Project contact is Mariapaola Riggio at Oregon State University
Earthquake engineers are focusing on performance-based design solutions that minimize damage, downtime, and dollars spent on repairs by designing buildings that have no residual drift or “leaning” after an event. The development of timber post-tensioned (PT), self-centering rocking shear walls addresses this high-performance demand. The system works by inserting unbonded steel rods or tendons into timber elements that are prestressed to provide a compressive force on the timber, which will pull the structure back into place after a strong horizontal action. But, because these systems are less than fifteen years old with just four real-world applications, little information is known regarding best practices and optimal methods for engineering design, construction and/or tensioning procedures, and long-term maintenance considerations. This project intends to contribute knowledge by testing both cross-laminated timber (CLT) and mass plywood panel (MPP) walls through testing of anchorage detailing, investigating tensioning procedures for construction, determining the contributions of creep on prestress loss over time, and comparing all laboratory test data to monitoring data from three of the four buildings in which this technology has been implemented, one of which is George W. Peavy Hall at Oregon State University. This will be accomplished by testing small- and full-scale specimens in the A.A. “Red” Emmerson Advanced Wood Products Laboratory, and small-scale specimens in an environmental chamber.
Project contact is Mark Fretz at the University of Oregon
University of Oregon and Oregon State University are collaborating through TallWood Design Institute (TDI) to upgrade aging, energy inefficient and seismically unprepared multifamily housing by developing a mass plywood (MPP) retrofit panel assembly that employs digital workflows and small diameter logs (down to 5") to create an economically viable energy/seismic retrofit model for the West Coast and beyond. The project has broad potential to support forested federal land management agencies and private forestry by proving a new market for small diameter logs.
Buckling Restrained Brace Frames (BRBF) are a proven and reliable method to provide an efficient lateral force resisting system for new and existing structures in earthquake prone regions. The fuse-type elements in this system facilitate stable energy dissipation at large load deformation levels. Currently, the new trend towards mass timber vertical...
Project contact is Kevin Van Den Wymelenberg at the University of Oregon
Our aim is to support the acceptance and increase market share of sustainable mass timber construction technologies such as Cross Laminated Timber (CLT), Mass Plywood Panel (MPP), Glue Laminated Timber (GLT), and Nail Laminated Timber (NLT), by lowering or eliminating barriers due to lack of acoustics data for mass timber construction assemblies. Currently, sustainable mass timber projects carry the cost of required acoustics testing, impairing their economic feasibility. With our new acoustics testing facility, testing supported by this grant will produce common acoustics data on the assemblies most in market demand. These data will be hosted in an online open-access database, supporting rapid growth in this industry. Increasingly specialized testing scenarios will be more easily accommodated, as this facility is located closer to USFS source materials and production facilities than currently operating facilities and is designed specifically for the specialized requirements of testing mass timber assemblies. Since sustainable mass timber technologies allow increased utilization of lower quality timber, and timber with insect damage, increasing the market share of mass timber will increase utilization of USFS timber, specifically that which might otherwise remain on-site unused. With removal of this type of timber, fire load will be lessened as well. Initial testing supported by this grant will include mass timber assemblies constructed with lower quality and smaller dimension timber.
Project contacts are Arijit Sinha, Andre Barbosa and Barbara Simpson at Oregon State University
The results of this proposal will provide guidance on efficient design and analysis strategies for wood building construction including rocking/post-tensioned and pivoting spines, a next-generation seismic force resisting system, for improved performance, safety, sustainability, and economy. The use of wood in tall buildings is limitied by strength and stiffness considerations. The use of CLT and MPP shear walls, supplemented by energy dissipators may be able to aleviate this problem. Several knowledge gaps exist in terms of the performance of mass timber lateral force resisting systems (LFRS), interconnectivity and compatibility between the modules and LFRS-to-gravity system, and potential hybridization of structural materials for the gravity system and LFRS. The recent 2017 two-story shake table test is the only full scale dynamic on rocking CLT LFRS with energy dissipators. Importantly, since MPP panels are also a recent addition in the mass timber industry, no experimental data exist regarding the self-centering performance of post-tensioned MPP wall panels.
Project contacts are Andre Barbosa and Arijit Sinha at Oregon State University
In order to facilitate adoption of new mass timber products into practice, physical testing is required to understand and predict structural behavior. While extensive testing has been conducted at Oregon State on basic engineering properties of mass plywood panels (MPP) and MPP-to-MPP connections, there exists no experimental data on connections between MPP and other timber members (e.g. glulam) or on composite behavior of MPP with a concrete topping. Previous testing on CLT concrete-composite systems looked at different CLT-to-concrete connection systems, with HBV shear connectors-steel plates partially embedded in the timber with epoxy resin- as a strong candidate in terms of strength and stiffness performance. This project will focus on exploring the performance of MPP-concrete composite systems with HBV connectors.
Wood-based mass-panels (WBMP) are emerging as an attractive construction product for large-scale residential and commercial construction. Australia is following the lead of Europe and North America with several recent projects being completed using predominately cross-laminated timber panels (CLT). These sawn timber-based panels offer some key advantages to the construction and sawmilling industry. However, veneer-based mass-panel (VBMP) systems could offer additional benefits including the more efficient use of the available forest resources to produce WBMPs that have equivalent to superior performance to CLT. Research to confirm the expected technical viability of veneer-based systems is required. VBMPs could provide a valuable contribution, alongside CLT, to the Australian timber products market.
Project contacts are Linda Zimmer and Cory Olsen at the University of Oregon
During the testing and fabrication of mass timber projects a natural byproduct inevitably occurs in the form of offcuts and cutouts. In the case of new mass timber structures, the engineered wood materials are typically fabricated and prepared off site, allowing for the majority of the leftover materials to be made into useful products at the same facility already ideally set up for further digital fabrication. While the thickness of many of the spare panelized elements under investigation/production at TDI might seem excessive for smaller scale elements, the digital design and production techniques already being used allow for a fine degree of precision commensurate with furniture joinery. We propose to experiment with designing and fabricating furniture scale components and furniture prototypes as a way to reclaim these otherwise unused timber products. This project captures off cuts and remaindered materials from structural testing at TDI in both CLT and MPP panels.
Our focus is the design and fabrication of freestanding furnishings (ex: stools, benches, tables, chairs) that will exploit the technologies available at the Emmerson Lab. We come at this with two perspectives: in the first, products could be made directly from the materials available; in the second, the output will act as a formwork or “jig” to facilitate construction of an entirely new prototype that could expand into additional material languages. In either case it is important to us to share digital files of prototypes as “open source” designs so that production facilities and design professionals can work together to reduce waste and/or use our designs as a springboard to customize their own pieces. In this way we address the stated program goals to expand and develop new products and building components and to foster markets for these. Our iterative approach to digital design and digital hybrids utilizes CNC/robotic fabrication and assembly and we will be testing our ideas in a design-build format.