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Japan’s First All-Timber Fire-Resistant High-Rise Building Construction Technologies

Start of Japan’s first all-timber fire-resistant high-rise building construction (the OY Project)

A training facility aimed at creating a new corporate culture by increasing wellness and comfort while encouraging free and open communication
To help facilitate the sustainable growth of the Obayashi Group, Obayashi Corporation has started constructing Japan’s first all-timber fire-resistant high-rise building as a next-generation training facility. This kind of building, which features all wood structural members (columns, beams, floors, and walls) is unique from a world-wide perspective as well.

A training facility that creates a corporate culture

The concept of our next-generation training facility is to create new innovation and a corporate culture by encouraging free and open communication. To achieve this concept, we decided to construct Japan’s first all-timber fire-resistant high-rise building to both reduce CO2 and facilitate CO2 fixation. Our plan is for the building’s wooden space to provide a relaxing, humidity-controlling effect. The building’s design and underlying technologies, which incorporate natural elements that include wind, lighting, and fragrances, are also intended to increase the wellness and comfort of users, thereby improving the training effects. By associating WellnessBOX—the smart building management system developed by our company—with users' vital data, we also hope to provide a more comfortable training and accommodation environment.
In addition, by minimizing the building’s outer load, actively utilizing natural energy, and introducing many optimal environmental technologies based on thorough consideration of the building’s utilization plan and methods, we have achieved a ZEB Ready (Net Zero Energy Building Ready) design for the building, ensuring that it will consume less than half the energy of general buildings. Furthermore, given the track record of the Obayashi Corporation Technology Research Institute (Kiyose City, Tokyo) main building Techno-Station, we are trying to obtain WELL and LEED Certification, standards for evaluating building environments and indoor environments for wellness.
To construct our all-timber fire-resistant high-rise building, we are applying Obayashi Corporation’s fire-resistant wood technology O・mega Wood (FR) to the building's structural members. In particular, the columns at the 1st floor are fire-resistant for three hours, which is first of its kind in Japan.
To build an all-timber mid- and high-rise building with the same span length as a reinforced concrete building, one issue was that the beam-column joints have to possess high rigidity and strength. To ensure on-site ease of construction while resolving the above issue, we developed a new method for unifying columns and beams: rigid joint units without steel connection components. To achieve high rigidity, resistance, and toughness, we are using technologies that include LVL with high-strength and stability for the columns and beams as well as the GIR joints and newly developed wood joint panels, which increase the strength via insertion, for the joints. In addition, our approach achieves high workability through off-site prefabrication of the structural units. Our training facility also has extremely high aseismic performance as a result of incorporating a seismic-isolation structure. In addition, the floors of the accommodation rooms use a newly developed soundproof CLT flooring material to help promote the spread of wooden buildings.

Rigid joint units without steel connection components
Configuration of a dry soundproof CLT floor

Overview of our next-generation training facility

Construction site 2-22, 23 Bentendori, Naka-ku, Yokohama, Kanagawa (lot area: 563.28 m²)
Construction period March 2020 to March 2022 (24 months, including the time necessary to demolish existing buildings)
Total area 3,620 m²
Number of floors One basement floor and 11 above ground floors
Structure All-timber seismic-isolation structure (fire-resistant building)

Laminated Veneer Lumber. Laminated veneer material made by gluing together thinly sliced layers of veneer lined up with the wood fiber pointing in the same direction.

A method of joining wood together with glue and connecting rods.

Cross Laminated Timber. Thick panels made by gluing together layers of lumber—or laminas—oriented perpendicularly to each other.

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