Fatigue strength control of flexural reinforced concrete members

Abstract

The article compares approaches to fatigue effect assessment using standard methods of calculating the strength of reinforced concrete members under the action of bending moments and longitudinal forces. A numerical experiment was carried out using the probabilistic forecast of the change in the strength of variously reinforced beams after cyclic effects of moderate intensity. The calculations performed according to ultimate force methods and nonlinear deformation models are provided using statistically representative experimental data on the concrete strength and deformation properties prior to and following 50 cycles of mechanical impacts with a 0.8 amplitude and zero asymmetry. Two series of concrete prismatic samples (100 × 100 × 400 mm) were tested. The Instron 5989 complex was used for automated loading of samples with the constant deformation rate and continuous recording of controlled parameters along all directions. A numerical experiment was conducted for beams of a rectangular cross-section (b × h = 100 × 200 mm) with a various level of one-sided reinforcement (А400, µ = 1–6%). It is established that predicting and controlling the effects of fatigue processes should be carried out using the criteria of nonlinear deformation models.