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.
This addendum completes the presentation of the data and research findings for the project entitled "Development of a high performance OSB panel." Most of the short-term test results and preliminary long-term creep data were summarized in a previous report (Project No. 38-43-M-410) which was submitted to the Canadian Forest Service. This addendum to that report includes new data on rolling shear, revised data on shear-through-thickness, and creep data collected during a load duration of nine months, followed by a three-week creep recovery. In addition, the effects of parameters such as strand length and climatic conditions on the engineering properties are discussed for OSB, waferboard, and plywood panels. Utilization of long strands improved the majority of the properties of OSB panels produced with commercial strands. This improvement, however, was not observed for the OSB panels produced with laboratory strands.
In response to a need for technical information to support the design of wood trusses in Canada, the Truss Research Program was established. Forintek's role in the Truss Research Program consisted of two projects: Truss Testing and Analysis, and Strength Variations in Trusses. The first project funded by the wood truss industry, focussed on establishing the structural reliability of residential pitched chord trusses and developing experimental data to verify truss analysis tools used by the truss industry. The second project, funded by the CFS, which is the topic of this report, provided the lumber properties information for the program. The combined loading equipment developed under this project has been used to test 2x4 S-P-F 1650f-1.5E MSR lumber under axial compression and bending loads. This data will now be used to verify a comprehensive stochastic finite element model that is currently under development at the University of British Columbia. A lumber design procedure comprised of a new interaction equation and factors to quantify load configuration effects for truss applications was developed under this project and at U.B.C. The design procedure was accepted in principle by the Technical committee on CSA-O86.
This report describes how the truss research project facilitates wood design code changes. In addition to addressing the code discrepancies, this effort provided an opportunity for the lumber producers, through Forintek and the Canadian Wood Council, to gain a better understanding of the needs of the truss industry. It also provided an opportunity for the truss industry to gain a better understanding of the structural performance of lumber and the potential benefits of participating in the development of design codes and standards.
The bearing strength of Hem-Fir MSR lumber has increased from 11 to 38% over the previous bearing strength values. The upgraded design values will be published in the upcoming supplement to the Canadian Engineered Wood Design code, CSA-O96.1-M94. This code change was assisted in part by data developed in this project on the bearing strength of Hem-Fir. This code change, although it did not affect the bearing strength of visually grade Hem-Fir lumber, is significant to the utilisation of Hem-Fir MSR lumber in the Canadian market. Grades of MSR Hem-Fir lumber 1650f-1.5E or higher now have the same bearing strength values as S-P-F MSR lumber. This simplifies the design code when MSR lumber is specified and allows the full potential of MSR Hem-Fir lumber to be used in engineered wood applications such as trusses. Additional data are being collected on the performance of Hem-Fir lumber under constant loads. This data will create a data base on Hem-Fir lumber similar to that developed for S-P-F and D.Fir-L in 1993-1994.