Buckling of One-Way High-Strength Concrete Panels: Creep and Shrinkage Effects

Abstract

A nonlinear theoretical model is developed in this paper for investigating the time-dependent behavior of one-way high-strength RC panels, with particular emphasis on the combined effects of creep and shrinkage on the buckling capacity and its degradation with time. A rheological generalized Maxwell chain model is used for modeling the creep of the concrete including its cracking, tension stiffening, and aging through strain- and time-dependent springs and dashpots. The incremental governing equations of the panel are derived and solved through a step-by-step time analysis that takes into account the variation of the internal stresses and deformations with time. A smeared cracking model is adopted, and an iterative procedure is conducted at each time step for the determination of the unknown rigidities of the cracked section, as well as the length of the cracked region. The capabilities of the proposed model are demonstrated through numerical and parametric studies, which show the important roles of creep and shrinkage in the buckling of high-strength concrete panels and which reveal the sensitivity of the nonlinear response to the magnitude and eccentricity of the sustained load and to the reinforcement ratio.