Tensar Technologies Limited

Tensar International Corporation

Anthony Thomas Walsh

A multi-axial geogrid possesses a series of interconnected strands or ribs that are arranged along at least two different axes within the plane of the structure. The strands or ribs have an aspect ratio, defined as the ratio of the thickness to width, of greater than 1.0, thickness being the direction normal to the plane of the structure. The geogrid can be manufactured by modifying the process parameters in order to create high aspect ratio ribs, using any of the various known methods for producing geogrids. A reinforced civil engineering structure, and method therefor, is formed by embedding in soil one or more horizontal layers of geogrid having high aspect ratio ribs. The reinforced structure shows improved rutting performance when subjected to vehicular traffic.

Multi-axial grid or mesh structures with high aspect ratio ribs

A one-piece plastics material mesh structure, particularly a geogrid, is produced by stretching a plastics sheet starting material formed with an array of holes and comprises a plurality of generally parallel rib structures extending longitudinally in a first direction parallel to the stretch direction and a plurality of generally parallel bar structures extending in a second direction transverse to the rib structures. The rib structures and said bar structures are interconnected by junctions. The rib structures have rib segments oriented in the first direction along their lengths and orientation in this direction extends across the junctions connecting two such oriented rib segments. The bar structures are such that their overall stretch ratio in the second direction is a maximum of 1 and all locations along the length of the bar structures have a maximum orientation of 1.5 in the second direction.

Mesh structure, production and uses thereof

To make an oriented plastics material geogridin which oriented strandsform triangular meshes with a junctionat each corner and six of the strandsmeet at each junction, a plastics material sheet starting materialhas holesin an array of hexagons, opposite holesof each hexagon being aligned in the machine direction, and the starting materialis stretched first in the machine direction and secondly in the transverse direction. In the eventual geogrid, the centre portions of the hexagons in the starting materialform the junctions. The centres of the junctionsare slightly biaxially oriented, but at the edges of the junctions, the orientation of the edge of substantially each strandorruns around the edge of the respective junctionand into the edge of the next strandor. During the second stretch, restraint can be applied in the first stretch direction and discontinued before the material is allowed to relax in the second stretch direction. If desired, the procedure can be terminated after the first stretch, to produce a uniaxially-oriented geogrid. By using a starting materialwhich has through holesand weakened zones, it is possible to form the geogrid of the invention from a starting materialhaving a rectangular array of through holes

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Lancashire, United Kingdom

Anthony Thomas Walsh