Reliability analysis of timber columns under fire load using numerical models with equivalent section temperature

This paper presents a modelling method for timber columns exposed to fire using the equivalent section temperature (EST), aiming to reduce the computational cost of the sequential thermal–structural analysis. The EST is to use a single temperature value across the section that can provide the same compression strength or bending stiffness as the original temperature field. The temperature–time curves, displacement curves, and fire resistances of the developed model and experimental tests are compared. The developed column models are further validated by a large test dataset. The reliability of timber columns under fire is evaluated based on the developed numerical model and trained surrogate model Polynomial Chaos Kriging (PCK). The random variables are considered for thermal and structural analysis and the failure probability of the column with increasing exposure time is calculated through different reliability assessment methods. • The equivalent section temperature (EST) method is developed for timber columns exposed to fire to simplify the numerical models for sequential analysis. • The timber column models using EST method are validated based on a large test dataset. • The performances of timber column models with and without EST are compared. • The reliability analysis is carried out using different assessment approaches based on the developed numerical models.