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Apartment hunting? Avoid a rectangular layout. Here’s why.

By on June 9, 2020
A powerful 9.1 m earthquake in March 2011 shook a rectangular shape building in Tokyo forcing people out. (Source: YouTube)

A survey of 400 apartment renters by Glide, a moving company, reveals that 40% of respondents affected by coronavirus are looking for a new rental apartment.

Most budget-conscious foreign residents put ‘low move-in cost’ as the first on their list when hunting for an apartment to rent. But for those whose fear of earthquakes caused by a 9.1-magnitude that shook Tokyo and the rest of Japan, earthquake-proof properties remain high on their list. According to an article published in Gold Online, square layouts offer better seismic resistance than rectangular ones.

“Many structures in Japan have been constructed to some extent on seismic engineering ideas but some of the designs that are believed to be earthquake-resistant are not actually so,” says Mikio Koshihara, Associate Professor, Institute of Industrial Science.

So how do you know if a building is highly resistant to earthquakes and that it could protect the life and property of your family in the event of an emergency?

Structural integrity of the building

Strength, regularity, redundancy, foundations including load paths are what builders consider when designing and constructing earthquake-resistant buildings.

In Japan, shape matters. During an earthquake, the real non-linear stress-strain stage of the structure determines a building’s resistance. Square buildings are known to have less shaking than rectangular ones. A rectangle building has a long side and a short side. During an earthquake that sways sideways on the short side, residents will experience more shaking. Of course, a rectangular design can pass national standards for earthquake resistance, yet it remains doubtful if it can cover the structure’s weaknesses caused by the shape. The earthquake resistance in most of the newly built houses we find today in the center of Tokyo, are long and slim and likely to exceed the seismic resistance value limit. Even if they pass building codes, a seismic resistance value can sometimes result in not being adequate to resist stress during an earthquake. One of the reasons for that is seismic engineering. Experimental and theoretical investigations conducted under strong earthquakes show the RC (reinforced concrete) structural system independently changes its stiffness for adaptation to the scale of an earthquake. This makes the seismic resistance value of a house gradually decrease over time.

If you are looking for a home to move in, you will find that rectangular properties are abundant and actually the first to go vacant in Japan. But if you have to live in one, go instead for a square building.

About Ted Tanaka