BEHAVIOR OF GEOGRIDS UNDER CYCLIC LOADS

This paper deals with the mechanical behavior of two geogrids in high density polyethylene and polyester for soil reinforcement applications. The behavior has been investigated by means of cyclic tensile tests conducted at different frequencies and load ratios for a duration up to 10,000 cycles. The above tests allowed the definition of the geogrid tensile properties under cyclic loads, such as the unload-reload tensile modulus and damping characteristics. The test results allowed the definition of a method to predict the geogrid behavior that will be useful for future programmed test series in interaction with soil. Pre-stressed cyclic tests have been performed by means of tensile cyclic tests performed at relatively high frequencies with loads ranging around the long term design loads of the geogrids. The described testing methodologies and results are a valuable tool for qualitative prediction of the behavior of a geogrid when subject to repetitive loading such as traffic, train loading and earthquakes.