Oumi Ootori Bridge

Oumi Ootori Bridge
近江大鳥橋(栗東橋
Kusatsu, Shiga, Japan
246 feet high / 75 meters high
558 foot span / 170 meter span
2007

For those who might think that Japanese bridge designers always create towers that are too minimalist and conservative, along comes the Oumi Ootori Bridge to blow this cliche out of the water.

Completed in 2007 along the E1A Expressway, the Oumi Ootori Bridge consists of side by side extradosed viaducts with four central towers, each adorned with a curving, multi-layered relief shape at the deck level.

The 555 and 495 meter viaducts consist of a 19.63 meter wide 3-cell box beam with corrugated steel walls. The hybrid style uses steel for the walls of an otherwise concrete box beam span and is popular due to the reduction in weight which leads to reduced seismic forces and smaller substructures lowering cost and allowing longer spans. Corrugated steel webs without additional stiffeners also have higher shear-buckling strength than that of flat plate steel webs. Corrugated steel webs are more easily fabricated and constructed than concrete webs. Less onsite concrete work saves time and money. Prestressing can be efficiently introduced into the top and bottom concrete slabs due to the so-called “accordion effect” of corrugated webs and the external post-tensioned tendons used with corrugated steel webs have many advantages over the internal bonded tendons.

The fancy Oumi Ootori Bridge towers are impossible for tourists to miss along local route 12 that passes below the main span on the way to the famous Miho Museum 5 kilometers to the south. Designed by world renowned architect I.M. Pei, the Miho Museum Footbridge is a cable stayed crossing with a rare circular stay arrangement supporting a clear span of 114 meters.