Bridges

• Steel Girder

Since the strength, which is a design criterion, is improved by 23% maximum compared to conventional steel, economical design/construction due to its light weight can be performed. The feature is high strength allowing for high weldability. Preheating can be omitted or reduced in welding. It was used for the Tokyo Gate Bridge, the world-first large full-weld truss-box compound bridge, and it greatly contributed to efficient welding, quality improvement, and work environment improvement.

• Cable

With rolling-process inline-type molten salt bath heat treatment (DLP), LP treatment of wires is omitted. Steel material with a low environmental load was developed with no lead and reduction in CO2 emissions, and the world's highest strength of 2.0 GPa class was also achieved.

• Main Tower Foundation

A steel pipe sheet pile attaching the pipe joint to a steel pipe pile is continuously built in a closed shape like a circle at the site. It integrally behaves as a steel well foundation and high horizontal resistance/vertical support force can be obtained. In construction, it can also be used as temporary coffering and is excellent in economy.

• Main Tower Foundation

To build a steel sheet pile cell, linear steel sheet pile is connected in a circle and they are buried deep into the ground. Then, the steel sheet pile wall closed in a circle is filled with soil. Since it is buried deep in the ground and tightly filled with soil and it has a gravity structure with large diameter, energy absorption capability is much higher compared to the pile type. It is used as a ship collision prevention facility in ocean areas where large tankers cruise.

• Main Tower Foundation

Method by which a steel pipe provided with a "spiral blade" at the end is rotated and press-fitted. Construction with low noise and low vibration and without earth removal can be performed, and the bottom expansion effect of the blade can bring high pushing support force/pulling resistance force.

• Bridge

Weathering steel can be used without coating. Eliminating the need for a coating coat including re-coating contributes to reduction in life-cycle cost. The feature is "to prevent rust," which is the weakest point of iron due to "rust." At first, rust is generated similarly to normal steel, but dense protective rust is eventually formed on the surface with the function of alloy elements. In this way, progress of rust is controlled. An esthetic effect whereby the subdued color of protective rust matches the scenery in Japan and that it is loved as a local landmark may be expected.

• Bridge

For bridges using weathering steel, reduction in life-cycle cost is evaluated and it accounts for about 30% compared to steel bridges. However, salt environments adversely affect weathering steel, limiting its use. NSSMC has developed its original high-weathering steel NAW-TEN™, which showed improved salt damage resistance better than general weathering steel by addition of nickel. This technology received the Ichimura Industrial Award and the Contribution Award in FY1999 and received the Monozukuri Nippon Grand Award, Excellence Prize in FY2009.

• Bridge

NSSMC found that progress of rust at a coating defect was controlled by adding a trace of alloy to steel. Based on this idea, strength or weldability equivalent to conventional steel was obtained. New weathering steel for coating bridges was put on the market (CORSPACE™). The maintenance cost is reduced by extending the period until re-coating or reducing the need for re-coating.

• Bridge

A footbridge using duplex stainless steel as the main material featuring high strength and high corrosion resistance. Duplex stainless steel makes re-coating maintenance of the bridge unnecessary and contributes to reduction in life-cycle cost. In particular, it achieves no maintenance in environments where salt damage is a problem.

• Bridge

Exterior material for bridges using metal skin material (3 types: titanium, stainless steel, and coated steel sheet) with high corrosion resistance. The bridge is protected from external corrosion factors such as wind/rain, solar radiation, salt, etc. and a high corrosion preventive function protecting from corrosion factors such as condensation greatly extends the period until re-coating. In this way, the maintenance cost can be reduced. Since the panel itself has strength, it can be used as a scaffold to perform safe and definite short-range visual inspection.

• Bridge

New-type metal slab bridge using square piping for a short-span bridge (within 15 m) as the main girder. In comparison with the PC bridge, substructure reaction is reduced by about 20% to make the substructure compact. Since the girder height is low, the existing substructure can be reused when the superstructure is renewed and it is suitable for bridges on rivers in cities, and bridges having multi-level crossings with main roads or railways. Panels are produced in a factory and built on the site. Construction is fast and simple and construction in narrow places can be performed with a heavy machine.

• Bridge

A water supply channel is an important facility for water business. Most of the piping is buried under the ground. In crossing rivers, the presence is shown as a water pipe bridge. It is necessary to be safe under all conditions and to be functional over a long period of time. An esthetic element that has good harmony with the construction environment is also an important item.

• Steel Girder

UIT of Nippon Steel & Sumikin Technology Co., Ltd. is a system by which the fatigue strength of steel members is improved. The impact pin attached to the end is vibrated at high speed to apply impact to the weld area. It is effective for extension of the fatigue life at a weld toe and it contributes to reduction of the maintenance cost. We have a proven record exceeding 100 including the D runway of Haneda Airport.

• Main Tower Foundation

The metal coating method protects the surface of the steel sheet by titanium sheet or stainless steel sheet with very high corrosion resistance/durability. It is used for piers of the Tokyo Bay Highway and the D runway connecting bridge of Haneda Airport, and it meets the needs of corrosion resistance life of 50 years or more. As an anti-corrosive repair method for steel materials, Nippon Steel & Sumikin Anti-corrosion Co., Ltd. is implementing the TP method, which provides a protection cover with a titanium plate over the anti-corrosion treatment by petrolatum tape, or the method that improves anti-corrosion property by affixing titanium foils in areas where coating film deterioration or corrosion may easily occur to prevent entry of corrosion factors.