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.
Tension proof loading has been shown to be effective in eliminating low-strength fingerjoints, and a proof load stress level of 1.3 times the allowable stress value was found to be optimum. This confirms the tension proof loading stress requirement of the Canadian National Lumber Grades Authority (NLGA) for fingerjoined lumber.
Proof loading stress levels were chosen at 1.0, 1.3 and 1.6 times the allowable stress, and loading rates were selected so that target stress was attained in 0.2, 6.0 or 60 seconds. The only effect of loading rate was a small increase in strength values for weaker specimens when tested at faster loading rates, along with increased variability; therefore, it is strongly recommended that very fast loading rates be avoided, and a loading rate be chosen so the desired stress level is attained in about one second.
FPInnovations – Forintek performed this two-year study to provide a sound basis for evaluation of the tension proof-loading of fingerjoined lumber. The findings will be useful to the fingerjoined-lumber industry in refining the process and promoting its benefits to end users and regulators.
The objective of the project is to develop/improve practical, reliable and internationally recognized methods for assessing/pre-screening the long-term structural performance of engineered wood products used in residential and non-residential applications.
This report presents a survey of the performance of wood-frame construction in a number of recent earthquakes. After a review of the dominant factors that affect the seismic behaviour of buildings, the following earthquakes are examined: Alaska, 1964; San Fernando, California 1971; Edgecumbe, New Zealand 1987; Saguenay, Quebec 1988; Loma Prieta, California 1989; Northridge, California 1994; and Kobe, Japan 1995. Wherever possible, the behaviour of buildings is related to the measured peak horizontal ground accelerations.