Thermo‐hygro‐mechanical analysis of concrete

The computational analysis of thermohygrometric and mechanical behaviour of concrete structures is carried out by means of the finite element method. To evaluate the thermal and hygral performance of this material together with the damage and creep effects, the knowledge of the heat and moisture transfer processes taking place inside the medium is first required and then the consequent mechanical behaviour can be analysed. The theoretical approach used to obtain the governing differential equations for heat and moisture tansfer is based on the procedure of averaging continuum equations applied to heat and mass transfer and drying processes. According to that model the same set of equations is used to represent both the saturated zone (if present), the unsaturated one and the water‐vapour phase changes. The mechanical formulation is based on the virtual work principle and incorporates Prony–Dirichlet series expansion to represent the relaxation or creep functions, avoiding the memorization of the whole strain or stress history. Damage effects are taken into account within a coupled formulation, following a procedure presented in a previous paper. At this preliminary stage the analysis is performed in two stages (first the heat and mass transfer and then the mechanical analysis) using two FEM computer codes in sequence to apply the proposed approach to structures of any shape. Copyright © 1995 John Wiley & Sons, Ltd