The current study examines the effect of steel fiber content on the uniaxial compressive response of lightweight concrete to propose a stress-strain model in cyclic loading. For this purpose, 150 x 300 mm cylindrical specimens containing different volume ratios of steel fiber (0, 0.5, 1, and 1.5%) were tested to plot the cyclic curves of steel fiber-reinforced lightweight aggregate concrete (SFRLWAC). The best combination of two types of steel fibers was used in this research: straight hooked-end and crimped fibers with aspect ratios of 50 and 28.5, respectively. Key points on cyclic curves were examined, and the compressive behavior of lightweight concrete was investigated. The results show that the integration of steel fibers reduces the plastic strain and stiffness degradation of the reloading paths. Furthermore, a rise in steel fiber volume fraction is associated with increased common-point coordinates. A stress-strain relationship was proposed to define the compressive cyclic behavior of SFRLWAC. The model was compared with the experimental findings to confirm its validity. The proposed model shows satisfactory agreement with the experimental results.
