Supporting Infrastructure with HDPE Geogrid on the South Fraser Perimeter Road Project with MSE/RSS

This paper will focus on the array of retaining walls and slope systems utilized on this recent 40
km section of new four-lane expressway along the Fraser River in the Province of British
Columbia.

The author intends to visually share the diverse applications where the unique advantages of
high-density polyethylene (HDPE) have been utilized specific to this project in the following
structures.

• Temporary Preload Walls Constructed Well In Advance of the Prime Construction Works
• Mechanically Stabilized Earth (MSE) Approach Walls
• Two Stage Piled Abutment Walls Involving False Fascia Precast
• Reinforced Soil Slopes (RSS) as Sustainable Green Slopes
• Unique Grade Separations With Uneven Soil Reinforcement Lengths In Steep Terrain
• MSE/RSS Applications At Culvert Structures
• Unique Combination Wall Involving a Load Transfer Platform

“Designing with Geosynthetics” as a soil reinforcement material for bridge supporting structures
exists as an acceptable design methodology within the American Association of State Highway
and Transportation Officials (AASHTO), as well as the Federal Highway Administration (FHWA).
The use of HDPE geogrid on such projects as the SFPR provides many benefits to stakeholders
making decisions on publically funded infrastructure. Benefits associated with the use of HDPE
geogrid will be briefly illuminated for the audience with respect to the following design
considerations.

Integration of Sustainable Structures (RSS) as encouraged by our professional

• associations.
• Advantages of HDPE soil reinforcement in aggressive environments (i.e. Chlorides and

pH).

This highway alignment has the additional challenge of poorer bearing soils as it is proximal to
the foreshore of the Fraser River and Burns Bog, coupled with the demanding seismic
requirements typical of this region. The benefits of HDPE in this design environment will be
briefly discussed.

The paper will provide a brief background on design methodology, and the ability to tolerate
settlement in poor soils, which ultimately resulted in an improved construction schedule in the
overall earthworks program for this project.