Assessment of the post-fire residual bearing capacity of FRC and hybrid RC-FRC tunnel sections considering thermal spalling

A design-oriented numerical model for the analysis of RC, FRC, and RC-FRC tunnel sections exposed to fire with different spalling parameters is presented. The conceived in two steps: first determination temperature field cross-section according parameters; second bearing capacity based on thermal section. At last, a parametric study was conducted evaluate effect curve, parameters, reinforcement type, rebar’s concrete cover sections. results showed that use FRC as total or partial substitution RC mitigates fire-related reduction Moreover, increasing beneficial only if avoided. When occurs, solutions yielded lowest reductions among tested.