When it comes to high maintenance, Hiroyuki Fujikawa is at its beck and call. And that goes for long maintenance, too. In fact, everybody involved with the Honshu-Shikoku Bridge Authority (HSBA) takes the repair and monitor process of some of the world's biggest bridge spans seriously.
Fujikawa, however, has dedicated his golden career years to bridge maintenance--a field where he has become known as a master inventor. His ability to assemble solutions has led to the development of: dry-air injection system for steel box girders; non-destructive inspection system for suspension bridge hanger ropes; countermeasures of vibration for suspension bridge hanger ropes; painting robot system for steel box girders; development of electro-deposit corrosion protection system for underwater steel structures; and an anti-corrosion system using dry-air injection for suspension bridge main cables.
Fujikawa's ability as a bridge caretaker is prominent, but his contribution to the design and construction of his land's titanic crossings, including world record-holders Akashi Kaikyo and Tatara, is equally impressive.
On June 9, 2003, the International Bridge Conference Awards Committee placed Fujikawa among the bridge engineering giants of the last two centuries by honoring him with the John A. Roebling Medal for lifetime achievement, which is sponsored by Roads & Bridges and the Engineers' Society of Western Pennsylvania.
"I was surprised to hear the good news and flattered," he told Roads & Bridges. "I really appreciate the fact that people evaluate me so highly."
Disaster relief
As a child, life on the islands of Shikoku for Fujikawa was filled with plenty of running and jumping under the warm sun. He enjoyed playing both volleyball and baseball, but there was only so much land designated for exploring. The absence of bridges meant Shikoku was a distant relative of the main island of Honshu. Even the delivery of the morning paper was delayed. Ferry boat accidents, however, hit too close to home. The worst occurred in 1955, when Fujikawa was a freshman in high school.
"It triggered public demand to construct Honshu-Shikoku bridges," he said. "When that happened I dreamed that these bridges would become a reality."
The ferry disaster of '55 pushed the government to conduct feasibility studies into possible bridge alignments across the Seto Inland Sea. In the meantime, Fujikawa pursued his passion. He received a bachelor of science degree in civil engineering from Kyoto University in 1962 and earned a master's degree in the same field two years later.
Fujikawa's first step into the road and bridge industry came with the Ministry of Construction, where he assisted in the construction of the Seto-Ohashi, Ohnaruto and Innoshima bridges. His first true civil engineering test came during the creation of the Trans-Tokyo Bay Highway. A deep sea and soft soil made construction of a tunnel and the creation of a man-made island especially difficult.
"It was a hard project, and it was also in an area vulnerable to earthquakes," said Fujikawa.
Fujikawa, however, showed little weakness in his field and moved up to serve as the head of the Planning Division, Road Bureau, for the Ministry of Construction; the director of the Kyushi Regional Construction Bureau; and the director of the Road Bureau for the Ministry of Construction. It was as Road Bureau chief when Fujikawa again put his skills and leadership to the test in a time of tragedy. After the Great Hanshin Earthquake devastated the region, Fujikawa led the effort to check the soundness of the Akashi Kaikyo Bridge and restore the trunk road network in the Hanshin area.
Greatness, however, was still on the horizon for Fujikawa.
While serving as executive director (1995) and vice president (1996) for the HSBA Fujikawa played leading roles in the construction of the Akashi Kaikyo Bridge--the world's longest suspension bridge--the Kurushima Kaikyo Bridge--the first triple suspension bridge--and the Tatara Bridge--the world's longest cable-stayed bridge.
The Akashi Kaikyo Bridge is a three-span, two-hinged stiffening truss girder suspension bridge spanning a total of 3,911 meters, with the longest section measuring in at 1,991 meters. The height of the towers is approximately 297 meters. Fujikawa played a major role in the implementation of the following technologies:
* Scour protection using filter units for underwater foundations;
* Development of underwater non-disintegrating concrete;
* Countermeasures by tuned mass dumpers for vibration of towers;
* Development of high-strength steel wire (180 kgf/mm2);
* Suspenders covered by polyethylene tubes;
* Development of large-scale moveable expansion joint (+/-1450mm); and
* Development of cable dehumidification system.
The dehumidification system for suspension cables was perhaps the most impressive technological breakthrough. The process involves the combination of dry-air injection and air-tightness by a new type of cable wrapping system using rubber-wrapping covers. Fujikawa advanced the research methodically to improve the air-tightness and simplify the process. As a result, he succeeded in the development and practical use of another type of cable wrapping system using S-shaped wrapping wires. The wires come in close contact with each other when they are wound on the main cables.
The Kurushima Kaikyo Bridge consists of three bridges. Bridge No. 1 (960 meters) is a three-span, two-hinged stiffening box girder suspension bridge. Bridge No. 2 (1,515 meters) is a two-span, two-hinged stiffening box girder suspension bridge and the third (1,570 meters) is a single-span, two-hinged stiffening box girder suspension bridge. Here, crews used another Fujikawa innovation called the electro-deposit corrosion protection system for underwater steel caissons. This system involves making uniform deposits sealing on the surface of the large-scale underwater structures without diver manipulations. It contributes to the maintenance for the existing underwater steel structures under fast tidal currents.
The cable dehumidification system also was installed during construction.
The Tatara Bridge is a three-span continuous cable-stayed bridge with a steel box girder and PC girder. Total length is 1,480 meters and tower height is approximately 226 meters. Supporting the deck are 168 cables.
Expanding minds and spans
Now that many of the major bridges are in place, Fujikawa and the HSBA have concentrated efforts in the bridge maintenance sector. Constant monitoring, however, is not always for the sole purpose of retarding the aging process. Fujikawa, who has been president of the HSBA since 2000, also has helped supervise the collation of bridge performance data from every span. Not only does this type of research aid in the upkeep of the spans, but it gives the HSBA the opportunity to learn new techniques and improve the life-cycle costs of future bridges.
"It's tough maintaining astronomical sums of bridge maintenance data," said Fujikawa. "Since we have a limited amount of staff members effectively maintaining the bridges, the maintenance performance data method helps."
And there is always that dream of something bigger--and better. HSBA's Long Span Bridge Engineering Center promotes research and development into all aspects of long-span bridge technology. Engineers offer advice around the world and have assisted several mega projects.
"Bridge spans will be longer and longer, but I think 3,000 meters might be the limit," said Fujikawa.
