「国道45号

Many countries around the world have plans to construct super long-span bridges including a new type of cable-supported bridge. Realization of long-span bridges requires development of new technologies to lead to reduction of the construction costs. For crossing wide straits, application of multi-span suspension bridges over 3 spans is one of economical solutions. However, structural behaviour of this type of bridge has not been fully clarified. In this paper, we focused on the ultimate strength of multi-span suspension bridges, and especially parametric analysis was carried out on the elasto-plastic behavior and load carrying capacity of the suspension bridge systems with different sag ratios and the number of spans.

A multi-span cable-stayed bridge is planned for the Osaka Wangan Expressway Western Extension. Because A-shaped steel pylons are more than 200 m high, wind-induced vibration is a concern. In particular, the main pylons are prone to out-of-plane vibration in the completed system because the out-of-plane direction of the main pylons are not supported by cables. So, we conducted wind tunnel tests using a three-dimensional elastic model of the A-type pylons to determine the cross-sectional shape of the pylons with high wind stability. In addition, based on the wind observation data at the bridge site, a reasonable fatigue verification method was studied.