The Forestry Agency recently announced that the percentage of wood construction (based on floor area) among public buildings that started construction in fiscal 2015 (April 2015 to March 2016) was estimated to be 11.7% (1.3 point increase compared to the previous year). Also the percentage of wood construction among low-rise (3 stories or less), public buildings that are seen as actively moving ahead with the conversion to wood construction following the “Basic Policy for the Promotion of Wood Utilization in Public Buildings” was 26% (2.8 point increase). The percentage of wood construction among all the buildings in fiscal 2015 was 41.8% (1.5 point increase). Looking at the percentage of wood construction among public buildings in fiscal 2015 based on prefectures, the highest percentage was 38.6% in Akita Prefecture followed by 30.8% in Iwate, 29.7% in Miyazaki, 27.9% in Yamanashi, and 27.6% in Yamagata. The lowest percentage was in Okinawa with 0.2% followed by Tokyo with 2.8% and Hyogo with 4.8%. The percentages for other prefectures were 18.9% in Gifu, 18.7% in Mie, 15.8% in Nagano, 12.7% in Aichi, 9.3% in Shizuoka, and 6% in Osaka. Among public buildings of three-stories or less, the percentages were 55.3% in Akita, 47.8% in Tottori, 47.6% in Miyazaki, 43.6% in Oita, 43.2% in Yamagata, and 42.3% in Yamanashi.
A cross sectional study group concerned with the expansion in the use of lumber in civil engineering recently submitted a proposal titled “Aiming for an Ease in Global Warming, Revitalization of the Forest Industry, and Sustainable Construction Industry- Towards an Expansion in the Use of Lumber in the Field of Civil Engineering” to the Forestry Agency and the Ministry of Land, Infrastructure, Transport and Tourism. The study group was established with the cooperation of the Japan Society of Civil Engineers, the Japanese Forest Society, and the Japan Wood Research Society, and the group includes a number of supporting associations. With a necessary aim to make use of Japan’s abundant forest resources in the field of civil engineering and to strengthen national resilience and countermeasures against global warming and to revitalize the forest industry, the following 5 items were proposed. The proposals were: 1) ascertain the situation and amount of lumber to be used in the field of civil engineering, 2) create opportunities for use and support technological developments in the expansion of lumber use, 3) promote lumber use that is related to a reduction in the environmental impact in the field of civil engineering, 4) promote cooperation between business, government, and academic institutions to lead to the expansion in lumber use, and 5) cooperate in raising awareness of technological use and personnel development related to lumber and the environment. Within the second proposed item, the amount of lumber used was pointed out to be actually increasing due to the development of ground improvement methods using logs and plywood used for concrete molding. Promotion of continuous technological developments and establishing opportunities to use new technology were brought to attention.
On April 6, an explanatory meeting and on-site tour were held for the head office building of Flavor Life Co., Ltd. located in Kokubunji, the first seven-story, wooden hybrid, fire resistant building in Japan. The building stands in a business district about a 5-minute walk from JR Kokubunji Station outside of the Tokyo Metropolitan area, and it is on a site of 180.8 m² with a construction area of 103.52 m² and a total floor area of 606.31 m². The building structure is all steel framed, and the 4th to 7th floors are a wooden hybrid construction. The wooden hybrid construction of the 4th to 7th floors was designed with a “Popular Model” that was added to improve the usual model of wooden hybrid construction. A “non-bracket” construction method was used in the joining connections of the steel frame, and a simplification was planned for the manufacturing of the laminated lumber, which has a high level of difficulty. Wooden hybrid laminated lumber was used only in the parts that appear outwardly, and in other areas, cost reductions were also carried out such as using general fire-resistant coating material. The Tsukuba Research Institute of Sumitomo forestry Co., Ltd. conducted the fire-resistant performance verification tests three times, and the results were carefully examined. The wooden hybrid laminated lumber with the steel frame in the inner core was manufactured by Chuto Co., Ltd. (Nomi City, Ishikawa Prefecture), and the end parts of the laminated lumber for the joining connections were lined with reinforced gypsum boards. The building was planned following the wishes of the customer who has a career in aroma therapy.