Project contact is Rakesh Gupta at Oregon State University
The objective of this project is to determine the fire performance of connections made up of the custom cross-laminate timber (CLT) layups utilizing ponderosa pine from logs harvested in Western U.S. forest restoration programs and produced by regional CLT manufacturers. Tests will be performed using ASTM E119 standard protocol on the CLT Connections, with CLT manufactured by the manufacturer (Vaagen Brothers) located in the Northwestern U.S. Fire testing is required before manufacturers will consider using pine in CLT. The volume of pine in high fire danger areas in the Western U.S. is much greater than that of Douglas-fir and we believe that ponderosa pine lumber can be successfully utilized in CLT panels. This project builds on previous Wood Innovation grants: Muszynski et al., (2017), Gupta et al. (2018) and Riggio et al. (2018), first two aimed at determining the fire performance and the third on demonstration of a modular structure designed for custom cross-laminate timber (CLT) layups utilizing ponderosa pine from logs harvested in Western U.S. forest restoration programs. We estimate that as few as 100 proposed modular units a year will lead to utilization of approximately 33 MMBF of pine lumber, and will allow treatment of about 460 additional acres of threatened forestland. At this rate, the harvest and manufacture of the lumber required will retain or create about 9.2 jobs/MMBF, including 57 jobs created directly for the CLT manufacturing (as estimated by Beck Group).
Project contact is Karl Englund at Washington State University
Cross laminated timber (CLT) has energized the wood industry, not only throughout the US but also across the globe. Potential for lower construction costs and a sustainable building material has provided proponents of CLTs the fuel for their growth. However, to obtain lower feedstock costs and provide a truly sustainable building product the use of small diameter timber (SDT) and other lower quality woods is imperative, but not yet realized. The out-of-plane (OOP) defects such as twist, cup and bow commonly found in SDTs, make processing CLTs prohibitive due to the press load requirements that are needed to “flatten” these defects out and create intimate contact at the glue line. Due to this issue, many CLT manufacturers utilize high grade lumber, while SDT and other low value woods are culled out and not used. Our proposal will characterize the OOP defects commonly found in SDT Douglas-fir (DF) and ponderosa pine (PP) from the Inland Northwest, will develop a tool to calculate anticipated forces to compress out the OOP defects and evaluate the durability performance of a full-scale CLT panel that includes commonly rejected lumber from SDT due to presence of OOP defects. The tool developed in this project will provide the CLT industry with the know-how to determine the press loads required to make a panel from SDT feedstocks and how to lower these accumulated loads through reducing or changing the laminate cross-sectional dimensions. Results of this study will promote increased utilization of SDT lumber, currently rejected, for CLT production and will contribute to healthy forests and rural economic development.