Timber rivet connections, originally developed for use with glulam construction, may be a viable option for use with structural composite lumber (SCL) products. Tests were conducted on small samples to assess the performance and predictability of timber rivet connections in parallel strand lumber (PSL) and laminated strand lumber (LSL). The test joint configurations were designed to exhibit ìrivet failuresîósome combination of rivet yield and bearing deformation in the compositeóas opposed to wood failure modes, such as block-shear tear-out or splitting.
Results suggest that per-rivet design values should fall between 1 and 2 kN, depending on species and density of the composite and load direction with respect to grain of the composite strands. Timber rivets performed better in LSL than in PSL and better in yellow poplar PSL than in Douglas-fir or Southern Pine PSL; 40-mm rivets in yellow poplar LSL gave roughly equivalent performance to 65-mm rivets in yellow poplar PSL.
Project contacts are John B. Peavey at Home Innovation Research Labs and Xiping Wang at the Forest Products Laboratory
The proposed study will evaluate the moisture performance of balconies and decks in midrise multifamily and mixed-use wood-frame buildings with various types of exterior cladding materials. The study will culminate in recommended best practices for balcony and deck construction in midrise wood-frame buildings, with the focus on water management and integration with the primary building enclosure systems. A broad range of finishes and balcony configurations will be evaluated for applications across various construction markets and climatic conditions. The outcome will include a set of specific details and solutions for durable wood-frame deck and balconies with focus on the interface with the exterior wall systems.
Project contact is Shiling Pei at the Colorado School of Mines
NHERI Tallwood project is an effort to develop and validate a resilient-based seismic design methodology for tall wood buildings. The project started in September 2016 and will last till 2020. The project team will validate the design methodology through shake table testing of a 10-story full-scaled wood building specimen at NHERI@UCSD. It will be the world's largest wood building tested at full-scale.
Use of structural composite lumber products is increasing. In applications requiring a fire resistance rating, calculation procedures are used to obtain the fire resistance rating of exposed structural wood products. A critical factor in the calculation procedures is char rate for ASTM E 119 fire exposure. In this study, we tested 14 structural composite lumber products to determine char rate when subjected to the fire exposure of the standard fire resistance test. Char rate tests on 10 of the composite lumber products were also conducted in an intermediate-scale horizontal furnace. The National Design Specification/Technical Report 10 design procedure for calculating fire resistance ratings of exposed wood members can be used to predict failure times for members loaded in tension. Thirteen tests were conducted in which composite lumber products were loaded in tension as they were subjected to the standard fire exposure of ASTM E 119. Charring rates, observed failure times in tension tests, and deviations from predicted failure times of the structural composite lumber products were within expected range of results for sawn lumber and glued laminated timbers.
The primary outcome of this work is to provide integrated analysis of the environmental, financial, and social benefits and costs of using CLT in tall wood buildings. Secondary outcomes will be (1) information, including a design team checkoff that can be used to inform the building community as they make decisions on specific, new building projects, and (2) an informational foundation for these stakeholders and others to begin to evaluate the complex tradeoffs between, and optimization of, environmental, financial, and social benefits and costs.
The development and use of tornado shelters have helped reduce loss of human life associated with extreme weather events. Currently, the majority of shelters are built from either steel or concrete. The development of the crosslaminated timber (CLT) industry in the United States has provided an ideal wood product to resist the debris impact...
Over the past several decades, the market for ready-to-assemble (RTA) products has grown significantly. RTA kitchen cabinets and furniture are commonplace because they can be shipped flat and assembled on site, which has greatly reduced shipping costs associated with an otherwise voluminous product. Packaged with necessary hardware and instructions, these RTA products are typically easy to assemble and fool proof. The development of a standardized safe room using CLT that is ready to assemble, easy to ship, and quick to fabricate on site would not only increase the level of safety for our population but also increase the market opportunity for these engineered wood products. This research is an extension of research by the USDA Forest Service, Forest Products Laboratory, to develop a do-it-yourself safe room constructed from wood that can be incorporated into existing housing and that utilizes commodity wood products.
The objective of this project is to develop a RTA tornado safe room and shelter from CLT for use in existing and new residential and commercial construction.
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 the sun after being wetted by rain. The same phenomenon is likely to occur in CLT walls with these types of claddings (Fig. 1). General guidance on CLT building envelope design was published in chapter 10 of the U.S. CLT Handbook, which cautions that inward diffusion of moisture from absorptive claddings could lead to moisture accumulation in CLT based on initial computer modeling predictions. Experimental measurements are needed to provide a stronger basis for design of CLT exterior walls.
The objectives of the project are to measure moisture conditions in CLT walls with absorptive claddings under exposure to simulated rain and sun and to identify design and construction practices that minimize the risk of moisture accumulation in different U.S. climates.
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.