Minato Bridge
Encyclopedia
The Minato Bridge is a double-deck cantilever truss bridge in Osaka
, Japan
. It opened in 1974. It is the third-longest cantilever truss span in the world, behind the Quebec Bridge
and the Forth Rail Bridge.
Designs including arch
and suspension
elements were eliminated from consideration due to poor subsoil
conditions of alternating layers of clay
and gravel
. Instead, the designers selected a cantilever structure using high-strength steel
, to reduce mass.
Osaka
is a city in the Kansai region of Japan's main island of Honshu, a designated city under the Local Autonomy Law, the capital city of Osaka Prefecture and also the biggest part of Keihanshin area, which is represented by three major cities of Japan, Kyoto, Osaka and Kobe...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. It opened in 1974. It is the third-longest cantilever truss span in the world, behind the Quebec Bridge
Quebec Bridge
right|thumb|Lifting the centre span in place was considered to be a major engineering achievement. Photo caption from [[Popular Mechanics]] Magazine, December 1917...
and the Forth Rail Bridge.
Designs including arch
Arch bridge
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side...
and suspension
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...
elements were eliminated from consideration due to poor subsoil
Subsoil
Subsoil, or substrata, is the layer of soil under the topsoil on the surface of the ground. The subsoil may include substances such as clay and/or sand that has only been partially broken down by air, sunlight, water, wind etc., to produce true soil...
conditions of alternating layers of clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
and gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
. Instead, the designers selected a cantilever structure using high-strength steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
, to reduce mass.