Abstract
A series of heating tests using a intermediate size furnace was carried out to comprehend charring behavior and temperature distribution in timber elements under various fire temperature conditions. In this study, glue-laminated timber panels of Japanese cedar or Douglas fir were used as specimens. The dimension of the specimens was 480 mm high, 480 mm wide and 100 mm thick. The height and width of the specimens were intermediate scale but the thickness was sufficient to reproduce full scale timber elements. Fire severities defined by fire temperature rise coefficient α and fire duration were main experimental parameters in this study. As the results of the heating tests, it became obvious that charring rates of timber elements under severe fire temperature by α = 690 were two times higher than that of standard fire exposure by α = 460. Charring rates under low fire temperature by α = 230 were about half of the nominal charring rate. A formula derived from heat conduction equation of semi-infinite solid was adequate to calculate temperature distribution in un-charred timber wood.
