Within an international cooperation between the Perm National Research Polytechnic Uni-versity, Russia and the Magdeburg-Stendal University of Applied Sciences in Germany the behavior of geogrid and steel grid material during pullout tests were analyzed. The tests were carried out using a pullout test box with several geogrid and geosynthetic materials. Further tests were done with steel grid material. The aim was to verify the pullout characteristic of steel grids in comparison to geogrids.
The tests of the steel grid are significant because in many countries steel grids are used for reinforcement applications and are so in direct competition to geogrids.
The tests were carried out in two ways. First tests were done according to the regulations in EN 13738 and DIN 60009. These tests results were compared with the results of so called “staged pullout tests”. These are tests where the normal stress will be increased in several steps while the geogrid or steel grid material will remain in the box. So the test can be carried out without any influence from removing the fill material, different compaction grades or water contents.
In our tests we could show that steel grids and geosynthetics have different performances on pullout re-sistance. We could evaluate that the pullout resistance depends on the relationship between the grain size and the mesh grid size of the grid material. And last but not least we were able to evaluate that multi-step tests are suitable to find the pull out resistance of grid materials.
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