Higher bearing strength values for Hem-Fir, where justified, will allow designers to realise the full strength potential of the lumber. Machine stress rated (MSR) lumber would benefit the most from an increase in the Hem-Fir bearing strength. Although there are few Hem-Fir MSR lumber producers, it is anticipated that given the recent or planned increase in installed kiln capacity on the west coast, more mills will be considering producing MSR lumber. Acceptance of Hem-Fir MSR lumber in the marketplace will depend on the design values assigned to Hem-Fir MSR lumber. The objective of this project is to establish characteristic bearing strength values for the Hem-Fir species group in CSA O86.1 and progress to date is described.
This report summarizes the progress from Year 3 of the multi-year Lumber Properties project. All activities continue to conform to the guiding principles adopted by the Lumber Properties Steering Committee (LPSC) at the start of the program. This year the first steps were taken in preparing information for discussion with the new American Lumber Standard Committee (ALSC) Lumber Properties Task Group (TG). Work continues on the review of the Norway spruce testing program and the development of an on-going monitoring program.
The program has enabled the wider industry group represented by the LPSC, to be involved in monitoring progress on the program and providing strategic direction. The support has also enabled the program to retain the necessary statistical support from the University of British Columbia to not only address Canadian lumber property issues, but also contribute to technical discussions at the ALS Lumber Properties TG.
This report summarizes the progress from Year 4 of the multi-year Lumber Properties project. All activities continue to conform to the guiding principles adopted by the Lumber Properties Steering Committee (LPSC) at the start of the program. This year support was provided to statisticians from the University of British Columbia’s Department of Statistics to meet and work with researchers and statisticians from the US Forest Products Laboratory (USFPL) in Madison, WI. All physical testing under the ongoing monitoring pilot study was also completed, allowing the UBC statisticians to continue work refining their global lumber properties simulator. Work is continuing on the collection of secondary properties for Norway spruce and on the analysis of the data collected to-date.
No activities requiring significant resources were carried out under the Resource Assessment and the Special Products Initiative. Instead, these resources were redirected to cover shortfalls in the provincial funding under the Strategic Framework Initiative, so that the statistical work with the USFPL could continue.
The current Canadian Lumber Properties program was established to support multi-year research on topics judged by the industry to be critical to the safe and viable use of Canadian dimension lumber in structural applications. This program, in combination with the National Lumber Grades Authority’s grading rules and the accredited third party grading agencies form the backbone of the Canadian lumber quality system. This system enables Canadian lumber producers to grade and ship Canadian lumber for use in North American and overseas structural building applications.
When initiated in 2005, the program focussed on five areas. The effort is now focussed on three areas: 1) maintenance of existing lumber design values by means of an ongoing lumber properties monitoring program; 2) working with the US/Canada task group established to guide the development of standard procedures published in ASTM D1990 and used in the establishment of lumber design values; and 3) liaise with university-based research groups to leverage research suitable for addressing longer-term research needs in the area of lumber properties.
One of the planned activities for 2009-10 was the start-up of a trial on-going lumber properties monitoring program. The program, which is a longitudinal survey of lumber produced from mills across Canada, would have been modelled after the Pilot Ongoing Monitoring program that began in 2006 and ended in 2008. Because of the severe downturn in the industry starting in 2008, the proposed 2009-10 program needed to be postponed to accommodate the shortfall in industry funding. There were also concerns with the significant changes in production levels both within and between regions, and the potential disruptions to sampling because of unanticipated mill closures. Available resources were instead directed at establishing how best to respond to practical issues observed during the downturn, such as the closure of a mill that would have or had been providing samples. Following discussions during the year and consideration of possible alternatives, it is recommended that the sampling plan as used in the Pilot program be restarted. Additional details on the augmented mill list to account for mill closures are provided in the recommendations section of this report.
In the other major area of study, University of BC (UBC) and US Forest Products Laboratory (USFPL) statisticians met to discuss and evaluate alternatives to the ASTM D1990 procedures for developing design values for groups of wood species. Although the proposed alternative procedures would address one or more of the statistical anomalies identified in the ASTM D1990 procedure, the American Lumber Standard Committee (ALSC) Lumber Properties Task Group (LPTG) charged with reviewing the potential changes did not see any practical improvements to warrant changes to the procedures but suggested that the effort focus on establishing criteria for species grouping. Because of the potential inter-relationship between the species grouping procedures and other procedures used to assess in-grade lumber properties, it is recommended that efforts be maintained in this area and adjusted as required to respond to the needs of the LPTG.
Lastly, in late 2009, the UBC Dept. of Statistics and the Simon Fraser University Dept. of Statistics and Actuarial Science were awarded a research grant by the Natural Sciences and Engineering Research Council (NSERC) of Canada to establish the “Forest Products Stochastic Modeling Group”. FPInnovations is the industrial collaborator on this initiative. Several student projects targeting longer-term lumber properties research needs have been initiated, and a sample of suggested projects is included in the appendix of this report.
With the appropriate mainline attachment, chain chokers are a viable alternative to conventional wire rope chokers, particularly for small-scale operations. This report provides users of tractor-mounted winches and cable skidders with technical information on chain chokers. The report covers type of steels, chain specifications and grades, and how to inspect chains for wear elongation. The various components (e.g. sliding hooks, rings) used to assemble chain chokers are also discussed.
Changes to the Canadian timber engineering codes over the last 10 years have made it necessary for the wood truss industry to update the wood truss design procedures. The Truss Research Project was established to assist the truss industry to resolve some of the issues arising from the code changes. While most of the issues deal with the analysis of metal plate connected trusses and are therefore specific to the truss industry, some issues that deal with the fundamental strength properties of lumber apply to other engineered timber construction. One area that requires research is the strength of lumber under combined bending and axial loading conditions. A program to model the within-member strength variations of lumber is underway at the University of British Columbia. The purpose of this Forintek project is to develop equipment that can test lumber under combined bending and axial loads. This equipment will be used to validate the lumber strength model. The equipment to test lumber under bending and axial loading has been developed. This report presents a discussion of the equipment specifications and some of the limitations of the equipment identified to-date. The combined loading tester for lumber is currently undergoing verification and trial testing. It will be ready for use in the 1995/96 fiscal year.
In early 1997, FERIC performed an operational evaluation of five onboard weigh scales for semi-trailers. The purpose of the study was to assess the scales in the field under normal operating conditions and as used by the drivers. The scales were based on load cells, pneumatic devices, or combinations thereof, and were intended for uses with either leaf-spring or air suspensions. Data were collected on the ease of use of the scales, their accuracies, and their short-term reliability, and were used to assess the suitability of the scales for in-woods use. The study found that four of the scales were consistently with the tolerance (1500 kg) accepted by the Ministère des Transports du Québec, which served as a reference.
Tests on floors at two houses of the Mark XI project under concentrated load were conducted in order to determine if changes in performance could be detected. The performance was compared to the response obtained at previous test of the sam floors by Onysko et al.(1981a) and to the response obtained by Onysko et al.(1981b) on floors that were dried in the laboratory. The increases in maximum deflections for the four floors studied are explained in terms of moisture content changes and differences between floors in material properties, joist spacing, span and loads. The effects of cross-bridging and strapping are discussed. Measures of the degree of load sharing and composite action are defined. It is concluded that a reduction of performance may be due primarily to an increase in moisture content in the subfloor with second order effects due to the reduction in effectiveness of cross-bridging and strapping.