Nonlinear Analysis of Two-Dimensional Problems in Concrete Creep

Abstract

This paper deals with the analysis of plane and axisymmetric problems with concrete-like material behavior where nonuniform transient temperature fields and time-dependent cracking are considered. The material is treated as an aging viscoelastic isotopic substance characterized in its uncracked state by the constant Poisson’s ratio and the uniaxial creep function which is shown to obey an extended form of the time-temperature shift. A cracking criterion is postulated whose ingredients are a failure surface expressed in terms of principal strains and an interactive curve which takes stresses and strains into account. The stress-strain relations are formulated for discontinuous material behavior permitting crack formation in three orthogonal directions with arbitrary crack histories. The numerical analysis is obtained within the framework of the finite-element method and a step-by-step integration procedure. The method is applied to a concrete model and comparisons between analysis and experiment are given.