CHARRING RATE OF TIMBER IN NATURAL FIRES

摘要

A total of 32 glulam beams have been fire tested using three different fire curves and with different load levels.The aim of the project was to study the load bearing capacity and the charring rate under different fire curves and to gather data as to the variation of the response of timber beams in fire.Prior to the fire tests, the 32 beams were selected out of a total sample set of 45 glulam beams which was subject to reference testing and then grouping into 5 approximately equal groups in terms of mean and standard deviation of stiffness.One of these groups was subject to static bending tests until failure and was deemed to be representative of the strength of all of the other groups.During the fire tests the charring rate was determined from temperature measurements made at different depths and locations in the tested beams, as well as by inspection of the residual cross section after the fire test.This paper reports on the test programme as well as the measured charring rates during the fire tests.The results show that the fire intensity has a major influence on the charring rate as well the variance in charring rate over the course of the fire.The charring rate also varies with time during the fire exposure.Other measurements and analysis have been conducted although they are not the scope of this paper.