Development of materials

Concrete

Underwater desegregate concrete

Development of an underwater concrete to build enormous substructures in a short time

For the Honshu-Shikoku Bridges, it was indispensable to develop underwater concrete with excellent quality and workability.

Based on numerous construction tests and research over many viewpoints in several years, it became possible to use prepacked concrete in the Seto-Ohashi Bridge. Considering the results of this experience, underwater desegregate concrete was developed to further improve the economic and rapid construction for the construction of the Akashi-Kaikyo Bridge.

Highly workable concrete

Highly workable concrete, in which high-quality, high-volume concrete placing is possible

The mass concrete with dense structural steel reinforcements and reinforcing bars are placed using a large pump and manual vibrators. And it was difficult to improve the workability while securing quality.

When constructing the Akashi-Kaikyo Bridge, we used highly workable concrete, which was developed based on new concepts after conducting numerous experiments. The development of this highly workable concrete made it possible to rapidly construct high-quality mass concrete in several anchorages, including those of the Akashi-Kaikyo Bridge.

Steel material

High-strength wire

Development of high-strength wire, a key player in reducing the weight of 2,000-meter-long suspension bridges

If conventional wires with a strength of 160 kgf/mm2 (1,570 N/mm2) were used, then the Akashi-Kaikyo Bridge would require 2 cables with a diameters of 1,000 millimeters on each side.

Therefore, we developed wires with a strength of 180 kgf/mm2 (1,760 N/mm2) which has no problems in strength or other aspects of quality.

As a result, with applications of a reasonable safety factor of the cables, we were able to use one cable with a diameter of 1,100 mm on each side of the Akashi-Kaikyo Bridge, which made a great contribution to the economical construction of long-span bridges.