Geogrids

Geogrids

Solution Overview

A geogrid consists of a 2-dimentional arrangement of integrally connected tensile elements or ribs, that form a grid or net-like structure, usually supplied in roll form. Manufactured from polymers, geogrids are classed as geosynthetic products; this is a broad product classification that includes geotextiles and geomembranes alongside other minor categories.

Tensar geogrids are typically manufactured from oriented high-density polyethylene (HDPE) or polypropylene (PP) for durability, stiffness and strength. The junctions between ribs are integrally formed giving them high strength and structural stability

Geogrids are used to solve civil and geotechnical engineering problems in or on the ground. They primarily provide a stabilisation or reinforcement function, to add to or enhance the properties of soil or aggregate materials

What are the functions of a geogrid?

Geogrids primarily provide a stabilisation or reinforcement function, to enhance the performance of soils. They also provide separation between soil and aggregate layers.

How do geogrids stabilise?

The openings or apertures between ribs allow aggregate to strike through and interlock with the geogrid. Provided the geogrid is stiff enough and the junctions strong enough, the aggregate is confined within the apertures forming a new geogrid/aggregate composite material with improved strength and resistance to deformation.

How do geogrids reinforce soils?

For soil reinforcement applications, load must be transferred between the soil and the geogrid.   The transverse ribs uniaxial geogrids provide an efficient mechanism for load transfer by abutment rather than friction alone. The high tensile load in the geogrid is carried by the longitudinal ribs. They must be capable of sustaining such high loading for the full life of the structure (often up to 120 years), requiring durability and long term strength and stiffness.

Comparing Geogrids

The efficiency of the interlock and confinement provided by a geogrid is dependent upon its physical characteristics (in-plane stiffness, junction efficiency, rib profile) and compatibility with the aggregate (particle size and type). Different geogrids with the same short term QC strength can have widely different characteristics dependent up the method of manufacture, the joint type, rib profile and polymer used.

For soil reinforcement applications, the geogrid must have proven long-term strength and stiffness characteristics as well as high durability. Geogrids vary in their long-term characteristics, dependent upon the manufacturing methods and the polymer used. Tensar uniaxial geogrids are certified for 120 year design life in a wide range of soil pH and chemically aggressive environments.

Free-Draining Separation Barrier

Testing and experience have shown that Tensar geogrids support the function of separation when properly graded aggregate fill is used. Geogrids are not prone to “blinding out” or clogging which may occur with a geotextile used as a separation layer.

Trenching with geogrid

Tensar geogrids are routinely excavated through and punched through in order to place underground utilities.