Project contact is Pierre Blanchet at Université Laval
Several studies indicate that using wood from sustainable forest management in building construction both maintains or increases carbon sinks in the forest, temporarily captures carbon in buildings, and substitute more emitting materials or fuels. This strategy is interesting, but it is difficult to implement from a political point of view because its real benefits are complex to evaluate. There are several methods for evaluating the GHG impacts of a product over its entire life cycle, but there is no consensus on the method to be used to assess the impacts of GHGs from biogenic carbon - the carbon contained in living or dead biomass, such as wood. Many commonly used methods rely on simplifying assumptions that do not accurately assess the benefits that could accrue from increased use of wood products under construction. This PhD project will improve a promising method to evaluate the GHG impacts of biogenic carbon. Particular attention will be paid to the uncertainties of the method so that it provides all the information necessary for informed decision-making. The expected results could confirm that greater use of wood products reduces the environmental impacts of buildings, and that current methodologies are too simplified to inform policy making.
The objectives of this project are to develop a design methodology and to demonstrate performance for exterior bearing CLT walls used in buildings subject to force protection requirements. This methodology should be published by U.S. Army Corp of Enginee...
Project contacts are Xiping Wang at the Forest Products Laboratory, and Xinfeng Xie at Michigan Technological University
This project is expected to reveal if cross-laminated mixed hardwood and softwood species would have bonding properties similar to softwood CLT using commercial adhesives for timber laminating. The results will provide baseline data on adhesion properties of bonding mixed northern wood species.
Structural engineered woods require the use of previously evaluated structural adhesives in accordance with a variety of standard methods (ASTM D2559, ASTM D7247, CSA O112.9, CSA O112.10, CSA O177, etc.). The basic assumption is that a bonded engineered wood product will have a performance equivalent to, or better than, the non-bonded product it replaces, regardless of the conditions of use (dry, wet, fire, etc.). Nevertheless, the results of cross-laminated wood (CLT) fire tests have shown that the requirements currently imposed on adhesives do not allow to limit lamellae detachment when CLT is exposed to fire. Traditionally, this behavior is not observed for glulam. It is essential to review the classification and performance criteria imposed on adhesives by submitting them to the various tests currently standardized. The analysis of the results may also be used to develop a new test method for adhesives exposed to high temperatures, depending on the anticipated use of the engineered wood product.
Project contact is Christopher Higgins at Oregon State University
This project will optimize the strength, stiffness, vibration characteristics, acoustic qualities and fire resistance of cross-laminated floor systems utilizing a composite concrete and cross-laminated timber product. This project includes development, testing and optimization of an economical shear connector (to connect the CLT panel to the concrete slab) that will be compared with existing screw and steel plate solutions. The resulting prototype floor system will be tested at full scale.
In many mass timber buildings, CLT or nail laminated timber (NLT) floors are designed with a concrete topping to improve acoustic separation, reduce vibration or act as a fire barrier. Little research has examined the fire behavior of these floor systems, but some preliminary tests involving LVL show that they may be able to meet three-hour fire resistance ratings, which could potentially open up the use of mass timber in Type I buildings, representing a large market opportunity. This project will test the behavior of composite floors under fire loading conditions considering the following parameters: shear connector type, mass timber panel types and thicknesses and concrete thicknesses. It will also test and validate an innovative fire research methodology using radiant panels.
Michigan State University (MSU) will develop a construction time and cost estimating tool for the use of cross laminated timber (CLT) in commercial building construction. This responds to a significant barrier to adopting such buildings among the architecture, engineering, and construction (AEC) industry, which has been reported since 2014. Despite broad agreement that first costs (and by extension time) and life cycle costs are an important facet of CLT buildings, over one third of architects were uncertain about this topic. Nine out of ten architects also listed costs and cost information as a significant barrier. This project will expand wood products markets by addressing this significant AEC industry barrier, and as a result, encourage more designers and constructors to specify CLT in their buildings. The project includes the development of a web-based predictive cost and time tool; this is quite common during the conceptual design stage, and as such, these tools exist for steels and concrete buildings, yet very little information exists for CLT. The team will also develop up to 20 CLT building case studies, with a focus on as-built costs, life cycle costs (building maintenance, energy, and carbon), construction time, and green building certification. These cases will be used to develop continuing education training modules for designers and constructors. Finally, in an attempt to motivate current students to become more knowledgeable about CLT, MSU will sponsor a 4- and 2-year CLT construction management competition. We expect these efforts to reach over 300 designers and constructors, and up to 75 AEC students.
Prior research showed that inward moisture diffusion from absorptive claddings such as brick veneer, stucco, or manufactured stone veneer can be significant in wood-frame walls. The inward migration of moisture is greatest when the cladding is heated by ...
Contact: C. Elizabeth Stokes, Mississippi State University, Juliet Tang, Forest Products Laboratory
Outcomes anticipated from the results of this project are biodegradation information for CLT products and an improved understanding of biodegradation differences between CLT products and comparable laminated and solid wood products. Results will benefit the emerging CLT industry and provide valuable information for market expansion into areas with high termite pressure.
Project contact is Arijit Sinha at Oregon State University
Constructing buildings with CLT requires development of novel panel attachment methods and mechanisms. Architects and engineers need to know the engineering strength properties of connected panels, especially in an earthquake prone area. This project will improve knowledge of three types of wall panel connections: wall-to-floor, wall-to-wall, and wall-to-foundation. Testing will determine the strength properties of metal connectors applied with diffferent types and sizes of screw fasteners. The data will be used to develop a modeling tool that engineers can use when designing multi-story buildings to be constructed with CLT panels.