Roadway Design

Patent-Pending Advancement for Roadway Design

This innovative patent-pending precast counterfort system is designed to support future embankment consisting of existing clay/soil backfill. The system includes a precast concrete Base and a precast concrete Face with integral Counterforts (Face/CF). The Base will extend in front of the Face/CF (Base Toe) and also extend rear-wards past the end of the Counterforts (Base Heel). The Base Toe/ Heel will increase to engage more soil as you start increasing in retained height to provide adequate stability for the wall.

Low-strength material will be pumped under the Base to ensure proper bearing on the foundation soils underneath. High-strength grout will be utilized at the shear key and joints between the Base and Face/CF to mechanically fasten the two sections together with use of cast-in bar anchors. The Face and the majority of the Base will span horizontally across the Counterforts minimizing the stresses within the sections. The implementation of the Counterforts dramatically increases the lever arm, therefore reducing the stresses in the moment connection between the Base and Face/CF. These both attribute to a more efficient design of the retaining wall system.

Design Codes

The counterfort wall system is designed in accordance with American Railway Engineering and Maintenance-of-Way Association (AREMA), American Association of State Highway and Transportation Officials (AASHTO) and State Department of Transportation (DOT) codes, based on load resistance factor designs with service level checks where required by code.

Site Analysis

It is the responsibility of the owner (or their representative) to provide a geotechnical report that includes asite analysis with the following components:

  • Recommended Ultimate Factored Bearing Capacities adjusted accordingly along proposed wall layouts for varying wall heights and site conditions
  • Global Stability
  • Settlement Concerns
  • Remediation Recommendations

Information Required for Design

  • Geotechnical report (see Site Analysis)
  • Project specifications
  • Existing and proposed grading of the site
  • Proposed plan and elevation of the wall
  • Surcharge loads on the wall (such as traffic, shoulder slabs, barriers, buildings, etc.)
  • Typical cross section showing the wall and the roadway structure above
  • Proposed and Existing Drainage and Utility Plans and Elevations