Project contacts are Frederico França at Mississippi State University and Robert J. Ross at the Forest Products Laboratory
With the rapid development of CLT manufacturing capacity around the world and the increasing architectural acceptance and adoption, there is a current and pressing need regarding adhesive bond quality assurance in manufacturing. As with other engineered glued composites, adhesive bondline performance is critically important. Bondline assessment requires technology in the form of sensors, ultrasonics, load cells, or other means of reliable machine evaluation.
The objectives of this cooperative study are to develop quality assurance procedures for monitoring the quality of mass timber and CLT during and after manufacturing and to develop assessment techniques for CLT panels in-service.
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.
Initially, timber was considered only as an easily accessible and processable material in nature; however, its excellent properties have since become better understood. During the discovery of new building materials and thanks to new technological development processes, industrial processing technologies and gradually drastically decreasing forest areas, wood has become an increasingly neglected material. Load-bearing structures are made mostly of reinforced concrete or steel elements. However, ecological changes, the obvious problems associated with environmental pollution and climate change, are drawing increasing attention to the importance of environmental awareness. These factors are attracting increased attention to wood as a building material. The increased demand for timber as a building material offers the possibility of improving its mechanical and physical properties, and so new wood-based composite materials or new joints of timber structures are being developed to ensure a better load capacity and stiffness of the structure. Therefore, this article deals with the improvement of the frame connection of the timber frame column and a diaphragm beam using mechanical fasteners. In common practice, bolts or a combination of bolts and pins are used for this type of connection. The subject of the research and its motivation was to replace these commonly used fasteners with more modern ones to shorten and simplify the assembly time and to improve the load capacity and rigidity of this type of frame connection.
Although not yet seen as common practice, building with cross laminated timber (CLT) is gaining momentum in North America. Behind the scenes of the widely publicized project initiatives such as the Wood Innovation Design Centre Building in Canada and the recent U.S. Tall Wood Building Competition, substantial research, engineering, and development has been completed or is underway to enable the adoption of this innovative building system. This paper presents a brief overview of the current status of CLT building development in North America, highlighting some recent U.S. and Canadian research efforts related to CLT system performance, and identifies future CLT research directions based on the needs of the North American market. The majority of the research summarized herein is from a recent CLT research workshop in Madison, Wisconsin, USA, organized by the USDA Forest Products Laboratory. The opportunity and need for coordination in CLT research and development among the global timber engineering community are also highlighted in the conclusions of this paper.
Project contact is Hongmei Gu at the Forest Products Laboratory
The FPL team is in charge of developing a full comparative LCA study for three multiple-story mass timber buildings and their concrete alternatives in the U.S. Northeast region, with Boston as the point location. Using these three comparative LCAs, this research will determine the GHG emissions reduction potential from mass timber use in the building sector for the U.S. region. This may increase potential for growth in wood utilization, timber harvest, and forest management practices through the market demands.
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.