204Geogrid Reinforcement of Embankment and Slopes and Subgrade

204.01 Description. This work shall consist of furnishing and installing geogrid for

reinforcement of embankment slopes and/or subgrades as shown on the plans and in conformance with these specifications.

204.02 Material Requirements. The geogrid shall meet the requirements of Subsection

714.15.

204.03 Construction Requirements.

204.03.1 Preparation of Design Grade of Geogrid.

204.03.1 1--Preparation of Foundation Soil . An embankment site that is to receive

geogrid reinforcement upon the foundation soil shall be cleared and graded to establish a relatively smooth surface. Trees and stumps are to be cut off at the ground line and sawdust or sand placed over these areas to provide a cushion for the geogrid.

204.03.1 2--Preparation of Basement Soils . An embankment that is to receive geogrid

reinforcement located within the basement soil portion of the embankment shall be brought up to the proper grade as shown on the plans and compacted to the required density. The surface shall be left rough so as to provide for a good bond with the next embankment lift above the geogrid.

204.03.1 3--Preparation of Design Soils or Subgrades . A design soil or subgrade that

is to receive geogrid shall be shaped an d compacted to the required density thus providing a smooth finish, free of loose material and sharp objects.

204.03.2 Geogrid Installation . Geogrid shall be placed coincidently with the

compacted lift nearest the design elevation shown on the plans. No partial or half-lift thicknesses are required; however, at no time shall the placement elevation deviate by more than one foot from the design grade. Correct orientation of the geogrid shall be verified by the Engineer. Geogrid shall be secured in-place to prevent movement while being covered.

204.03.3 Overlaps and Joints.

204.03.3 1--Uniaxial Geogrids. Uniaxial geogrid sha ll be placed in continuous

longitudinal strips in the direction of main reinforcement and adjacent strips do not need to be overlapped. However, if the Contract or is unable to complete a required length with a single continuous length of geogrid, a joint may be made with the Engineer's approval. This joint shall be made for the full width of the strip by interlacing over and under the main reinforcing strands using a solid rod or hollow pipe of similar material and strength. No end joints will be allowed in any two adjacent strips or within 10 feet of the face of the embankment or, in the case of a spill through slope, in front of the abutment. In the event that the length of geogrid reinforcement is greater than the roll length, then end joints will be allowed in adjacent strips, but they cannot be within 75 feet of one another as measured along the length of the strip. Every effort should be made to