Two of the major topics of interest to those designing taller and larger wood buildings are the susceptibility to differential movement and the likelihood of mass timber components drying slowly after they are wetted during construction. The Wood Innovation and Design Centre in Prince George, British Columbia provides a unique opportunity...
Mass timber is a generic name for a broad range of thick and heavy wood products such as cross-laminated timber (CLT), dowel-laminated timber (DLT), nail-laminated timber (NLT), and gluelaminated timber (GLT), among others. So far, vibration-controlled design methods have been developed mostly for CLT floors.
La construction massive en bois est un terme générique qui englobe une grande variété de produits du bois épais et lourds, notamment le bois lamellé-croisé (CLT), le bois lamellé-goujonné (DLT), le bois lamellé-cloué et le bois lamellé-collé (GLT). À ce jour, les méthodes de conception à vibrations contrôlées ont surtout été élaborées pour les planchers en CLT.
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.
This project aims to develop a commercially-viable wood adhesive for CLT that is free of formaldehyde and isocyanates and possesses good cure speed properties. Li and his team have successfully developed adhesives for plywood manufacturing using abundant, inexpensive and renewable soy flour. This adhesive mimics the superior bonding properties of mussel additive proteins. Emission of hazardous air pollutants from plywood plants that use this adhesive has dropped 50-90 percent. Development of such an adhesive for CLT would address increasingly stringent air quality regulations in many places such as Oregon and California. The existing chemical formulation for the plywood adhesive will be adapted for use in a cold-pressing process. Specimens will be created at the OSU wood composites labs and first tested to verify conformance with the PRG320 product standard for CLT. Specimens passing the tests will be sent to the Energy Studies in Buildings Laboratory at the University of Oregon, Portland, where they will be conditioned and tested to determine emission characteristics.
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.