Shintotakachiho Bridge

Jump to navigationJump to search

Shintotakachiho Bridge
Takachiho, Miyazaki, Japan
377 feet high / 115 meters high
469 foot span / 143 meter span


The 3 bridges of concrete and steel in Takachiho Gorge tell a progressive story of Japan's bridge construction history. Kamihashi was the first and lowest crossing and opened in 1947 with a span of just 31 meters. In 1955 the Takachiho Bridge opened almost directly above the Kamihashi arch but with steel ribs that soar approximately 60 meters above the Gokase River. In 2003 the polygonal Shintotakachiho was completed with a deck 115 meters high.

The Shintotakachiho Bridge arch was built outward at the same time as the road deck, eliminating the need for a highline. To prevent the two halves of the arch from falling into the gorge, several cables were attached from the road deck down to the arch within each spandrel panel. The next vertical spandrel support was then built up to deck level and connected to another short span of roadway. The arch rib was built out a little further and the process repeated itself. Once the two sides of the arch were closed in the middle, the temporary cable stays were all removed from inside the spandrel panels.

The asymmetrical arch has an unusually high rise of about 164 feet (50 mtrs) making for a steep rib section of 58 degrees where it meets the foundation.

There is no other region in Japan that has as many high bridges than the Takachiho Gorge Scenic Area of Miyazaki Prefecture. Within a distance of just 30 kilometers the Gokase and Iwato River canyons are crossed by no less than 15 high bridges.

Several of these spectacular crossings were the highest in Japan including Tensho, Seiun and Unkai Bridges. The Takachiho Railway Bridge is still the highest railway crossing in Japan even if it not longer operates with regular trains.

まれに見る、多角辺形アーチ橋の神都高千穂大橋は、高千穂峡谷地域内で、タワーが100m以上の橋の中で八番目となりました。 非対称的なこのアーチには、ほぼ50mのめずらしく高いアーチライズがあり、基礎部分と結合しているところでは58度の急勾配リブセクションを形成しています。

路面デッキと同時にアーチは外側に向けて造られたため、ハイライン(高架線)を使う必要性を排除しました。二つに分かれているアーチが峡谷に落下するのを防ぐために、それぞれのスパンドレルパネル内部を通し7~8本のケーブルは路面デッキより下のアーチにつながれています。そして、次の垂直補強スパンドレルパネルはデッキの位置まで造られ、別の短いスパンの路面につなげられます。 アーチリブはもう少し外側に向けて造られ、この工程は繰り返されます。二つに分かれているアーチが中央で結合されると、一時的に使われたケーブル支柱は全てスパンドレルパネルより外されます。



Image by Japanese Society of Civil Engineers.






Shintotakachiho Bridge satellite image.


Shintotakachiho Bridge location map.