Experimental validation and simplified design of an energy-based time equivalent method applied to evaluate the fire resistance of the glulam exposed to parametric fire

An energy-based time equivalent method proposed by the authors was able to convert the fire resistance design of timber components under realistic fire exposure to a standard fire. In order to verify the effectiveness of the method, a series of parametric fire and standard fire experiments were carried out by testing representative two types of glulam, glued laminated timber (GLT) and cross laminated timber (CLT). Based on the comparison of the charring depth and the temperature distribution of the pyrolysis layer under the parametric and standard fires, it is fully confirmed that the method has good applicability to both types of glulam, which can effectively convert the parametric fire exposure into a standard fire. The test results also show that the fire performance such as temperature distribution of cross-sectional, charring depth and charring rate of the GLT and CLT with the same composition has a good consistency under the same fire. To further simplify the method, a prediction formula for surface temperature on the fire side of the timber was proposed through some approximate methods. The simplified energy-based time equivalence method can not only meet the accuracy requirements of fire safety design, but also provide more convenience for the designers.