Features

Features

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Installation work can be done easily, in a short period, and at a reduced cost.

  • We offer high cost performance products that can be installed quickly without any need to weld or bolt the main members together.
  • These products are light and tough, so they are easy to transport and erect.
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These products can be installed without problem in both narrow and urban areas.

  • We can make bridges that are 50% lighter in maximum than conventional concrete bridges, enabling the necessary construction machinery to be reduced in size. In addition, these bridges can be erected in narrow areas.
  • We have a wealth of experience not only with general road bridges, but also with small-scale bridges in urban areas, forest road bridges in mountainous areas, and agricultural road bridges.
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Reduction in maintenance costs

  • By using steel members with weathering steel specifications that inhibit corrosion, the costs of initial painting and repair painting can be eliminated.

Features

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Our wealth of achievement supports our world-class products.

  • Our high-strength steel wires are used in the Akashi Kaikyo Bridge, which is the longest suspension bridge in the world. Additionally, we delivered some 4,200 tons of HT690 and HT780 steel for the stiffening girders of this bridge, aiming at reducing the pre-heating temperature. This was a world first.
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Weathering steel which can reduce maintenance work

  • Weathering steel can also be used unpainted. In addition to reducing repainting costs, it has a good reputation for its sedate color tone.
  • This steel contributes to reduced life cycle costs and reduced environmental impact.

Example of use

Overview of example

Tokyo Gate Bridge.

  • Japan
  • Entire length: 2,933 m
  • World's largest-scale fully welded continuous truss bridge with a marine area of 1,618 m and a center span of 440 m
  • This 2,933 m bridge connects the central breakwater landfill and Koto-City Wakasu, straddling the Tokyo Port Third Seaway.
  • World's largest-scale continuous truss bridge with a marine area of 1,618 m and a center span of 440 m

Tokyo Gate Bridge erection location

erection location (between the central breakwater landfill and Koto-City Wakasu)

A 12% cost reduction is prospected for Tokyo Gate Bridge.

  • BHS steel for bridges is highly strong and tough and has excellent weldability and cold formability when compared to conventional rolled steel for welded structures (JIS G 3106 SM570, etc.).
  • For Tokyo Gate Bridge, it is prospected that the weight of steel is reduced 3%; and the total cost, 12% (announced by MLIT).
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Erection status using a floating crane (FC)

BHS steel is configured from two levels of steel strength standards, namely BHS500(Yield strength 500 N/mm2)and BHS700(Yield strength 700 N/mm2), which deliver greatly increased Yield strength when compared with the yield point of conventional steel at 420-460 N/mm2 (JIS G 3106 SM570). Using BHS500 also allows for economical design.

When manufacturing BHS steel, we took advantage of our unique next-generation controlled-cooling process, known as "CLC-μ"*1. Using this technology allows us to manufacture high-quality, high-performance steel products, which show higher strength than conventional steel and for which preheating during welding can be omitted or reduced.

Especially now, on-site welding is performed in the local yard of the large-scale, all-welded huge truss bridge*2, and therefore it is evaluated that using BHS500, which enables the omission of preheating, has a great effect on the promotion of streamlining manufacturing*3.

  1. CLC stands for "Continuous Online Control Process" and has the following three meanings:
    1. It refers to a "Metallurgically Universal" process using adjustable cooling, and MU is read as "μ."
    2. The symbol "μ" (micro) reminds us of microstructure control or grain diameter.
    3. The symbol "μ" also invokes the image of words such as: ultra, ultimate, unrivaled, universal, uniform, unique, unlimited, etc.
  2. This structure is built by welding all the panel points of the chord members, the major components; it does not use bolts.
  3. Welding procedure test results by Kawada Industries, Inc. and others

Inclusion in JIS standards

BHS steel is expected to also have economic effects on general road bridges and railway bridges, and therefore, based on the example of the "Tokyo Gate Bridge", this steel JIS-established in November 20, 2008 as "JIS G 3140 Higher-yield strength steel plates for bridges (SBHS)."

Overview of example

Nagata Bridge

  • Nagata Bridge
  • Four-span continuous bridge with an entire length of approx. 250 m

The higher yield-strength steel plates for bridges manufactured by Nippon Steel, "SBHS" (Steel for Bridge High-performance Structures), were adopted for the Nagata Bridge, which was suspended over the Tama River, connecting Fussa and Akiruno cities in Tokyo (ordered by the Tokyo Metropolitan Government Bureau of Construction). The total weight of the steel used is approximately 600 tons. The Nagata Bridge is the bridge for which SBHS was first adopted after it was established as a JIS steel.

Adopting SBHS for Nagata Bridge

The "Nagata Bridge", which is currently being re-constructed, utilizes Japan's first bridge form, in which the lower flange and web of a conventional PC box girder bridge are configured as a space truss structure. It is a large-scale bridge with four-span continuous and an entire length of approx. 250 m.

Due to the pipe truss structure, ultra-thick and on-site weldable steel is necessary along with cold formability. Therefore, SBHS500 steel with a maximum plate thickness of 67 mm (previously, 50 mm maximum), a toughened property of 200 J (toughness that's approx. four times higher than ordinary steel), and a yield strength of 500 N/mm2 are adopted, and the steel pipes are manufactured using highly cold forming with a bending radius set to five times the plate thickness (at least 15 times for ordinary steel).

According to the Nishi Tama Construction Office, Tokyo Metropolitan Government, the use of a complex truss system increased transparency, harmonized the structure with nature, and enabled the reduction of the cost through weight savings. Our SBHS500 has contributed to the realization of this "airy" and beautiful bridge.

Characteristics of SBHS

SBHS is highly strong and tough, and has excellent weldability and cold formability when compared to conventional rolled steel for welded structures.

The yield strength, which refers to the design strength in the structural design, is 10-20% higher than conventional steel. This allows for economical design that includes weight savings.

The increase of yield strength is realized using steel microstructure makeup technology by taking advantage of the controlled-cooling process-not through the addition of alloy, which inhibits weldability and formability. Therefore, SBHS is also excellent regarding weldability (preheating can be omitted or reduced during welding) and cold formability.

Overview of example

Akashi Kaikyo Bridge

  • Japan
  • Entire length of 3,911 m with a center span 1,991 m
  • Three-span, two-hinge stiffened truss suspension bridge

The Akashi Kaikyo Bridge forms part of the arterial highway that connects Honshu and Shikoku. This three-span, two-hinge stiffened truss suspension bridge is 3,911 m long with the world's longest center span of 1,991 m.

Besides the design conditions that the bridge is tolerable against the wind speed of approx. 80 m/sec during a storm and a magnitude 8.5 class earthquake, the design and construction of the substructure were executed such that it can bear a tidal current of 4.5 m/sec in very deep waters.

Features

Adoption of high tensile-strength steel for bridges

TNippon Steel delivered approx. 4,200 tons of HT690 and HT780 steel for the stiffening girders; this steel can decrease preheating temperatures--a world first.

Overview of cable work

For cable construction, the Prefabricated Parallel Wire Strand™ (PWS) construction method, developed in the 1960s, was adopted, and construction of the strands was completed in approx. five months.

The cables of this brides are huge, with a diameter of approximately 1.1 m and a total weight of approximately 50,500 tons, and use a newly developed high-strength wires with a tensile strength of 180kgf/mm2.

Overview of example

Second connecting bridge to Incheon International Airport (Incheon Bridge)

  • South Korea
  • Overall length: 21.38km (longest in South Korea, world's 7th longest)
  • Completed in October 2009 (construction commenced in June 2005)
  • Completed in October 2009 (construction commenced in June 2005)

This large-scale project constructed a second connecting bridge between Incheon International Airport (Yeongjong Island) and the Songdo Free Trade Zone (Incheon City).

Straight web-type steel sheet-piles with the world's highest tensile strength were used to prevent collisions with the bridge piers.

The straight web steel sheet-piles were used as cylindrical (cell) anti-collision structures to prevent vessels in the Incheon Bridge seaway (800 m center span) from accidentally colliding with the bridge piers.

These straight web steel sheet piles were joined into enormous cylinders, driven into the seabed to a specified depth, and then filled with earth and sand. The integrated combination of steel sheet pilings and earth and sand fill create structures to withstand external forces.

Nippon Steel & Sumitomo Metal received an order for approximately 16,000 tons of sheet steel piles among a total 18,000 tons of structural steel for 40 foundations in total, all of which was manufactured at the Yawata Steel Works, Rail & Shape Mill (Kitakyushu City, Fukuoka), where delivery was completed between October 2007 and March 2009.

Cylindrical (cell) anti-collision structures (reference image)
Cell structure diagram

Unique straight web-type steel sheet pile cell construction method drastically shortens construction time.

Starting in the design phase, we proposed a variety of solutions regarding steel products and structures that make the most of the characteristics of straight web-type steel sheet piles. We achieved improvements in procurement of steel products and the construction methods, as well as a reduction of the construction period, and also indirectly supported the solution of various problems at the construction site.

With the straight web-type steel sheet pile cell construction method used for this project, steel sheet piles are assembled in the cell form at a location that is minimally affected by waves, and then transported to the installation site to be driven in. Therefore, this method can greatly shorten the construction period, drastically shortening the time that marine traffic is affected.

Photo of construction in progress (source: Nippon Steel)

Unique straight web-type steel sheet pile cell construction method drastically shortens construction time.

Our straight web-type sheet-piles (specification s: YSP-FXL, YSP-FL) have the following superior features:

  • 1. Length of steel sheet-pile: Up to 38m (world's longest, Nippon Steel's previous longest was 25m)
  • 2. Maximum tensile strength: 5,880 kN/m (world's highest)
  • 3. Diverse variety of sizes
Straight web-type sheet piles used in the cell shell

Overview of example

Nhat Tan Bridge

  • VietNam
  • Length: 3,080m
  • Width: 35.6m
  • Height of tallest tower: 108.56m

Financed by STEP yen loans, this bridge is currently under construction to commemorate the 1,000th anniversary of Thang Long-Hanoi in October 2010. The bridge is also called the Japan-Vietnam Friendship Bridge. Of the overall 8,293m length, the 3,080m (width 35.6m) spanning the Red River that flows through Hanoi is currently under construction. This bridge will also connect southern Hanoi with the Airport area to the north.

Steel pipe sheet-pile well foundations contribute to cost reductions.

Since the piers had to be built in a river, the steel pipe sheet-piles temporarily installed as cofferdams were used for the actual foundations.

The formation of cylindrical well-shaped pile foundations yielded greater bending rigidity and vertical bearing capacity than with normal pile foundations, reducing the size of the foundations.

Photo provided by Sumitomo Mitsui Construction Co. Ltd.

Contributions to reduced total construction costs

Since the steel pipe sheet piles are driven in an occlusive cylindrical well-shape, allowing the cofferdam walls for the river water to also be used as actual foundations, they contributed to an overall reduction of construction costs by eliminating the need for temporary work.

Since mechanized construction can be performed in the same way as in normal piling construction, laborsaving and rapid construction is possible. Furthermore, it is possible to build highly reliable foundations even though construction is done at the water's edge.

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STRUCTURAL SHAPES (North America ver.)

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Titanium Products for Building Construction

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