In 33 different locations, from Aomori to Sendai, where he surveyed the destruction after the recent tsunami, Tanaka found that “Pilotis” architecture came through the tsunami much better than conventional architecture. In some areas, buildings of that style were the only buildings left standing.
“Because Pilotis type architecture has no walls, there is nothing to resist the energy of the tsunami,” says Tanaka, “so the tsunami flows right through, without resistance.”
“Pilotis” derives its name from one of the five principles of “the new architecture” enunciated in the 1930s by Le Corbusier, a French architect of international fame who had considerable influence on modern Japanese architecture. In English it’s known as “pier type architecture.” It consists of putting the building on piers and making the first floor free and open to allow a sense of space.
“Piers refine a building’s connectivity to the ground,” writes the architect Fabian Cartwright, an English follower of Le Corbusier, “and allow for parking, gardens or driveways, while allowing a sense of lightness and floating (above the landscape).”
However, in Japan, where space is at a premium and everyone owns a car, it’s most frequently used for parking lots. In the Kobe earthquake, it seemed to be a recipe for disaster. Many structures and mansions built on piers to allow space for cars collapsed in the earthquake. In the tsunami, just the opposite occurred.
When Tanaka surveyed the ruins of Wakabayashi Ku in Sendai, he noticed in areas where the tsunami was less than four meters high that Pilotis buildings survived with much less damage. Surveying other parts of the Tohoku, where in some areas building a house on piers to make a parking space beneath it was popular, he found that of the 11 Pilotis type buildings surveyed, the entire living quarters built on the second floor on piers had survived.In Kessennuma, a husband and wife watched from the second floor of their house as the Tsunami rolled down on them in full fury. In their area it was about 2.5 meters high.
“Our cars and bicycles were all swept away, but there was almost no damage to our house,” the husband said. “We watched in horror as the two houses across the street from us were entirely swept away by the tsunami.”
Tanaka thinks the Pilotis construction may be the key to rapid reconstruction of the disaster area. He is against banning reconstruction on low-lying areas swept by the tsunami and moving towns en masse to the high ground.
Tanaka says, “Finding the right construction methods for homes is the key to using the areas near the coastline. Using the Pilotis method of construction will mean that rebuilding can move forward rapidly.”
The Kobe earthquake caused a considerable stiffening and revision of Japan’s building code to cope with earthquakes, and Pilotis structures are viewed with mixed feelings by some Japanese architects.
When challenged about the poor results that Pilotis type architecture showed in the Kobe earthquake of 1995, Tanaka pointed out, “If the amount of steel used in the piers is increased and the piers themselves are strengthened, then wooden homes, which are light weight, can be built on the piers, and they should be able to stand up to earthquakes. This is a good chance to use Japan’s high level of architectural technology.”