Tensile properties of geogrids under cyclic loadings

The tensile behavior of three commonly used polymeric geogrids (polypropylene, polyester, and high-density polyethylene) under cyclic loading was investigated. The tests were strain controlled and were conducted for 100 cycles at different load ratios. The stiffness and damping ratio of geogrids at all load cycles were compared with the primary loading curve. The stiffness increased while the damping ratio decreased with more loading cycles at any load ratio. A higher load ratio decreased the stiffness ratio and increased the damping ratio. The strengths of prestressed and virgin specimens were also compared. Negligible strength reduction resulted from short-term cyclic loading. The strength obtained from static tests appears reasonable when used for design considering short-term cyclic loading. An empirical relationship is proposed to determine the strain accumulated from cyclic loading under different load ratios.