Deformation of concrete under high-cycle fatigue loads in uniaxial and eccentric compression

This paper studies the deformation evolution of concrete under high-cycle fatigue loads. First, uniaxial and eccentric compressive fatigue loads were exerted on prism concrete specimens to observe the mechanical properties of concrete under fatigue loading. Fatigue tests showed that elastic modulus does not always decrease, but strains always increase as loading cycles accumulate. Moreover, strains on the cross-section of each eccentrically fatigued specimen always maintain linear distributions. Based on these experimental findings, a simplified constitutive model for concrete under high-cycle fatigue loads was adopted; hence, a fatigue deformation prediction model was developed to analyze the strain and stress distributions on a cross-section under both cyclic axial forces and bending moments. The proposed model demonstrated its validity by predicting fatigue deformations in good agreement with experimental results. Finally, based on the new prediction model, a case study was conducted, which found that fatigue could pose a big influence on the long-term deformation of concrete bridges.