Japan Steel Tower Co., Ltd.

Japan Steel Tower Co., Ltd. (日本鉄塔工業株式会社), operating within the JST Group and often branded as JST, is a Japanese steel-structure engineering company headquartered at Shinsuna Plaza in Koto-ku, Tokyo. It traces its origins to May 1922, when a factory equipped with Japan's first hot-dip galvanizing bath for tower and pole manufacturing was completed in Wakamatsu, Fukuoka Prefecture (now Wakamatsu-ku, Kitakyushu). The plant was initially a works of Hattori Seisakusho, a Tokyo-based railway rolling-stock company, and was later separated and incorporated as Wakamatsu Hattori Seisakusho; the group regards the completion of the Wakamatsu plant as its founding and its first plant manager, Yujiro Arita, as its founder. The company describes itself as a top company in steel structures, handling transmission and communication towers, bridges, and special steel structures such as the Tokyo Skytree. Its business spans design, fabrication, hot-dip galvanizing, maintenance, life-extension and technology development, providing integrated services that contribute to the development of core social infrastructure. Its tower business pioneered the world's first hollow steel-pipe tower and has contributed to the advancement of power and communication infrastructure. Its hot-dip galvanizing business dates to its founding as Japan's first tower maker equipped with a galvanizing bath. Its bridge business, with a history of more than 50 years, has been involved in many of Japan's representative long-span steel bridges, including the Kurushima-Kaikyo Bridge. Its special steel structure business has fabricated complex and unusual structures such as the Tokyo Skytree, the Tetsujin 28-go monument and special steel frames for Shibuya Hikarie. The company also operates a maintenance and life-extension business for towers, bridges and radio masts, developing proprietary advanced equipment and methods, and a design, analysis and experiment function supporting quality improvement and technical strength. Notable proprietary technologies include the low-noise SJS and SJS-H methods for removing bridge expansion joints using a proprietary wire saw, ultrasonic diagnosis of the inner surfaces of hollow steel-pipe towers, and member replacement methods. It also developed the NT-DEC bolt in 2009. Japan Steel Tower is a private company within the JST Group, whose website covers four companies: Wakamiya Co., Ltd., JST Corporation, Japan Steel Tower Co., Ltd., and Japan Steel Tower Omori Works Co., Ltd. The group is headquartered at Shinsuna Plaza, 1-6-27 Shinsuna, Koto-ku, Tokyo. It remains active in power and communication infrastructure, bridges, special steel structures and solar power mounting frames, and pursues CSR and environmental activities including compliance, environmental preservation and community contribution.

The origins of Japan Steel Tower lie in the completion, in May 1922 (Taisho 11), of a factory in Wakamatsu, Fukuoka Prefecture (now Wakamatsu-ku, Kitakyushu), equipped with Japan's first hot-dip galvanizing bath for manufacturing towers and poles. The plant was initially established as a works of Hattori Seisakusho Co., Ltd., a company that operated a railway rolling-stock business in Ikebukuro, Tokyo. Hattori Seisakusho had noticed growing electricity demand and developed a small triangular-section steel pole (the 'triangular steel pole') to replace the wooden utility poles that were then dominant. To manufacture and sell it on a large scale, a dedicated factory was built on the site of a steelmaker producing the 60-degree angle steel used as material. The Wakamatsu Works was completed in May 1922 with a state-of-the-art hot-dip galvanizing bath, the first tower and pole factory of its kind in Japan. The group regards the completion of the Wakamatsu Works as its founding, and Yujiro Arita, who led the construction as plant manager and contributed greatly to the subsequent development of the business, as the founder of the JST Group. In 1938 (Showa 13), the Wakamatsu Works took over all rights and obligations, including plant facilities and employees, from Hattori Seisakusho and became independent as Wakamatsu Hattori Seisakusho Co., Ltd. Its head office was in Nihonbashi-ku, Tokyo (now Chuo-ku, Tokyo), with capital of one million yen. In 1952 (Showa 27), the Tokyo Works of Osaka Seiki Kogyo Co., Ltd. (now ISK Co., Ltd.) was brought into the group as the Omori Works, and production of bolts and nuts for towers began. In January 1955 (Showa 30), a new Sunamachi Works was established in Minamisunamachi, Koto-ku, Tokyo (now Shinsuna, Koto-ku), to help rapidly develop transmission networks amid growing tower demand. In 1961 (Showa 36), the company received an order from Kyushu Electric Power Co., Inc. for Japan's first rectangular MC steel-pipe tower. This was the group's first steel-pipe tower and became the foundation of its later growth. (MC steel-pipe towers are towers with concrete filling inside the steel pipe; towers without concrete filling are called hollow steel-pipe towers, which the JST Group developed first in the world.) In the same year, the company changed its name to Japan Steel Tower Co., Ltd. (日本鉄塔工業株式会社). In 1963 (Showa 38), it entered the bridge business. In 1965 (Showa 40), it developed the hollow steel-pipe tower and forged flange joints. In 1984 (Showa 59), it established a bridge factory to respond to the increasing span of bridges. In 1990 (Heisei 2), it participated in ultra-large towers such as strait-crossing towers. In 1993 (Heisei 5), the high-rise office building Shinsuna Plaza (Koto-ku, Tokyo) was completed. In 2004 (Heisei 16), it entered the tower maintenance business. In 2009 (Heisei 21), it developed NT-DEC® bolts and participated in the fabrication of the Tetsujin 28-go monument and the Tokyo Skytree. In 2013 (Heisei 25), it entered the solar power generation mounting-frame business. In 2016 (Heisei 28), it received the Kitakyushu City Work-Life Balance Award. The company's own history page also lists a parallel chronology: founding in 1922; company name change and order for Japan's first MC steel-pipe tower in 1961; entry into the bridge business in 1963; development of forged flange joints in 1966; response to larger bridges in 1984; response to ultra-large towers in 1990-1994; development of the NT steel-structure life-extension system in 2004; and fabrication of the Tetsujin 28-go monument and Tokyo Skytree in 2009-2010. Today the company operates within the JST Group, whose website covers Wakamiya Co., Ltd., JST Corporation, Japan Steel Tower Co., Ltd., and Japan Steel Tower Omori Works Co., Ltd., and it continues to serve power, communication, bridge and special steel structure markets from its Tokyo base.

• 2016

  Received the Kitakyushu City Work-Life Balance Award.

• 2013

  Entered the solar power generation mounting-frame business.

• 2009

  Developed NT-DEC® bolts; participated in fabrication of the Tetsujin 28-go monument and Tokyo Skytree.

• 2004

  Entered the tower maintenance business and developed the NT steel-structure life-extension system.

• 1993

  Shinsuna Plaza high-rise office building completed in Koto-ku, Tokyo.

• 1990

  Participated in ultra-large towers such as strait-crossing towers.

• 1984

  Established a bridge factory to respond to longer bridge spans.

• 1966

  Developed forged flange joints (per company chronology).

• 1965

  Developed the hollow steel-pipe tower and forged flange joints.

• 1963

  Entered the bridge business.

• 1961

  Received Japan's first order for a rectangular MC steel-pipe tower from Kyushu Electric Power; changed company name to Japan Steel Tower Co., Ltd.

• 1955

  Established the Sunamachi Works in Koto-ku, Tokyo.

• 1952

  Brought Osaka Seiki Kogyo's Tokyo Works into the group as Omori Works and began making tower bolts and nuts.

• 1938

  Wakamatsu Works separated from Hattori Seisakusho and became independent as Wakamatsu Hattori Seisakusho Co., Ltd.

• 1922

  Founded in May in Wakamatsu, Fukuoka Prefecture, as Japan's first tower and pole factory equipped with a hot-dip galvanizing bath.

A top company in steel structures providing integrated design, fabrication, galvanizing, maintenance and life-extension services for power, communication, bridge and special steel infrastructure.

• Transmission and communication towers

  Steel towers for power and communication infrastructure, including hollow steel-pipe towers pioneered by the company.

• Steel bridges

  Long-span steel bridges including the Kurushima-Kaikyo Bridge, with a history of more than 50 years.

• Special steel structures

  Complex and unusual steel structures such as the Tokyo Skytree, the Tetsujin 28-go monument and Shibuya Hikarie special steel frames.

• Hot-dip galvanizing

  High-quality hot-dip galvanizing services from Japan's first tower maker equipped with a galvanizing bath.

• Solar power mounting frames

  Mounting frames for solar power generation, a business entered in 2013.

• Maintenance and life-extension services

  Maintenance and life-extension for towers, bridges and radio masts using proprietary equipment and methods.

• NT-DEC® bolts

  Bolts developed in 2009 for steel structures.

1. 1日本鉄塔工業株式会社 -jsteam.jp
2. 2沿革 - JST株式会社jsteam.jp
3. 3サイトについて - JST株式会社jsteam.jp
4. 4企業活動規範と環境・ＣＳＲ - JST株式会社jsteam.jp
5. 5Japan Steel Tower Co., Ltd. (Japan) - Wikidatawikidata.org