TriAx geogrids

TriAx geogrid - Tensar invented and pioneered the original biaxial form of geogrid – until now the geogrid with the best performance in trafficked applications.

Through the Tensar policy of continual product development and innovation, the challenge for the Tensar development team was to improve on the biaxial geogrid and achieve even greater, long-term performance benefits.

By examining all the design characteristics of the biaxial geogrid, through testing and research, the development team was able to identify the key areas that affect its performance. These are: the profile of the rib section, rib thickness, junction efficiency, aperture size and, of particular importance, in-plane stiffness.

This research led to a revolutionary change from the rectangular to the triangular form of the geogrid. This fundamental change to the grid structure, coupled with an increase in the rib thickness and junction efficiency, gives greatly improved aggregate confinement and interaction, leading to improved structural performance of the mechanically stabilized layer.

This was a real revolution in the geogrid technology with significant, new and improved benefits over the biaxial geogrid. A series of rigorous tests followed comparing the functional performance of TriAx with Tensar biaxial grids. These tests confirmed the research effort and demonstrated that TriAx out-performed the best performing of biaxial geogrids.

The advantages of TriAx geogrids compared with biaxial geogrids

The unique TriAx structure incorporates several characteristics which combine to create an optimised structure that out-performs conventional biaxial geogrids in trafficking applications. When combined with a suitable aggregate TriAx produces a mechanically stabilized layer with exceptional performance.

1.Load distribution

The load’s distribution after installation is three-dimensional and acts radially at all levels in the aggregate. For a stabilized layer to be effective it must have the ability to distribute load through 360 degrees. A really multi-directional product with near isotropic properties.

2.Multi-directional properties

Biaxial geogrids have tensile stiffness predominantly in two directions. TriAx geogrids have three principal directions of stiffness, which is further enhanced by their rigid triangular geometry. This produces a significantly different structure than any other geogrid and provides high stiffness through 360 degrees. A really multi-directional product with near isotropic properties.

3.Junction integrity

TriAx geogrid is produced from an extruded sheet of polypropylene. This is then punched with an array of holes and stretched to create the unique TriAx structure. This Tensar process coupled with the design of junctions results in a product with high junctions strength and stiffness.

4. Proven importance of rib profile

TriAx geogrids have greater rib depth compared with conventional biaxial geogrids. Trafficking tests and analytical modelling were undertaken to compare performance advantages between the two forms of geogrid with various rib depths in a mechanically stabilized layer. The results were conclusive in confirming that an improved structural performance was achieved with the TriAx geogrid and its deeper rib depth and unique profile. Numerical modelling techniques confirm the importance of geogrid thickness on aggregate confinement and load dissipation.

The structure of Triax rib directly influences the efficiency of the stabilized layer

5. Installation and handling

The final aspect of the performance is handling on-site. Extensive use in projects covering a range of applications have now proved that TriAx is easy to handle, is robust and tough enough to be installed over weak subgrades.

TriAx geogrid can be handled by mechanized equipment or carried by two men.

TriAx geogrid is unrolled on site.

The aggregates are placed over TriAx geogrid prior to full compaction.


TriAx geogrids from Tensar International offer exceptional performance in ground stabilization and sub-base reinforcement. Combined with the technical support and expertise offered by Tensar team, TriAx represents the future of geogrid technology and due to its proven performance will replace the conventional biaxial geogrids.

Roads, motorways and trafficked areas

With TriAx geogrid and its structural performance benefits, there is an opportunity to make considerable savings on unpaved roads and permanent road construction.

Less aggregate is required with TriAx geogrid, which also reduces installation time and further helps to reduce ground stabilization costs. The reduction in aggregate materials and transport also helps engineers meet sustainability objectives.

For thin surfaced pavements, TriAx geogrids provide longer-term benefits, with an increase in pavement life and reduction in whole life costs.


Increasingly, housing developments are being built on weak or marginal lands. This means variable subgrade conditions which leads to differential settlement. By providing a reinforced sub-structure to a road pavement, TriAx geogrids can be used to help control differential settlement and offer cost saving up to 75% compared to conventional solutions.

Spanning voids

TriAx geogrids can be used for protection against sinkholes and subsidence problems, such as those encountered in areas of abandoned mine workings and can help top provide indications of voids developing before the surface. All geogrid applications require appropriate engineering analysis by Tensar Design Engineers or other qualified professional engineers.

TriAx represents the future in the geogrid technology, replacing the conventional biaxial geogrids.


Case study. Windfarms. Fantanele-Cogealac