Multiscale random fields-based damage modeling and analysis of concrete structures

This paper provides a new approach to incorporating the stochastic nature of damage constitutive relations in the finite-element analysis of concrete structures. Within the framework of stochastic damage mechanics, the spatial variability of concrete was modeled as a two-scale stationary random field. At the microlevel, the damage evolution law of concrete was mapped to a random field corresponding to the microscopic fracture strain. At the macrolevel, the strength distribution of any concrete component forms a lognormally distributed random field. The connection between the two-scale random fields was established by a covariance constraint such that the scale of fluctuation of the random material property was satisfied in both scales. Taking advantage of the stochastic finite-element method, both the microscopic random damage evolution of concrete and the fluctuation of macroscopic structural responses can be numerically represented. Stochastic structural modeling and damage analyses for a conventional cantilever beam and a plane frame were carried out to illustrate the proposed method.