Hanshin Expressway Large-scale Renewal Project
No.3 Kobe Line, vicinity of Minatogawa
~opened in 1968~

Compact Structure to Satisfy Strict Requirements

Expressway Large-scale Renewal

Constructing a bridge at this site with severe locational conditions requires elongation of the interval of bridge piers and downsizing and weight-reduction of the foundation and superstructure.
However, these solutions turned out to be the cause of accelerating cracking in the deck slabs and girders of this bridge over time.

Expressway Large-scale Renewal

Fatigue cracks are progressing at various parts of the steel deck slabs and steel girders.
The causes of such cracking are presumed to be deterioration by composite factors (combined deterioration), which include the special structural features such as lightness in weight and susceptibility to deformation, application of repeated loading due to increasing traffic volume of large vehicles, and the impact of the Great Hanshin-Awaji Earthquake.

Back in the Days of Construction

The bridge had to satisfy various severe conditions, including the restriction posed by the construction site, which was an intersection of national highways and therefore limited in space, and a compact structure including a foundation smaller than the standard in addition to an elongated distance between bridge piers necessary to stride over the river.
When the Great Hanshin-Awaji Earthquake occurred, it gave serious impacts to the bridge, including the bridge piers removed from the girders.