Corporate / CSR

May 19, 2017

 

Takenaka Expands Users of Proprietary Wood Technology for Seismic Upgrades, Building Structural Components

Keywords: Corporate Environmental Technology 

Photo
Copyright 2017 Takenaka Corp. All Rights Reserved.

Due to deregulation and efforts to revitalize Japan's domestic forestry industry, the use of wood in buildings is drawing attention. Takenaka Corp., a leading Japanese construction company, is promoting the use of wood in buildings by providing its wood utilization technology to other companies. With permission from Smart Japan, a news site that provides the latest information on the conservation, storage and generation of electricity, we translated and print here an article on Takenaka's efforts, originally published on December 12, 2016.

Takenaka was an exhibitor at Eco-Products 2016 (December 8 to 10 at Tokyo Big Sight), one of the largest environmental exhibitions in Japan, where the company showcased many of its construction technologies utilizing wood. The company's seismic retrofit technology (T-FoRest) that utilizes wood was awarded the 13th Eco-Products Award by Japan's Ministry of Land, Infrastructure, Transport and Tourism. Takenaka has been using the technology mainly in its own facilities, but due to the increase of wood use for buildings in Japan, the company has recently concluded licensing agreements with construction companies. By allowing other companies to use its technology, Takenaka plans to promote the overall use of wood in construction.

At the exhibition, Takenaka displayed two technologies to improve the earthquake-resistance of buildings. The first one was "T-FoRest" that utilizes laminated veneer lumber (LVL), cross-laminated timber (CLT) and other engineered wood products. At the booth, the company introduced "T-FoRest Light," which uses wood in place of steel braces and earthquake-resistant wood walls, dubbed "T-FoRest Wall," to replace reinforced concrete walls.

Steel braces are regularly used in building openings as a seismic retrofitting method. T-FoRest Light replaces steel with engineered wood products having equivalent strength. Springs attached at the edge of engineered wood braces apply tension to secure the structural components. Thus, engineered wood bracing does not require the joining work that would be needed when using steel, such as welding and gluing.

The T-FoRest Wall, which uses CLT and LVL panels instead of seismic-resistant reinforced concrete walls, also has benefits in terms of construction. It takes half the time to put up compared to conventional reinforced concrete walls, as components can be carried onsite on wagons as separate CLT panels and assembled in place where reinforcement is necessary, by securing posts, joists and panels with special adhesives.

The T-FoRest Wall technology has been introduced at three construction sites, and consideration is under way for three more sites. So far it has been utilized only in buildings that Takenaka Corporation has designed and constructed, but Takenaka has now signed construction licensing agreements with three companies engaged in seismic retrofitting: Sho-Bond Corporation, Bond Engineering and Toho Earthtech. It plans to expand the application of T-FoRest Wall in seismic retrofitting, which can be done while the building is in use. The contracts stipulate the use of Takenaka's T-FoRest performance certification and patents related to the utilization of the technology. The technology is not limited to use in public or private buildings, but is limited to uses covered by the performance certification.

The second technology introduced at the booth is a fire-resistant engineered wood, dubbed "Moen-Wood," meaning incombustible wood in Japanese. The material is made of three layers: a load-bearing wood layer, incombustible layer made of mortar and wood, and combustible wood layer. It can be used as structural components including posts and beams. In a fire, the outer combustible layer becomes char, providing good thermal insulation and protecting the inner wood from being burned.

Photo
Copyright 2017 Takenaka Corp. All Rights Reserved.

The incombustible layer consists of alternating layers of mortar and engineered wood. Mortar absorbs heat to shut out flames and protects the core load-bearing layer from flames. Even in a fire, the temperature of the load-bearing component carrying the building load is kept below 260 degrees Celsius. The Moen-Wood has been certified by the Minister of Land, Infrastructure and Transportation as a one-hour fire-resistant structural building material under Japan's Building Standards Act. Projects using Moen-Wood construction technology do not require special approvals to build, so they follow the same process as with other structures such as reinforced concrete and steel, if the spans of up to about nine meters between posts. Moen-Wood had been introduced in six projects at the time of the original article.

Takaneka intends to enter into licensing agreements for manufacturing and sales of Moen-Wood with other companies. Agreements were expected with three manufacturers by the end of 2017: Saito Wood Industry, Toju Corporation and Meiken Lamwood Corporation. The technology is only applicable to construction projects contracted by national institutions and local governments at the moment, but Takenaka plans to expand the scope of applications in the future.

Source: Smart Japan (in Japanese)

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