Treesearch

Wood-plastic composites are becoming more important as a material that fulfills recycling needs. In this study, fire performance tests were conducted on several compositions of wood and plastic materials using the Ohio State University rate of heat release apparatus. Test results included five-minute average heat release rate in kW/m2 (HRR avg) and maximum heat release rate in kW/m2 (HRR max). As expected, the general trend was an increase in the values of HRR avg and HRR max with increasing concentrations of polypropylene or high density polyethylene.

The repair and remodeling of residential units in the existing housing stock is an important market for wood products. Included are many, and varied repair and remodeling activities and projects, some of which require substantial amounts of wood products, some of which do not. Currently, about 24 percent of all lumber, 23 percent of all structural panels, 15 percent of all nonstructural panels, and lesser amounts of engineered wood products consumed in the United States are used for residential repair and remodeling. This market has become much more important in recent years as the...

The worldwide movement toward performance-based building codes is prompting the need for new computational methods to predict fire endurance of wood assemblies. Progress in the past twenty years in understanding fire endurance of individual solid wood components has been achieved in many different countries. The greatest opportunity for major advance in fire research is the development of computational fire endurance models that incorporate heat transfer, thermal degrade, and structural analysis algorithms for not only single components but multiple-component assemblies subject to standardi...

The qualitative effect of air velocity on drying rate of lumber has long been known. This report provides quantification of the effects of air velocity on drying rate of individual eastern white pine boards. An empirical equation correlating moisture content with time during drying was used to aid in the analysis. The drying rate increased with air velocity for moisture contents above approximately 40% to 50%. The drying rate gradually decreased and tended to level off with air velocities above 3.05 to 3.56 m/s (600 to 700 ft/min) and moisture contents below approximately 80% to 90%. The...

This report presents information on trends in production, trade, consumption, and prices of forest product in the United States. Although national trends are dealt with for the most part, some information is given for regions, states, and Canada. The tables presented in this report are from information collected from industry trade associations and government agencies. Some of the tables show data that are derived from mathematical calculations and conversions from different units of measurement. These data are intended for use by anyone associated with wood-using industries. One major use...

Bolted connections often fail by a shear plug or by splitting beneath the bolt caused by tension perpendicular-to-grain stress as the bolt wedges its way through the wood. Preventing this type of failure enhances both the capacity and reliability of bolted connections. This research investigated the use of fiberglass reinforcement to enhance the load-carrying capacity of bolted wood connections. Matched specimens were reinforced with one, two, or three layers of bidirectional fiberglass cloth and configured to ensure a Mode I failure as defined by the yield theory in the National Design...

The objective of this paper is to illustrate how longitudinal stress wave techniques can be useful in tracking the future quality of a growing tree. Monitoring the quality of selected trees in a plantation forest could provide early input to decisions on the effectiveness of management practices, or future utilization options, for trees in a plantation. There will likely be utilization options that will include the production of structural products that use modulus of elasticity (MOE) as part of the grading criteria. Examples include machine stress rated (MSR), solid- sawn lumber and...

The conventional test method for determining the stacking life of corrugated containers at a fixed load level does not adequately predict a safe load when storage time is fixed. This study introduced multiple load levels and related the probability of time at failure to load. A statistical analysis of logarithm-of-time failure data varying with load level predicts the safe load that would yield a 5% probability of failure for any given storage time. Results were used to (a) quantify the performance of two corrugated fiberboards having significantly different components and (b) show the...

Medium-density hardboard is used extensively as siding on residential structures. One hardboard behavior that can be measured in the laboratory is thickness swell after exposure to water. This report reviews the literature on processing variables that are known to or likely to influence thickness swell. Where the literature on hardboard is sparse, research on other wood composition materials is cited, with appropriate caveats relevant to hardboard. Initially prepared as technical guidance to the U.S. Department of Housing and Urban Development, this report should be of interest to anyone...

Wood-inhabiting bacteria are associated with wood decay and may have an indirect influence on the decay process. Bacteria are able to affect wood permeability, attack wood structure, or work synergistically with other bacteria and soft-rot fungi to predispose wood to fungal attack. Bacteria that can inhabit chemically treated wood are recognized. The natural ability of certain bacterial genera to decompose creosote, mineralize pentachlorophenol, and tolerate chromated- copper-arsenate (CCA-)-treated wood is discussed with respect to their role in the biodegradation of chemically preserved...