ABSTRACT
Japan experienced an era of rapid economic growth from 1954 to 1973. Now, 30 to 50 years after large numbers of public infrastructure assets built in this period entered into service, the systematic and effective management of deterioration in these assets has become a major issue. Japan currently has a total of 894 suspension bridges, with a total length of 90.1 km., 92% of which are managed by municipalities. People tend to associate Japan’s suspension bridges with huge structures such as the AKASHI KAIKYO Bridge; but the majority of these bridges are medium-sized structures with an average effective span of approximately 100 m. In comparison with conventional bridges, suspension bridges require a high level of technical expertise for their effective maintenance. However, the frequent lack of such expertise at municipal management level leads to difficulty in performing construction safety evaluations and making maintenance planning decisions on the basis of inspection results. Accordingly the present research concentrates on the hitherto little-studied phenomenon of creep, which is thought to have a major effect on bridge shape. Deformations in small- and medium-sized unstiffened suspension bridges are analysed and reproduced, and stress states during these deformations along with changes in vibration characteristics and other properties are elucidated.
