Section 2: Retaining Wall Layouts

General Content Layout

In general, retaining wall layouts include the following information.
  • Plan View. Include the following in the plan view:
    • Beginning and ending wall points by station, offset, and roadway alignment
    • Additional points as necessary to describe the relationship of wall alignment to roadway alignment(s)
    • Indication of which side is the face of the wall
    • Horizontal curve information if applicable for wall alignment
    • Location of soil borings (Include boring name, station, offset, and top-of-hole elevation.)
    • Signing, lighting, etc., mounted on or passing through wall (Designate and locate the sheets that contain information for these elements.)
    • Surface and subsurface drainage structures or utilities that could affect or be affected by wall construction (Designate and locate the sheets that contain information on the structure or utilities.)
    • Limits of temporary special shoring
  • Elevation view. Include the following in the elevation view:
    • Existing ground line along wall alignment
    • Proposed finished grade line at face of wall
    • Bottom of wall for payment
    • Top of retaining wall grade line (Does not include the top of rail.)
    • Soil boring information where possible, shown at the correct elevation and scale
    • Designation for “Back Face of Wall” when back of wall is shown
    • Panel numbers when applicable
    • Drainage structures and features including slope at flowline, sizing, and maintenance recommendations within contract notes
    • Utilities, signing, lighting, etc., as noted above
  • Estimated quantity table. Include the estimated quantity table for each retaining wall type. Refer to a specific wall type for list of bid codes. Include the following in the estimated quantity table:
    • Area of retaining wall
    • Linear footage of railing on wall
    • Miscellaneous quantities associated with wall (riprap, etc.)
  • Typical section. A typical section should contain the following information:
    • Cross section showing the relationship of the wall to the roadway
    • Control point for horizontal and vertical alignment, typically shown at the top outermost corner of the wall
    • Indication of maximum slope on top of and in front of wall
    • Location of proposed finished grade
    • Railing type, flume, mow strip, etc., if applicable
    • Distance from back of wall panel to face of abutment cap, if applicable
  • General notes. Include the following in the general notes:
    • A note stating the required wall embedment depth if the specified embedment is greater than 1 ft. for slopes up to 4:1 in front of wall or 2 ft. for slopes in front of wall that are steeper than 4:1, as well as a note stating that the wall is measured between top of wall and "X" ft. below finished grade
    • Reference to all applicable standard sheets for pertinent information
    • Other pertinent information regarding wall design and construction
    • Foundation design criteria (nominal bearing resistance, resistance factor and others)

Plans for Specific Wall Types

For specific retaining wall types, include the following additional information on the layout and in the plan set.
Spread Footing Walls
. For spread footing walls, include the following additional information:
  • Panel design designation (for example, LC-10-32) for each panel corresponding to the appropriate cast-in-place spread footing wall standard sheet. The designation includes a reference to the controlling standard drawing, design height, and panel width information.
  • Location of expansion and construction joints (Assuming 32-ft. panels, every third joint is typically designated as an expansion joint.)
  • Set bottom of wall (top of footing) horizontal and stepped to meet minimum embedment criteria. (Distance from one step to the next is typically greater than 6 in. Provide bottom of wall elevations for all panels.)
  • Appropriate standard sheets pertaining to cast-in-place spread footing walls. Select appropriate standard design case based on available surcharge and slope condition. Limit wall height to maximum of 20 feet as per standard. Wall height more than this limit will require custom design and approval from the Department.
Designate all information necessary for the contractor to construct the wall on retaining wall layouts for spread footing walls. This type of wall does not have a proprietary vendor to provide shop drawings, so the plan set must be complete with details.
Mechanically Stabilized Earth (MSE) Walls
. For MSE walls, include the following additional information:
  • Bottom of wall shown following the proposed finished grade offset at the minimum embedment depth specified
  • Appropriate standard sheets pertaining to MSE walls (e.g., RW(MSE)DD – Mechanically Stabilized Earth Retaining Wall Design Data)
Concrete Block Walls
. For concrete block walls, include the following additional information:
  • Bottom of wall shown following the proposed finished grade offset at the minimum embedment depth specified
  • Appropriate standard sheets pertaining to concrete block walls (e.g., RW(CB)DD sheet)
Tied-Back Walls
. For tied-back walls, include the following additional information:
  • Type, location and spacing of tied back anchors
  • Bar dimension, incline angle, and material grade
  • Drill hole diameter, minimum bond length requirements, and corrosion protection measures
  • Panel and closure-pour width dimensions
  • Bottom of wall shown with a level footing elevation, also referred to as having steps. (Distance from one step to the next is typically greater than 6 in.)
  • Performance load test requirement
Designate all information necessary for the contractor to construct the wall on retaining wall layouts for tied-back walls. This type of wall does not have a proprietary vendor; however, shop drawings are required to fully detail the panel schedule to be used on the project and information regarding proposed anchor length.
Soil/Rock Nailed Walls
. For soil or rock nailed walls, include the following additional information:
  • Location of expansion and construction joints spaced at intervals not to exceed 90 ft.
  • Set bottom of wall horizontal and stepped to meet minimum embedment criteria. (Distance from one step to the next is typically greater than 6 in. Provide bottom of wall elevations for all panels.)
  • Estimated quantity for “Soil/Rock Nail Anchors”
  • Typical section showing existing or proposed foundations or other obstructions that may interfere with wall construction
  • Test nail lengths, loads, and quantities
  • Nail incline angle, bar grade and size, and corrosion protection measures
  • Wall facing and nail head connection
  • Reinforcement details and shotcrete thickness
  • Proof and verification load test requirements
Designate all information necessary for the contractor to construct the wall on retaining wall layouts for nailed walls. This type of wall does not have a proprietary vendor to provide shop drawings, so the plan set must be complete with details.
Drilled Shaft Walls
. For drilled shaft walls, include the following additional information:
  • Set bottom of wall horizontal and stepped to meet minimum embedment criteria
  • Panel width dimensions and concrete closure pour connection
  • Provide cap, stud anchor connection detail sheets including closure pilaster if any
  • Bottom of wall shown with a level footing elevation, also referred to as having steps. (Distance from one step to the next is typically greater than 6 in. Provide bottom of wall elevations for all panels.)
  • Estimated quantity for “Drilled Shaft” used on wall (This quantity is broken into specified shaft diameters.)
Designate all information necessary for the contractor to construct the wall on retaining wall layouts for drilled shaft walls. This type of wall does not have a proprietary vendor to provide shop drawings, so the plan set must be complete with details.
Temporary MSE Walls
. For temporary MSE walls, include the following additional information:
  • Bottom of wall shown following the proposed finished grade offset at the minimum embedment depth specified
  • Appropriate standard sheets pertaining to temporary MSE walls (including RW(TEW)DD sheet)
Reinforced Soil Slope
. For reinforced slopes, include the following information in additional to applicable retaining wall general content layout:
  • Bottom and top of existing slope following the proposed finished grade offset
  • Existing and proposed slope grade
  • Geogrid reinforcement length, details and backfill requirements
  • Temporary special shoring if needed
  • Limits of excavation and benching for the placement of backfill
Designate all information necessary for the contractor to construct RSS. This type of system does not have a proprietary vendor to provide shop drawings, so the plan set must be complete with details.