Performance Properties of Geogrids - Reinforced Soil Engineering: Advances in Research and Practice - page 34

the design strength in a proper way, fully in accordance with the meaning of the
standards like BS 8006. Alternatively, the designer must list the applicable
material factors to be used with the different polymers, and the supplier has to
prove properties of the products for verification by the site engineer.
The manufacturers should supply the appropriate stress-rupture line and
certification of the partial factors applicable for the stated design conditions.
Alternatively, they should supply independently verified test reports for the site
conditions mentioned. Requirements for material or extrapolation factors must be
clearly specified.
Further, the stiffness must be specified in the form of a strain requirement
either as maximum level after a certain lifetime or as a maximum value during
construction together with a maximum value for creep during a certain number of
years after construction.
When specifications are compiled in this way, there need not be 199
discussions about applicability and product specific parameters. Instead, a
straightforward calculation can be made to prove whether or not a product fulfills
the design requirements. Thus, competition between the products will be used to
maximize the benefits for designers and contractors alike.
REFERENCES
AASHTO-AGC-ARTBA. Design guidelines for use of extensible reinforcements for
mechanically stabilized earth walls in permanent applications. Task Force 27
Report, 1989.
TM Allen, R Bathurst. Characterization of geosynthetic load-strain behavior after
installation damage. Geosynth. Int. 1(2): 181-199, 1994.
BBA CERTIFICATE No. 97/R096, Road and Bridges Agr´ment Certificate for
FORTRAC Geogrids. British Board of Agr´ment, UK, 1997.
BS 8006, Code of Practice for Strengthened Reinforced Soils and Other Fills. British
Standardization Institute, 1996.
G den Hoedt, W Voskamp, CJM van der Heuvel. Creep and time-to-rupture of polyester
geogrids at elevated temperatures. Proceedings 5th International Conference on
Geotextiles, Geomembranes and Related Products, Singapore. 1994, Vol. 3,
pp 1125-1136.
RA Jewell. Strength and deformation in reinforced soil design. Proceedings 4th
International Conference on Geotextiles, Geomembranes and Related Products, The
Hague, 1990a, Vol. 3, pp 913-947.
RA Jewell. Revised design charts for steep reinforced slopes. Reinforced Embankments.
London: Thomas Telford, pp 1-30, 1990b.
RA Jewell, JH Greenwood. Long-term strength and safety in steep soil slopes reinforced
by polymer materials. Geotext Geomembr. 7(1&2): 81-118, 1988.