Tests were carried out to determine the resistance of lumber bolted to concrete and subjected to ramp loading in the longitudinal direction of the wood. Specimens were made from Hem-Fir and from SPF lumber. Anchor bolt sizes studied were nominal 1/2 in. and 3/4 in. in diameter. Both lumber and anchor bolts were representative of material usually used in the construction of low-rise timber structures. It was found that the minimum strength of a connection with a single bolt exceeds the characteristic strength used by current design procedures in CSA O86.1 by a factor of 1.6 for 1/2 in. diameter bolts and a factor of 2.0 for 3/4 in. diameter bolts. Reasons for this underestimate of the strength of bolted wood-to-concrete connections are attributed to (a) a low estimate of the calculated embedment strength of bolts in wood, (b) a low estimate of the embedment strength of bolts in concrete, (c) bolt yield strength 14 to 37 percent higher than that specified in CSA O86.1, and (d) lack of a model for the strength of bolted connections which accounts for the anchorage of wood provided by washers, and friction between the concrete and the wood member. Some changes in the current design method which would improve the ability of this procedure to predict the strength of bolted wood-to-concrete connections are recommended.
Wood failure evaluation is the key criterion for predicting the long-term durability of plywood. At present, the conventional visual method for plywood wood failure evaluation is slow and subjective. Even experienced evaluators can show significant differences in their evaluations on the same plywood specimen and an individual evaluator can make different wood failure estimates on the same specimen at different times. Differences among evaluators can be as high as 50% for some samples. Evaluations can be influenced by room lighting, the wood species, sample treatment, and readings from prior samples. An automatic wood failure evaluation system using image analysis techniques could potentially be programmed to consider all the variables and respond with consistent wood failure values regardless of the experience level of the machine operator. This report describes the results of a one-year project in which a system for automatic plywood wood failure determination was investigated. A color optical imaging system was assembled and the preliminary work of compiling suitable algorithms was completed with promising results. The imaging system was 100% effective in reproducing individual sample values. Samples were sorted according to plywood type and test method to develop appropriate program algorithms for each category. The wood failure program was then further developed to automatically detect wood species and test method, thus avoiding the need for specimen separation prior to evaluation. Based on nearly 1200 samples in four categories, the differences in average values of wood failure between human evaluation and machine vision were found to be less than plus or minus 5%. In addition, a minimum of 85% of individual machine readings fell in the plus or minus 15% range of deviation expected of human wood failure readers. The imaging system was more accurate for light-colored specimens (i.e., Canadian Softwood Plywood) than darker-colored specimens (i.e., Douglas fir ) and for specimens where resin had been applied by spray. In order to make the imaging system more reliable and robust, the algorithm parameters now need to be fine-tuned based on a larger sample database.
Although the code provisions for dealing with the long-term structural performance of wood products are based solely on tests on solid sawn lumber, these provisions are currently applied to composite or engineered wood products. There are concerns among code writers that some composite wood products may not necessarily exhibit the same long-term behaviour as lumber. In order to address these concerns, a standard test needs to be developed for assessing the long-term performance of such products. Although test protocols are available from previous studies, the extensive testing originally conducted for lumber was judged impractical for composite wood products. This is because of the proprietary nature of composite wood products and the desire to allow manufacturers, whenever possible, the ability to alter a product to suit the available fibre resource and market demands. These conditions are particularly true during initial product development where rapid and cost effective assessment procedures are needed. An American Society for Testing and Material (ASTM) subcommittee was therefore established to prepare an appropriate consensus standard. This project is designed to allow Forintek staff to participate in that process as well as develop the baseline performance data for lumber, which the composite product performance will be compared to, in the proposed ASTM standard. The members of the two Task Groups of the ASTM Section D07.01.04, prepared a draft of the "Standard Specification for Evaluation of Load Duration and Creep Effects for Wood Products". This draft included a simple verification method, and more extensive probabilistic method. The verification method requires the producer to demonstrate that his product has equal or better long-term performance than lumber, while the probabilistic approach requires producers to develop extensive test data and then perform analysis to quantify the DOL and creep factors. The verification test portion of the draft standard has been applied to a sample of lumber to obtain the baseline performance data at low load levels. Results showed that this group fulfilled the requirements stipulated in the verification method in the draft ASTM standard. The ASTM draft standard has been balloted at the section level. Due to the negative votes received on the draft standard, the ballot was withdrawn. A new draft is planned to be balloted in the 1997/98 fiscal year. In the meanwhile, some representatives of the structural composite lumber industry have proposed to incorporate the verification portion of the draft standard into the ASTM Standard for Structural Composite Lumber. They prepared a paper including this approach, and compared the DOL performance of some composite lumber products against the lumber results provided to them by Forintek and the USFPL. They found that the verification method can be used to check the equivalency of the long-term structural performance of two composite lumber products. The Canadian Standards Association Technical Committee on Engineering Design in Wood has accepted the methodology given in this paper.
Commercial thinning at a relatively young age will result in changes not only to log size but to wood quality as well. One important change in the thinnings will be the increased proportion of juvenile wood relative to mature wood. In western hemlock (Tsuga heterophylla (Raf.) Sarg.), where the difference in wood density between juvenile wood and mature wood is relatively large, a higher proportion of juvenile wood can result in reduced lumber strength and lower pulp yields. Another change will be seen after thinning in the remaining standing trees; late-release growth pattern changes in terms of grain. The present report summarizes the results of X-ray densitometric analysis of 50-year-old western hemlock trees thinned from 1656 and 956 stems/ha plots, and amabilis fir (Abies amabilis (Dougl.) Forbes) from the 956 stems/ha plot. Results were compared to old-growth reference data, and to a recently completed basic wood properties study of 90-year-old western hemlock (Jozsa et. al., 1997).
Across North America the amount of tensioning used in bandsaws varies drastically. Sawblades tensioned to fit circle gauges from 28 feet to 80 feet in diameter are in regular use and performing very well. This raises the questions as to what is the right amount of tension and what effect does it have on cutting accuracy. In this study, the cutting accuracy of five sawblades, with varying levels of tension, have been measured and compared. The results show that little change occurs in cutting accuracy once enough tension has been put into the blade for it to fit an 80-ft circle gauge.
This study compares the machining properties of 15 individual species within B.C.'s SPF and hem-fir groups demonstrating the benefits of sorting by individual species. In addition, the machining properties of B.C.'s under-utilized species (e.g., trembling aspen, black cottonwood) are compared to those of well-established softwood species (e.g., Douglas-fir, western hemlock). Finally, the study determined the average force necessary to withdraw two types of fasteners (nail and screw) from each of the wood species.
To develop new projects in the field of sawmill optimization, 21 sawmills were surveyed in British Columbia and Alberta. The project ideas were intended to help the sawmill industry to improve lumber recovery. This report describes the survey methods used, the type of sawmills included in the study, the specific research projects proposed, and the method by which priorities were assigned to projects.
Experiments were conducted to evaluate steam-injection pressing of plywood and LVL using saturated and superheated steam conditions. Three steam-injection times of one, two and three minutes were used to prepare 7-ply plywood and steam-injection times of three, five, seven, and nine minutes were used to prepare LVL. The results showed optimum pressing times were achieved with the steam-injection times of one and two minutes for the 7-ply plywood and seven minutes was found to be an optimum steam-injection time for LVL. All the panels prepared under a variety of steam conditions exhibited excellent bond quality and the average % wood failure was greater than 80% in all cases. For the preparation of the 7-ply plywood and LVL, using the optimum steam-injection times for both superheated and saturated steam conditions, the pressing time was reduced by over 30% compared to conventional platen heating. An economic analysis of return on investment for thick plywood products and LVL shows the pay-back period for retrofitting an existing plywood or LVL press for steam injection is less than three months.
A concept for a wood frame construction system suitable for medium-rise buildings and/or buildings with large openings has been developed and patented. The system is composed of prefabricated column modules and continuous beams that can be cut to size at a manufacturing plant. Column modules, a primary feature of the system, have four standardized configurations depending on the configuration of the beams they are supporting. Each column module has at least two full-module-height vertical members spaced apart and diagonally-braced with wood and steel to provide lateral resistance to wind and earthquake forces. The column modules are placed at optimum plan spacings to support large-span continuous beams prefabricated with engineered composite products. A goal of this research was to prove the principle that the modular column assembly as originally patented can carry loads of a magnitude that could be expected in service. It was apparent from load-testing the patented design, however, that many shortcomings exist. In some cases this design could not meet test case load values expected in service, and could not sustain high design load levels for very long without softening. The patented design, in spite of reasonable ductility and good elastic recovery, also lacked the stiffness necessary to resist light horizontal loadings such as daily winds. As a result of many difficulties identified with this patented prototype, a second-generation column module design (with preliminary modeling analysis in hand) is awaiting consideration for construction and testing. The key to the success of this building system lies with the correct design of the column module to render appropriate horizontal racking and vertical load-carrying performance. It is recommended that the results of this research be pursued further to address some of the shortcomings found during the testing of this first patented prototype specimen. This proposed work should include finalizing examination of the racking test data of the original column module design, finalizing the modeling of a second generation prototype that addresses the shortcomings of the original design, and constructing and testing a second-generation prototype design. The aim is to deliver a viable system (with supporting data) to any potential collaborator for commercial considerations. This work should be complete and a final report submitted by 31, August 1997.
A prediction model for long term creep and creep-rupture behavior of OSB was developed by the late Senior Research Scientist, Dr. L. Palka at Forintek Canada Corporation, Vancouver, BC, Canada. By using one minute destructive ramp load test results, the "Palka Model" allows the prediction of time-to-failure and time-dependent creep deformations under given sustained loads. Verification testing of the model was performed on time-to-failure at the 75% sustained load level and on creep deformation behavior at the 25% and 50% levels. The verification tests gave encouraging results which showed a reasonable agreement between the test results and the Palka Model predictions. The Palka Model is recommended for use as a first approximation prediction tool for long term creep behavior of OSB. The model prediction technique appears ideal to assist in product development decisions and also in evaluation of load duration and creep factors in timber design codes.
Canada is a resource rich country which relies heavily on its exports, with forest products being the single largest contributor to the trade surplus. For this reason, the study of trade-flows and market access issues is considered paramount to the forest industry's, and in turn, Canada's prosperity. The initial objectives of this project were: 1. To acquire wood product flow and market access information for Canadian product consumption in North America and Japan, with an emphasis on regulations (codes and standards); 2. To develop a particular market opportunity in one major non-residential structural wood product application in North America and/or Japan by initiating key codes and standards activities. Related to the first objective, it is recognized that virtually no solid wood product trade analysis has been reported in the literature beyond very broad aggregates, such as "softwood lumber". Given the diverse nature of wood product supply and demand (including species and grade of lumber), this greatly obscures the information used by government, forest product researchers and industry. The development of a data matrix and forecasting model with sufficient product detail will greatly aid in the identification of areas of competitive advantage that Canadian products possess (or potentially possess). As a result, two activities have been undertaken in the first year of this project. The first was to determine the extent of existing trade modelling efforts in North America and/or Japan, to avoid duplication and foster synergies. It was discovered that the Canadian Forest Service's Industry, Economics and Program Branch has been, and continues to develop, a model of the N.A. solid wood sector in conjunction with the USDA Forest Products Laboratory in Madison. It was decided that the strongest support to these efforts could be obtained by focusing efforts on the extension of the product detail, and to conceptualize methods in which such detail could be incorporated into existing efforts. This constituted the second effort; a cross-section of the quantitative and qualitative information discovered is reported here. To address the second objective, the market for finger-jointed and MSR lumber use in wood trusses were investigated, including the identification of codes and standards barriers. However, the identification of the wood truss market has lead to tremendous technical product-related issues which must be dealt with before market access issues can be properly identified. This has lead to a separate proposed effort in conjunction with the Western Wood Truss Association of British Columbia. Due to the problems associated with the second project objective, and industry concerns heard at the Forintek Technical Advisory Committee Meetings over the broad scope of the first objective, this project is being terminated in favour of new project proposal. The concerns of industry were at least partially supported by the results of this project; it was determined that the level of wood product detail available is insufficient to adequately deal with market access issues. While the importance of identifying trade-flow trends has not diminished, the need to identify specific attributes of wood products in end-use applications has become clear, both in the identification of competitive threats from other wood products and non-wood substitutions. Thus, the new proposal is a natural extension of North America and Japan Market Access.
In Western Canada, major problems in drying sub-alpine fir (Abies lasiocarpa (Hook)), either alone or as part of the spruce-pine-fir species mix, have been largely attributed to the occurrence of wet-pocket wood in this species. The species is notorious for containing wet pockets that significantly extend the drying time and make it difficult to create a uniformly dried end product. Some of the problems are usually caused by the initial high and variable moisture contents, which causes the lumber charge to have wide variations in final moisture contents after drying. Since there has been an increase in harvesting of sub-alpine fir in recent years, the industry is faced with drying larger amounts of this species. Therefore, there is a need to develop suitable schedules for sub-alpine fir. The objective of this study was to develop or improve current drying schedules for sub-alpine fir containing wet-pockets based on wood properties and drying behaviour by manipulating drying conditions. Twenty-three kiln drying runs, using Forintek's experimental 3-foot kiln, were performed using different combinations of air-drying, pre-steaming and conditioning in the drying schedules. Air-drying phase of the schedule was 0-, 4- or 8-weeks; pre-steaming phase was 0-, 4- or 8-hours; and, conditioning phase was 0-, 2- or 4-hours. Basic density, initial and final moisture content distributions, were determined for each lumber load as well as an estimation of the amount of wet-pockets were recorded. Moisture diffusion was examined for wet-pocket wood with different pre-steaming periods. Use of hand-held moisture meters to determine the final moisture content of the wood was examined. In general, air-drying can significantly reduce lumber kiln drying time. The air-drying period for this study was during the summer months. The effect of 4-weeks air-drying and 8-weeks air-drying are similar. Air-drying can improve final moisture content distribution within each run. There is a reduction of over-dried and under-dried percentage with air-dried lumber when followed by kiln drying. Pre-steaming slightly increased the drying rate when average MC of the load was below about 40%. Pre-steaming has no significant effect on final moisture content distribution with in each run. The diffusion of moisture in the wet-pocket wood appeared to increase when the wood was pre-steamed. Based on the results in this study, the best strategy for drying sub-alpine fir is using air-drying in combination with the mill's conventional schedule. This report provides details of the different combinations which mill personnel can use to develop their own drying strategy to improve the quality and uniformity of sub-alpine fir lumber.
Forest products companies in the ILMA region covering four areas, Cranbrook, Kootenay, Vavenby and Okanagan, were surveyed for their current mill residue utilization. Although the Cranbrook area showed the lowest utilization of bark residues (0 %), it showed the highest utilization for whitewood, sawdust and shavings (98%). Overall, the Okanagan area generated the largest amount of bark and whitewood residues and showed the highest utilization for these residues (69% utilization for bark and 86% for whitewood). The Kootenay area generated the second highest amount of bark and whitewood residues and showed the second highest utilization for these residues (67% utilization for bark and 76% utilization for whitewood). The amounts of bark, sawdust and shavings, slabs, trim ends and yard debris generated and utilized for the above four areas are presented in this report. In 1996, the utilization of bark and sawdust / shavings residues in the ILMA region as a whole was 49.8% and 83.8% respectively compared to 28% and 45% respectively in 1989 showing a substantial increase in utilization. The primary use for sawdust and shavings was found to be pulp furnish followed by particleboard/fibreboard furnish, internal process heat, and agricultural/bedding material. The primary use for the bark residues was for energy generation, either through cogeneration or for internal process heat. There are few value-added product opportunities for bark in comparison to sawdust and shavings. However, a new value-added hog fuel/bark board recently patented by Forintek may have potential to utilize some quantities of bark residues, providing a number of technical, environmental and economic questions can be satisfactorily addressed. Another new product, BiolimeTM, also shows some potential for utilizing large quantities of bark residues.
During May and June 1998, a series of forest fires in central Alberta had covered more than 370 000 ha of forest land. To minimize the volume losses associated with the fires, forest companies in the region and the Alberta Land and Forest Service were anxious to salvage as much burned timber possible. To provide information on the salvaging, sawmilling and pulping of burned wood, FERIC organized a workshop for companies and contractors affected by salvage operations. Nearly 200 people attended the workshop that was held in Whitecourt, Alberta on June 18th. The focus of the presentations was on the harvesting, sawmilling and pulping (including kraft, BCTMP and newsprint) of burned conifer and deciduous timber. However, other presentations included a brief review of the effect of fire damage on wood properties, composting wood residues and information on ring, rosser-head and flail debarkers. FERIC also presented information from studies it has undertaken on utilizing burned wood. These Proceedings summarize the presentations and the discussion during this workshop.
In the Winter of 1997, FERIC monitored a harvesting operation on northern Vancouver Island. The study was requested and funded by Forintek Canada Corp. and was to determine the costs of harvesting a coastal second-growth western hemlock stand. The operation was also used to test a computer model developed by FERIC, to evaluate the accuracy of prediction for volume distribution by sort and species and total value of timber harvested.
In response to requests from its members and partners, FERIC has investigated the problems and potential of using environmentally compatible hydraulic fluids in forest operations. This report summarizes the types of bio-oils currently available, their operational characteristics, their compatibility with forestry machinery, and important considerations for their use.
Commercial thinning is a topic that generates lively debate in any forestry-related gathering. Arguments for and against this treatment are many. As a result, many forest companies are uncertain of whether or not to proceed with commercial thinning operations. The Commercial Thinning Workshop was organized to provide a forum for discussion on many aspects related to thinning activities. The Workshop was sponsored by FERIC and Millar Western Industries Ltd., with funding assistance provided by Alberta Economic Development and Tourism
A pilot plant apparatus was built to electrostatically spray phenolic resin on strands. To evaluate the resin distribution on these strands, an image analysis method was developed. The experimental conditions in this study made it difficult to compare electrostatic treatments to control (non- electrostatic) treatments. Although not statistically significant, there were notable differences between these treatments which indicate that electrostatic resin application may improve panel properties and is therefore worth further investigation. First of all, the electrostatic treatment produced panels with a 10% higher internal bond than the control. Secondly, the resin distribution results show that the electrostatic spray, on average, covered a 30% greater area of the strands than the control even though both treatments applied resin at the 2% resin solids level. Further experiments using alternative test procedures are planned to compare electrostatic treatments to control treatments that simulate industrial conditions.