Nail Plate Truss Use Increasing in Post & Beam

In an encouraging trend, we have seen an increase in nail plate truss use in post and beam non-residential construction in Japan. On a recent trip to Hokkaido, Tokyo based staff had the opportunity to visit two post beam buildings with a Japan Wood Truss Council (JWTC) member that uniquely incorporated exposed roof trusses in a church in Sapporo City and vocational school and Chitose City.

 

Catholic Macromania Church (Sapporo, Hokkaido)

The first project, the Catholic Macromania Church with a total floor area for the church of 499 m² was constructed using parallel cord trusses made with SPF dimension lumber divided into two sections for ease of transportation and then joined with bolts and installed on site to design a beautiful cathedral wood roof spanning 11.6 m for its parishioners.

http://www.jwtc.org/examples/case26/index.html

Chitose Aviation Academy (Chitose, Hokkaido)

The second project being the Chitose Aviation Academy, which is a large-scale wooden building with a floor area of 986 m². In order to construct this large vocational school, low pitched mono nail plate trusses were used and revealed to construct the school’s 25.8 m spanning roof – proudly display the warmth and beauty of Canadian wood for students to see.

http://www.jwtc.org/examples/case27/index.html

Both these post and beam buildings were designed and constructed by Arch Vision 21 Inc. Based in Chitose, the company designs and builds residential and commercial buildings in the region. COFI has been working with this company for more than ten years promoting SPF dimension lumber and truss use in post and beam construction, and it is great to see them increasing the number and different types of non-residential buildings in the region.

COFI Japan Renews JAS ROCB Status

Dated March 2nd, 2020, Canada Wood/COFI(Council of Forest Industries) Japan renewed our status as a Registered Overseas Certifying Body (ROCB) under the Japanese Agricultural Standard (JAS) accreditation system supervised by the Ministry of Agriculture, Forestry and Fisheries (MAFF).  This gives COFI QC Division the ability to certify sawmills under the JAS system.  The current JAS system adopts ISO 17065 accreditation scheme, which requires voluminous paperwork.

 

 

Dating back to 1987, COFI has been recognized by the Japanese government as the first foreign testing organization (FTO) permitted to grade lumber outside of Japan to the JAS grade.  This provided a competitive advantage for Canadian industry.  Over time – in 1996, the NLGA system was granted mutual recognition by the Japanese government as a direct equivalent to the JAS grading system.  We could, therefore, ship NLGA marked lumber to Japan without stamping it with the JAS mark. However, it remained essential for us to retain access to the various standards committees that controlled and dictated the rules writing for wood products in Japan and as such JAS ROCB accreditation remains a vital credential allowing us to defend against market access challenges. To maintain this influence, we decided to retain our JAS certification accreditation.

Every four years, we need to reapply to keep our JAS certification active. Since this JAS certification in effect allows Canada Wood/COFI to conduct activities that are the responsibility of the Japanese government under licence they want to do their due diligence.

Corona Virus Japan Update

As of late March, Japan had a total of 1,905 cases of the Corona Virus – including 712 cases from the Diamond Princess cruise liner. The nation recorded 53 related deaths thus far. Currently, there are 15 clusters of patients nationwide: with concentrations in Osaka, Hokkaido, Aichi and Tokyo. While new cases appear daily, cases have not reportedly surged thanks to widespread adherence to social distancing and the use of precautionary measures. Prime Minister Abe has not yet called for a State of Emergency with containment measures appearing to be effective. Japan’s schools remain closed, as do major sporting and entertainment venues. Employers nationwide have widely employed telework and flex time measures since early March.

 

The economic impacts are only starting to be felt, but they are expected to be severe. In February, imports from China plunged 47% as factory shipments dried up. By Mid March, the Nikkei 225 Stock Index fell 30% from 24,000 to the 17,000 level since the beginning of the year. Excluding toilet paper, consumer confidence has plunged as has tourism. Japan is now thought to be in a recession. Supplementary budgets are being tapped to provide emergency medical services, and the government is preparing a new spending package to mitigate the expected downturn. Elements being considered include a reduction in the consumption tax, tax relief for at-risk families and financial assistance to pay utility bills. The Bank of Japan has also taken steps to increase liquidity and boost asset purchases; however, with a negative 0.1% lending rate, the BOJ effectively has no further room to lower interest rates without impairing the profitability of the financial sector. The Japan Seatbelt Manufacturers Association has issued an advisory to “strap on your seatbelts as this wild ride is just getting started”!

Infographic: Popularity of 2×4 Housing Increasing in Japan

 

According to a Japanese Government Cabinet Office survey conducted in October 2019, the popularity of 2×4 housing continues to gain traction among younger generations in Japan. The survey first reconfirms that the popularity of wooden housing remains strong, with approximately ¾ of survey respondents preferring to live in wooden housing, with the balance preferring non-wood alternatives. When asked which type of home they would like to purchase in the future, an average of 47.6% selected traditional Japanese style post and beam housing, 26% chosen 2×4 and 23.7% selected non-wood.

 

Interestingly, this Cabinet Office survey a rising preference for 2×4 versus post and beam housing over time. Preference for post and beam housing fell from 72.5% in 1989 to the 60% range in 1996, to the 50% range in 2011, to 47.6% today. Conversely, the preference for 2×4 homes increased from 9.4% in 1989 to its current 26%. Breaking the results down demographically, the popularity of 2×4 housing is strongest among younger generations. Two by four housing is the preferred choice among 37.8% of the 18-29 year-old segment; 34.2% among 30 to 39 segment; 33.9% among 40 to 49; 38.2% among 50 to 59; 25% among 60-69; and 9.5% among 70 years plus. Favorable perceptions of fire and seismic resistive performance of 2×4 housing are cited as reasons supporting these shifting preferences.

Removing Barriers for NLT Use in Japan

COFI has been working with the Japan 2×4 Home Builder’s Association to facilitate the spread of large-scale wooden buildings using Nail-Laminated Timber (NLT) in horizontal diaphragms such as roof and floor structures.  This is part of our Canada Wood Market Access technical projects for Fiscal 2019-2020.  One of the goals for this fiscal year was to obtain ministerial approvals for 1-hour quasi fire resistive floor structure and 30-minute quasi-fire resistive structure.  Another objective of the project was to seek a voluntary evaluation from an MLIT1)-designated third party performance evaluation body.

 

Both the 1-hour and the 30-minute quasi fire testing were successfully completed at the laboratories of Centre for Better Living (floor) and Japan Testing Centre for Construction Materials (roof).  We are at the final stage of obtaining the approvals as we have submitted the approval application to MLIT after the series of the evaluation committee judgements.  With the 2019 revision to the Building Standard Law and the MLIT approvals for quasi fire resistive approvals, visually exposed NLT will be able to be structural elements in the large-scale buildings that requires fire resistive performance.

 

As for the structural performance, NLT with butt joints requires a solution to verify how inferior such NLTs are to the NLTs without butt joints. NLT with butt joints comprise of dimension lumber pieces lined up sequentially lengthwise to achieve large spans.  COFI and the Japan 2×4 Home Builder’s Association jointly worked for obtaining a structural evaluation certificate from HOWTEC2), one of the MLIT-designated performance evaluation bodies.  Under the guidance from the evaluation committee members, we conducted bending tests with butt-joints at the Gunma Prefectural Forestry Laboratory from September through December 2019.  These were the 4-point loading bending test to 2×12 and 2×8 Canadian SPF.  After collecting the data, we confirmed if our numerical modelling works accurately on the rotational rigidity at the butt joint.

In addition to the bending test mentioned above, we also conducted the creep test to the NLT specimens to confirm the bending deformation over a long duration of time (1 month).  The creep test set-up has been located at the FRMO (Forest Research and Management Organization) laboratory in Tsukuba City. All NLT test work is expected to be completed by the end of this fiscal year.