there were no squares to start with. This is the basis of the geodesic dome, which is a very light structure. Our "bridge" weighed a little over half the next heaviest design, fulfilling the goal of the engineer to build something that will do the job using the least necessary resources.

Anyone can build a bridge, we were told, but an engineer will build a bridge that is strong enough for its purpose, using as few resources as possible. 

I really don't know very much beyond first-year engineering, but I can't help feeling that there's just far too much wood in the structure of the house, and it's all in mechanisms. When we're talking about shelves and internal woodwork, I'm constantly being told that solid wood is really expensive, and we need to use laminated wood, or fibreboard. Then I see huge chunks like this being used where the roof meets the walls: 

The lateral strength is coming from kenaf board, imported from Malaysia and made from a baste fibre. A package was left on the balcony the other day, which alarmed me somewhat as it has a "No wet" sign and an umbrella. The architect assured me that this just meant the contents should not get wet, and it would be fine to leave the palate out in the rain.

The kenaf board is being put around the outside of the pillar and beam structure, then the batsu can all be removed. It doesn't look very rigid, but according to this paper it seems to be strong along its length.