Residual strain analysis of non-prestressed reinforcement in PPC beams under fatigue loading

Abstract

This paper presents the results of an experimental and analytical study on the residual strain behavior of non-prestressed reinforcement in partially prestressed concrete (PPC) beams under fatigue loading. For the strain measurements, fiber Bragg grating sensors were used. Two beams were initially tested under monotonic loading in order to determine their ultimate load-bearing capacity. Six were tested under fatigue loading conditions. The experimental results show that fatigue failure mode of PPC beams is fracture of the non-prestressed reinforcement. Moreover, residual strain in the non-prestressed reinforcement gradually increases during the fatigue life and the corresponding residual strain evolution can be divided into three stages. Finally, an analytical model for estimating the residual strain of non-prestressed reinforcement in beams is developed. Comparisons of the predicted curves with the experimental data indicate a good agreement. The results of investigation in this paper furnish the experimental basis for the fatigue design and analysis of PPC beams.