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.
With the growing use of wood density as a design property, there is a need for a simple and rapid, but accurate, method of measuring wood density outside of a laboratory environment. In this report, a test apparatus developed at Forintek to accurately measure the relative density of small wood samples is presented. The apparatus was previously developed to measure the relative density of a large number of wood samples from an in-grade lumber testing program. Forintek's test set-up is an adaptation of the ASTM D2395 water immersion method. It consists of a micro-computer software and an electronic balance with a cage for submerging the test specimen. This apparatus may be used with waxed or unwaxed blocks. With this apparatus, test results from unwaxed (Forintek method) specimens may be calibrated to waxed (ASTM water immersion method)specimens provided the specimen size is maintained. In addition to the relative density, the oven-dry moisture content of the test specimen may also be determined using this apparatus. In this report, a comparison of the results from the Forintek method to the ASTM D2395 methods is presented. While not as accurate as the ASTM methods, ease of use, robustness, and level of accuracy make the Forintek method ideal for use in a mill environment, especially for ongoing quality control testing involving a small number of samples.