Japanese Architecture Flaws 

     Tradition Japanese architecture is beautiful and amazing.  Often built with large wooden members, ornate design, and curved tile roofes, these buildings are recognizable to most, even those not very firmiliar with Japan and its history.  These beautiful buildings are masterpeices built over the ages, but there lie within some major problems that only surface during times of unusual stress on the buildings.  One such time was in 1995 when Japan was hit by an earthquake.  The Hyogo-Ken Nanbu Earthquake hit on January 17, 1995. 

     Thousands of people died, many more thousands were injured.  Many were shocked and couldn't understand why there was such catastrophioc failure in the wooden buildings in Japan.  Wooden buildings are often praised as being more earthquake resistant because they are able to withstand minor flexing and movements while concrete (the most common alternative) typically crack and suffer major damage due to the fact that concrete can't bend at all without being damaged.  Of the 55,000 buildings that completely collapsed and the 32,000 buildings that were partially ruined, nearly all were made from the traditional wooden architecture. 

     Tile in a bed of sand is used for the roofing in Japan in many places both traditionally and currently.  The weight ratio of the tile and sand roof compared to the wooden walls is similar to putting a small book ontop of a house made of playing cards.

     While that is a bit of a dramatization, you can see with too much weight on top, it may still stand but just a little bit of unstability or pressure on the walls and the building with the weight on top would fall. 

     Building foundations are also to blame in the situation.  Many old post and beam constructed buildings are simply held in place by the weight of the building.  

     This is bad because if there is any unstability in the ground (ie an earthquake) the building can shift and fall off of the foundation it was on.  Connectors are needed to make sure the building won't shift and slide off the ground/concrete below it.  Aside from that, the foundations minimize the movement of the ground.  This was very important since much of the area was built of fill soil and marchy land.  The area was built up from two islands and the ground wasn't solid. 

     Shear walls were also part of the problem, or rather the lack of shear walls.  Shear walls keep other walls from falling over or collapsing from lateral forces.  Basically they help walls stand up straight.  With open inside spaces there are often posts but not entire walls or walls perpendicular to eachother.  The wall perpendicular to another wall is the best shear wall and these were lacking in many of the older buildings. 

     The earthquake and the destruction it brought were astounding, and even more so because Japan had claimed to have designed so much to be earthquake proof.  While the beauty of Japanese architecture is known around the world, it needs to be carefully modified so as to prevent disasters and maintain their intergrity even under above normal stresses. 

Citations:

1:  http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html

2:  http://nisee.berkeley.edu/kobe/tobriner.html

See also: Japanese Architecture