Aesthetic Design for Akashi Kaikyo Bridge

The Akashi Kaikyo Bridge, part of the Honshu-Shikoku bridge project, is a suspension bridge with a center span of 1990 m. When completed in the spring of 1998, it will be the longest suspension bridge in the world. The bridge is expected to be an attractive addition to the highly urbanized area of Kobe. Therefore, the aesthetic design needed careful consideration. A suspension bridge consists of horizontal stiffening trusses, gently curving main cables, a pair of vertical towers, and anchorages. Aerodynamic stability is important in its structural design. For the Akashi Kaikyo Bridge, five types of towers were compared using 1:500 scale models. Given the fabrication and erection work for the structure, a basic truss-type design was chosen. Structural concerns dictated the shape of the stiffening trusses and the main cables. In the selection of color, the surrounding environment was studied. Further research using computer graphics and scale models and site appearance tests was carried out. Greenish-gray was finally chosen from among 30 candidate colors. To lessen the impact of the immense concrete anchorages, light and shadow effects were utilized, and vertical and horizontal indentation was adopted on the surface. The result will be structural beauty and optimum harmony of the bridge with its surroundings.