Hygro-thermo-mechanical analysis of spalling in concrete walls at high temperatures as a moving boundary problem

摘要

A mathematical model allowing coupled hygro-thermo-mechanical analysis ofspalling in concrete walls at high temperatures by means of the moving boundaryproblem is presented. A simplified mechanical approach to account for effectsof thermal stresses and pore pressure build-up on spalling is incorporated intothe model. The numerical algorithm based on finite element discretization inspace and the semi-implicit method for discretization in time is presented. Thevalidity of the developed model is carefully examined by a comparison betweenexperimental tests performed by Kalifa et al. (2000) and Mindeguia (2009) onconcrete prismatic specimens under unidirectional heating of temperature of 600${\deg}$C and ISO 834 fire curve and the results obtained from the numericalmodel.