ABSTRACT

The charring depth, rate and residual cross-section have a significant influence on the mechanical resistance of timber members in fire. In case of various dimensions of fissures, it is possible that as the cross-section reduces to the residual one, the mechanical resistance will be reduced as well. In the absence of rules that allows incorporating the influence of fissures on the charring rate, this paper is focused on the numerical analysis and experimental measurements of selected dimensions and number of fissures. In terms of results, the smaller fissures can be neglected, whilst the bigger fissures should be taken into account by means of increased value of the charring rate, or by advanced calculations.