The Honshu-Shikoku Bridge Project, consisting of three routes linking two main islands, Honshu and Shikoku, across the Seto Inland Sea, is a big project aimed to form the trunk road and railway network in Japan.
The western-most route, the Onomichi-Imabari highway route includes the Tatara Bridge, with a center span of 890 m, the longest cable-stayed bridge in the world. It was opened in May 1,1999 the bridge carry a four-lane highway as well as additional lanes for bicycles, motor bikes and pedestrians.
The steel towers for the bridge are 220 m high and shaped like an inverted Y after examining the wind resistance, the structural efficiency and aesthetics.
The stay-cables have two-plane multi-fan shape. A total of 168 cable were made of semi-parallel wire strands consisting of galvanized wires 7 mm in diameter covered with polyethylene tube in shops.
The ends of the strands are fixed by sockets that are resistant enough to fatigue due to bending vibration as well as that of axial force.