TENAX MS geogrids
Gannett Fleming, Inc.
An employee parking lot, measuring approximately 10.000 m2, is
associated with the premises of the Pennsylvania Employees Credit
Union (PESCU) located in Harrisburg, Pennsylvania. This facility
and the parking lot were constructed in 1987.
Subsequently a large
number of depressions (of various sizes) were observed in the
bituminous concrete pavement pertaining to the parking lot. In
1996, investigations attributed the depressions to the miscellaneous,
uncontrolled fill materials immediately underlying the pavement.
After carefull geotechnic investigation and design, it was recommended
that the bituminous concrete pavement be reconstructed upon a
base reinforced with layers of geogrids. The purpose of the geogrid
was to bridge potential voids, minimize differential settlements,
layers of geogrids were incorporated to reinforce the pavement
foundation for a relatively large parking lot.
TENAX multi-layer geogrids have "more tensile elements"
per unit area. This increased number of tensile elements allows
for more effective interaction with the soil.
The increased interaction
with the soil greatly improves the pull out resistance of the
geogrid in a wide range of soils. TENAX MS 330 geogrid has 3100
tensile elements/m2 compared to 1200
tensile elements/m2 for a conventional
TENAX multi-layer geogrids also have a "variable aperture
size". Multi-layer geogrids are comprised of multiple layers
of high strength extruded, bi-oriented polypropylene grids. The
multiple layers are rolled and stitched together without superimposing
the meshes creating a geogrid with variable sized apertures. The
variable sized apertures greatly improve the geogrid’s interlocking
capacity with the soil.
This is especially true when deploying the typical aggregate fill
used for road construction that has particle size distribution
of 20 mm stone down to fines. The variable sized apertures are
even more beneficial when the project calls for a fill material
that is already on the project site with less than favorable soil
The different size of the openings allows for
better filling of the void spaces in the cross section during
placement of a soil with an extreme soil distribution curve, thus
providing a better interlocking capacity.
The TENAX MS geogrids allowed the construction of a long lasting
and durable road section. The three geogrid layers reinforced
base created a stiff platform highly resistant to traffic loads.