View the article online for updates and enhancements. Abstract. The investigation was conducted to study the fatigue behavior of steel fiber reinforced high-strength concrete (SFRHSC) beams. A series of 5 SFRHSC beams was conducted flexural fatigue tests at different stress level of 0.5, 0.55, 0.6, 0.7 and 0.8 respectively. Static test was conducted to determine the ultimate static capacity prior to fatigue tests. Fatigue modes and S-N curves were analyzed. Besides, two fatige life prediction model were analyzed and compared. It was found that stress level significantly influenced the fatigue life of SFRHSC beams and the fatigue behavior of SFRHSC beams was mainly determined by the tensile reinforcement.
IntroductionIn practical engineering, a large number of structures such as bridge decks, offshore installations and airport runaways often bear cyclic loads. These loads such as wind loads, and wave loads could result in progressive and continuous micro cracks, which leads to the increased permanent strains and decreased stiffness of the structure. The fatigue failure will eventually occur by the damage. Therefore, considerable interest has been developed on the fatigue performance of the concrete structures. The mechanism of fatigue in concrete can be divided into three distinct stages. The first stage is termed as flaw initiation and involves flaws forming within weak regions of the concrete. The second stage is known as micro cracking and is featured by slow growth of flaws to a critical size. The third stage occurs when a continuous macro cracks form, eventually leading up to the final failure [1]. The first and third stage make up approximately 10% of the total curve separately, while the second stage accounts for the remaining 80% [2]. The addition of fiber reinforcing can increase the fatigue performance of the concrete under flexural fatigue loading and explained that the fibers would be able to bridge cracks and prolong fatigue life under tensile forces [3]. The effects of the fiber content, fiber aspect ratio and notchto-depth ratio on the concrete fracture and fatigue behaviour were studied, and the fatigue strengths of SFRC beams were calculated. According to the regression technique, some empirical formulas for predicting the fatigue strength of SFRC beams were also suggested [4]. 11 beams reinforced by a new kind of steel (20 MN Siv) under static loading and fatigue loading with constant amplitudes were tested and the calculation method of concrete strain on the edge of compressive zone and the tensile stress of longitudinal reinforcements was put forward [5]. Fatigue test of RC beams was conducted, and the conclusion was that the mode of failure was related with stress level. In low stress level, fatigue specimens broke in the mode of bending failure with the sign of brittle fracture of reinforcement, and in