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Development of wood structural elements for fire resistant buildings

Hirokazu Ohashi (Research and Development Institute, Takenaka Corporation, Chiba, Japan)
Shinya Igarashi (Head Office, Takenaka Corporation, Tokyo, Japan)
Tsutomu Nagaoka (Research and Development Institute, Takenaka Corporation, Chiba, Japan)

Journal of Structural Fire Engineering

ISSN: 2040-2317

Article publication date: 17 July 2017

Issue publication date: 17 May 2018

348

Abstract

Purpose

As forestry contributes to the reduction of greenhouse gases by CO2 fixation, in recent years, use of wood in buildings has attracted all over the world more attention. However, construction of large wood structures is almost inexistent within urban areas in Japan. This is due to the Japanese law on fire protection of wood buildings in cities, which is considered very strict with severe requirements. This paper aims to present a research work relative to the development of one-hour fire-resistant wood structural elements for buildings in cities. The developed elements are composed of three layers made of laminated timber.

Design/methodology/approach

These wood structural elements, made of glued laminated timber with self-charring-stop, have sufficient fire resistance during and after a fire and comply with the strict Japanese standard for wood structural elements, which stipulates that such elements have to withstand the whole dead-load of concerned buildings after fire. To comply with such requirements, new elements of glued laminated timber with self-charring-stop layer were developed, and their performance was confirmed. Several fire-resistant tests conducted on columns, beams, column-beam joints, connections between beams and walls and beams with holes were carried out.

Findings

All tests proved that the elements have sufficient fire resistance. No damage was found out at the load-bearing part of the elements after testing. As the developed elements have two layers protecting the load-bearing part, the temperature in the load-bearing part could be retained below 260°C (carbonization temperature) and provide the elements with a sufficient fire resistance for 1 h.

Practical implications

These wood structural elements have already been applied in six projects, where large-size wooden buildings were constructed in urban areas in Japan.

Originality/value

The proposed structural elements use a novel technique. Every wooden element is composed of three layers made of glued laminated timber. The elements have a typical performance of self-charring-stop after fire without need for water of firefighters. More technologies related to these elements, including column-beam joints and beams with holes and effect of crack, were also developed to design and construct safe wooden buildings.

Keywords

Acknowledgements

This study has been funded by NEDO (New Energy and Industrial Technology Development Organization), MLIT (Ministry of Land, Infrastructure and Transport and MAFF (Ministry of Agriculture, Forestry and Fisheries).

Citation

Ohashi, H., Igarashi, S. and Nagaoka, T. (2018), "Development of wood structural elements for fire resistant buildings", Journal of Structural Fire Engineering, Vol. 9 No. 2, pp. 126-137. https://doi.org/10.1108/JSFE-11-2016-0019

Publisher

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Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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