Geogrids are slender structures with normal stiffness but with no bending stiffness (truss elements) used to model soil reinforcements. Geogrids are composed of truss elements with two translational degrees of freedom in each node (u, v). These translational d.o.f. are shared by plane elements and truss elements at nodes. The axial forces in the geogrids are determined in function of the relative axial displacements at the nodes. The formulation of the geogrid element is similar with fully bonded bolt, but because the plane element nodes and geogrid nodes coincide it is not necessary to to make constraint transformations like in the case of bolt elements. The elements may have a plastic behaviour and in this case an element is say to be yielded when the axial force over passed the axial yield strength of the element.
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Fig.37. Geogrid elements (Geotextile). |
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