Seto
A shipbuilder’s company housing on a cliff that views beautiful and calm Seto Inland Sea, where small islands float.
This project is expected to revitalize a local industrial city while serving as comfortable accommodations for 37 families. On the roof that extends from ground level uphill, the rooftop plaza, a rare public space in the hilly town spreads.
The town is poising on steep hill. On the hilltop are village forests, downhill, is ocean. Lack of flatland deprived the residents of enough public space to gather and hold events. Taking advantage of slope topography, we tried to create a public space architecturally.
What we planned was three-layered structure for habitation half overhanging a cliff. The rooftop with a superb view of Seto Inland Sea has direct access from the north road via the grand stair, and is made open to the public as a rooftop plaza. Under the overhang is another public space with a close atmosphere that covers people from rain.
Two light courts that reminiscent of Cave Dwellings in China are at the same time used as paths to move down to the residential area. They let enough light and breeze in otherwise dreary central hallway and drastically improve lighting and ventilation in there and each room.
A shape like a ship that waits for its launching ceremony is not just a design. It’s a figure that embodies true balance of architectural autonomy, requirements from the city, environment, structure and economy and echoes with a ship, an existence that finds its identity in “balance”.
Technical explanation
Foundation piles had to get enough distance from the cliff edge in order to create a large public space on the roof without stressing weak cliffs. So we adopted cantilever erection method. The adaptation was enabled by “continuous structural walls” that function as 3-story-high beams, and “prestressed concrete (PC) cables” that run in them curved, tensed according to the stress.
Efficiency of a method to put PC cable in the curved line has already been confirmed theoretically. However the method hasn’t virtually been applied even in the world due to the difficulty in practice. Means, this was the leading-edge technical trial. With this technical breakthrough, I’m sure this new rational structure would be a common one.
Let me add as aside that the tower residence part with a splendid view serves as a counter weight to stabilize the balance-shaped cantilever building volume.
Masahiro Harada
