EXCHANGE OF KNOW-HOW AND INSIGHTS WITH THE HONSHU-SHIKOKU BRIDGE EXPRESSWAY COMPANY (HSBE)

8 April 2025 – With the support of Japan’s Ministry of Infrastructure and Transport, Stretto di Messina met with the Honshu-Shikoku Bridge Expressway Company (HSBE) to discuss, among other things, best practices for monitoring and maintaining major infrastructure.

In particular, the inspection systems planned for the various components of the Strait of Messina Bridge and the ones implemented by HSBE, including through the deployment of robotics, were described. The discussions also focused on dehumidification techniques for the suspension system cables, and the types of railway equipment used.

THE HISTORY OF THE HONSHU-SHIKOKU BRIDGE EXPRESSWAY COMPANY

The Japanese company, founded in 1970 with the aim of building and operating highways and railways to connect the islands of Honshu and Shikoku, was established after a tragic collision between two ferries in 1955.
To date, HSBE has built and operates 17 road and rail bridges between the islands of Honshu and Shikoku.  

THE THREE ROADS OF THE HONSHU-SHIKOKU BRIDGE PROJECT

• Kobe-Awaji-Naruto Expressway – 2 bridges

The eastern Kobe-Awaji-Naruto Expressway, which is approximately 89 kilometres long, runs from Kobe to Honshu Naruto in Shikoku. The Akashi-Kaikyo Bridge crosses the Akashi Strait (4km) and the Ohnaruto Bridge crosses the Naruto Strait (1.3km). The Ohnaruto Bridge was opened to traffic in June 1985. The Akashi-Kaikyo Bridge, which has been in service since April 1998, is the world’s second longest suspension bridge, and its main span is 1,991 metres long.

• Seto-Ohashi Bridges – 6 double deck bridges

The central Seto-Chuo Expressway & JR Seto Ohashi Line (Honshi-Bisan Line) was opened to traffic on 1 April 1988. The upper deck is for motorway traffic and the lower deck is for rail traffic.
The motorway and railway are respectively 39 kilometres and 32 kilometres long.
This route consists of six long-span bridges (Shimotsui-Seto Bridge, Hitsuishijima Bridge, Iwakurojima Bridge, Yoshima Bridge, Kita Bisan-Seto Bridge and Minami Bisan-Seto Bridge), which span a 9.4-kilometre strait.

• Nishi-Seto Expressway – 9 bridges

The western Nishi-Seto expressway is approximately 59 kilometres long (from Onomichi to Honshu to Imabari to Shikok) and consists of 9 long-span bridges that connect 7 islands. These bridges have been open to traffic since 1979.

SEISMICITY

As Japan is one of the countries with the highest seismic potential in the world, roads, railways and bridges are designed and built to withstand earthquakes.
One of the most devastating earthquakes occurred in January 1995, which affected the Kobe area and caused severe damage.
This earthquake generated a new fracture in the underlying seabed, which caused the foundations of the Akashi Kaikyo Bridge (under construction at the time) to shift by 1 metre. However, it did not cause any damage to the neighbouring suspension bridges that had already been built.