Tokyo Bay Bridges: Yokohama Bay Bridge

The City of Yokohama is just south of Tokyo along Tokyo Bay. The Yokohama Bay Bridge is a viaduct that includes a cable-stayed bridge that connects Daikoku and Honmoku Piers in Yokohama Harbor. Yokohama has a busy port clustered with piers and human-made islands that were dredged from the Bay. The Yokohama Bay Bridge is part of the Shuto Expressway.

The Japanese are proud of their bridges and so bridge owners provide parks, walkways, and viewing platforms so that visitors can appreciate a bridge's form, much as Hokusai did for the Ryogoku Bridge 200 years ago. The Yokohama bridge is a symbol of the City of Yokohama and it was carefully designed to appear beautiful from the parks and hills surrounding the bridge. Moreover, a walkway and viewing platform have been provided on the bridge.

The Yokohama Bridge has a double-deck truss superstructure with six vehicle lanes on the top and bottom decks.  The bridge has 55 m (180 ft) vertical clearance to allow big container and cruise ships access into Yokohama Harbor. The suspension cables have a fan arrangement between the towers and the girders. The main span is 460 m long and the side spans are 200 m. Because this area has large earthquakes, the bridge was designed to allow the heavy superstructure to move out of phase with the towers during strong shaking.

Japan had a huge spurt of infrastructure development in the 1980s and 1990s (much like China is going through today). The Yokohama Bridge was completed in 1989. 

Tokyo Bay Bridges: Yokohama Bay Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo Bay Bridges: Aqua-Line Bridge

Tokyo Bay is really big and so considerable time and effort has been spent to get people and goods across the Bay. The biggest effort so far has been the Trans-Tokyo Bay Highway. A 4.4 km long elevated highway carries vehicles into a 9.6 km long tunnel under Tokyo Bay.  The project includes a giant ventilator shaft in the middle of Tokyo Bay to supply fresh air to the tunnel. The highway goes from Kawasaki City on the west side of the Bay to Kisaruzu City on the east side of the Bay.

We were taken to visit the project in 1994, a couple of years before it was completed. The steel box girder segments were made continuous after they were set onto the 'Y' shaped piers. Span lengths decreased gradually from the two 240 m center spans.

Tokyo Bay Bridges: Aqua-Line Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo Bay Bridges: Rainbow Bridge (3)

Another interesting thing about the Rainbow Bridge is the prominent anchorages for the suspension cables. The anchorages include elevators to the south and north walkways on the lower bridge deck.  The north walkway provides views of Tokyo and the south walkway provides views of Odaiba (and of Mt Fuji on clear days). The walkways can pitch and roll when there's a strong wind. The anchorages also include observation platforms for viewing Tokyo Bay.

Note how the Yokoso Rainbow Tower (on the left side of the photo) matches the color and shape of the anchorage. It was built in 1995, two years after the bridge.

Tokyo Bay Bridges: Rainbow Bridge (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.