Abstract
One of the main uncertainties in the design of permanent reinforced soil structures is the strength and deformation characteristics throughout the design life of polymeric reinforcement under load in the backfill. The current design practice focuses primarily on the creep deformation and the design tensile rupture strength is determined by using a relatively large creep reduction factor. To have a better insight into the time-dependent strength and deformation characteristics of polymer geogrid, in total 34 creep and stress relaxation tests were performed at various tensile load levels, each lasting for 24 hours, by using polypropylene (PP), polyester (PET) and high density polyethylene (HDPE) geogrids. A series of constant rate of strain (CRS) loading tests was performed on specimens that had been subjected to creep or relaxation loading. The tensile strength after creep and relaxation loading of each geogrid was essentially the same value as the one obtained from a monotonic CRS tensile loading test before the creep or stress relaxation test. This result shows that it is not necessary to use a creep reduction factor when determining the design tensile strength for prototype reinforced soil structures subjected to seismic force.
