Oregon and southwest Washington are poised as a manufacturing hub for the emerging Cross Laminated Timber (CLT) market in the United States. The region is bountiful with luscious forestland, a large percentage of which is designated as working forests. Thirty million acres of forest span across Oregon alone. As a value add product that has environmental and social co-benefits, CLT is economically competitive as a structural framing product for multi-story, even high-rise building construction: a market previously dominated by concrete and steel.
The research and outreach activities performed as part of this 2015-2017 study have played a vital role in continuing the advancement of the CLT market in Oregon & SW Washington. Eager regional stakeholders see CLT and other mass timber panel products as forest products capable of providing economic benefit to communities within our region that had grown around forest product industries.
The goal of this study was to update life-cycle assessment (LCA) data associated with laminated veneer lumber (LVL) production in the Pacific Northwest (PNW) region of the United States from cradle-to-gate mill output. The authors collected primary mill data from LVL production facilities per Consortium on Research for Renewable Industrial Materials (CORRIM) Research Guidelines. Comparative assertions were not a goal of this study.
The goal of the present study was to develop life-cycle impact assessment (LCIA) data associated with gate-to-gate laminated veneer lumber (LVL) production in the southeast (SE) region of the U.S. with the ultimate aim of constructing an updated cradle-to-gate mill output life-cycle assessment (LCA). The authors collected primary (survey) mill data from LVL production facilities per Consortium on Research for Renewable Industrial Materials (CORRIM) Research Guidelines. Comparative assertions were not a goal of the present study.
This project identifies drivers for, and barriers to, the increased use of prefabricated timber building (PTB) systems in Class 2 to 9 commercial buildings, such as apartments, hotels, office buildings and schools.
PTB systems in Australia are in a formative stage and yet to achieve broad acceptance in the marketplace as a conventional method of building.
Opportunities for PTB systems can use timber’s well-established benefits such as high strength-to-weight ratio; design and construction flexibility; general environmental credentials including carbon sequestration; and prefabrication’s suitability for use on brown-field, restricted access and difficult sites and developments. In addition legislative constraints have now been largely removed (e.g. through changes to the 2016 National Construction Code).
An increase in large scale mid-rise prefabricated buildings, and with the increasing nationalisation and internationalisation of the top tier building companies, suggests market acceptance will grow as PTB buildings are seen as ‘normal’.
Timber-steel hybrid systems utilize timber as main construction material, but also take advantage of the ductility and stiffness that steel provides. For a novel hybrid system to gain recognition, experimental data must be supported by numerical analysis to predict its structural performance. “Finding the Forest Through the Trees” (FFTT) is one proposal for a timber-steel hybrid system using mass-timber panels as shear walls and floor slabs connected with steel header beams. This thesis presents research to evaluate the seismic performance of the FFTT hybrid system using experimental methods, numerical modeling, and reliability analysis. The FFTT system was investigated on two levels: i) component design, and ii) system design. On the component level, the strength, stiffness, ductility, and failure mechanisms of the two key connections were evaluated experimentally. CLT (Cross Laminated Timber) wall to steel beam connection tests results demonstrated that appropriate connection layouts can lead to the desired failure mechanism while avoiding crushing of the mass-timber panels. For the hold-down connection, a modified HSK (Holz-Stahl-Komposit) assembly with high force and stiffness capacity together with ductile behaviour was proposed. On the system level, the seismic response of the FFTT system with different ductility values was investigated using nonlinear 2D and 3D models subjected to a number of ground motion acceleration records. The seismic reliability with various uncertainties was analysed in order to investigate the FFTT system from a performance based approach. Based on the results, an appropriate seismic force reduction factor specific to the FFTT system was proposed. Finally, a feasibility study confirmed the possibility of the practical application of this system. This thesis can serve as a precursor for developing design guidelines for tall wood-hybrid building systems in seismic regions.
Recent developments in novel engineered mass timber products and connection systems have created the possibility to design and construct tall timber-based buildings. This research presents the experiments conducted on the steel-wood connection as main energy dissipating part of a novel steel–timber hybrid system labelled Finding the Forest Through the Trees (FFTT). The performance was investigated using quasi-static monotonic and reversed cyclic tests. The influence of different steel beam profiles (wide flange I-sections and hollow rectangular sections), and the embedment approaches (partial and full embedment) was investigated. The test results demonstrated that appropriate connection layouts can lead to the desired failure mechanism while avoiding excessive crushing of the mass timber panels. The research can serve as a precursos for developing design guidelines for the FFTT systems as an option for tall wood-hybrid building systems in seismic regions.
Bosnia and Herzegovina is the most forested country in the Balkan area, and Sweden and Slovenia are two of the most densely forested countries in the European Union. Living habits differ considerably between these three countries, but the use of wood is very similar. This book grew out of the collaboration of three wood scientists with totally different backgrounds who met and discussed their common interest – wood. Based on the different experiences in each country, the idea was to try to find ways to increase the common knowledge base for the use of wood, achieving excellence in timber design research and education; the architect with a deep knowledge of culture based needs, the engineer with experience and knowledge of technological needs, and the practitioner who always has to find the final solution.
International Scientific Conference on Hardwood Processing
September 25-28, 2017, Lahti, Finland
Low-grade hardwood logs are the by-product of logging operations and, more frequently today, urban tree removals. The market prices for these logs is low, as is the value recovered from their logs when producing traditional forest products such as pallet parts, railroad ties, landscaping mulch, or chips for pulp. However, the emergence of cross-laminated timber (CLT) for building construction in North America may provide an additional and possibly a more valuable product market for low-grade, low-value hardwood logs. Using the RaySaw sawing and ROMI rough mill simulators and a digital databank of laser-scanned low-grade yellow-poplar (Liriodendron tulipifera) logs, we examine the yield-recovery potential for lumber used in the production of CLT.