Specification Part 3 - Road & Bridge Works - Urban Administration ...

704.5 Rates
The contract unit rate for the accepted quantities of geotextile in place shall be per square. The rate is
full compensation for furnishing, preparing, hauling, and placing materials including all labour, material,
freight, tools, equipment, and incidentals to complete the work to these Specifications.
705 GEOGRID APPLICATIONS FOR REINFORCED SOIL SLOPE PROTECTION
705.1 Description: This work shall consist of constructing a reinforced soil slope in
accordance with the contract documents and as directed by the Engineer. The Contractor shall provide
all labour, equipment, and materials for and incidental to site preparation, furnishing, installing, and
backfilling geogrid reinforcement as indicated.
705.2 Material
Geogrid reinforcement: The geogrid reinforcement for primary slope stabilization shall be uniaxially
oriented grid structure. The geogrid reinforcement for secondary slope stabilization shall be a biaxially
oriented grid structure. The manufacturer shall furnish the Engineer with test reports certifying that the
product meets the requirements of these Specifications. Un-iaxail and bi-axaial geogrid shall be regular
grid structure. The geogrid shall have high resistance to deformation under sustained long-term design
load while in service and shall be resistant to ultraviolet degradation, damage under normal
construction practices and all forms of biological or chemical degradation normally encountered in the
material being reinforced. The long term allowable tensile strength shall have the minimum value of
156.6 kN/m. The minimum pull-out resistance factor shall be 0.42 as determined by ASTM D 6706.
Backfill: The contractor shall provide select granular backfill material as per contract.
Facing: The contractor shall provide stone fill and geotextile as facing for the reinforced soil slope to
the lines and grades shown on the plans.
705.3 Installation
All areas immediately beneath the installation area for the geogrid shall be properly prepared as
detailed on the plans and as per these Specifications or as directed by the Engineer.
The geogrid shall be installed in accordance with the manufacturere’s recommendation. The geogrid
shall be placed within the layers of the compacted soil as shown on the plans or as directed by the
Engineer. If the contractor is unable to complete a required length with a single continuous length of
geogrid a joint may be made with the approval of the Engineer. After the specified layer has been
placed in its entirety and compacted, the next geogrid layer shall be installed in its entirety. The process
shall be repeated for such subsequent layer of geogrid and soil. Geogrid reinforcement shall be placed
to lay flat and pulled tight prior to backfilling . After a layer of geogrid has been placed , suitable means,
such as pins or small piles of soil shall be used to hold geogrid in position until the subsequent soil layer
can be placed. Under no circumstances shall a track type vehicle be allowed on the geogrid before at
least 150mm of soil has been placed.
Backfill placement: Backfill shall be compacted as specified by project specifications or at least 95
percent of the maximum density determined in accordance with IS:2726 (Part-8), whichever is greater.
Backfill within 900 mm of slope face shall typically be compacted with hand equipment. Fill shall be
placed in 200 mm maximum lift thickness.
705.4 Measurement and basis of payment : The quantity of special provision to be
measured for payment will the number of square meters of geogrid installed in the complete and
accepted work.
705.5 Rates
The Contract unit rate will be full compensation for furnishing and installing the specified materials in
accordance with the contract documents including on-site supplier representation, site preparation,
geosynthetics reinforcement and backfill and for furnishing all labor, tools equipment and incidentals
necessary to complete the work to these Specification.