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.
The long-term experimental study of waferboard behaviour under selected ramp- and dead-loads, and in constant or changing environmental conditions were completed in 1992. These test results were only available in contract reports submitted to Forestry Canada, the Structural Boards Association and the U.S. Forest Products Laboratory. The Technical Committee of the Structural Board Association suggested last year, that, in addition to developing improved test methods, a wider distribution of the available long-term creep and creep-rupture information is needed, to promote marketing of structural panel products. To improve the accuracy of the test methods used in this exploratory study, a report entitled "Problems in measuring waferboard creep and their corrections" was prepared (Appendix I) by a co-op engineering student. To provide a Canadian input into developing European long-term test methods, Forintek staff participated in preparation of a state-of-the-art review of creep in timber construction, by summarizing "Basic knowledge" (Appendix II) in co-operation with the chairman of RILEM TC 112. To disseminate the results and implications of Canadian long-term waferboard experiments internationally, a paper entitled "An overview of bending creep and creep-rupture of waferboard panels: The Forintek experience" (Appendix III) was presented at the an international Duration of Load Workshop. Finally, to provide a basic comparison of long-term behaviour of plywood, oriented strandboard and waferboard panels under identical loads and environmental conditions, a draft entitled "Creep and creep- rupture of wood-base structural panels" (Appendix IV) was prepared jointly with U.S. Forest Products Laboratory co- operators. Each of these four papers attempted to answer a series of questions concerning improvements to long-term test methods, factors affecting long-term behaviour and their possible interaction, relationships between short-term and long-term properties, and the extent of similarities or differences between the long-term behaviour of wood and wood-based panel products. Future efforts should concentrate on developing internationally standardized test methods, and analytical techniques for predicting (at least some) long-term properties from short-term tests.
Long-term strength of Canadian commercial waferboard: 5/8-inch thick panels in bending - creep and creep-rupture data and interpretation - final project report
Lack of easy-to-use technical information about their long-term behavior could become a serious barrier to expanded use of waferboard panels. In cooperation with the Structural Board Association, the American Plywood Association and the U.S. Forest Products Laboratory in Madison, a long-term experimental plan was devised to provide missing information on the effect of different loading and selected environmental conditions on the static, creep and creep-rupture behavior of waferboard panels in Canada, plywood and oriented strandboard in the U.S., subjected to third-point bending. The broad data base collected, supplemented by other related information, provides a good basis for a detailed and unified evaluation of analytical models to predict creep and creep-rupture behavior. The same data base would also allow estimation of the code factors needed for reliable design of individual waferboard panels subjected to flat-wise bending.
