Abstract
Exradosed bridges are recently increasing as a suitable bridge type between cable stayed bridges and box girder bridges, and the past tower height of exradosed bridges with three spans have been restricted under 10 to 15 meter. On the other hand, two span bridges supported by both ends have better precondition on stress fluctuation and displacement. It means that structural parts can be downsized with increasing tower heights. In this study, we analyzed characteristics of three main parts (tower, girder, cable) and tried to optimize a structural system. As a result, we found that the most suitable tower height is about 25-30 meter, which is twice of the past examples. This result was confirmed through a construction, and shows a new approach to bridge structures.
