Installation Guidelines - NCMA

							Recommended Installation Guidelines
Recommended Installation Guidelines

NCMA
Segmental Retaining
Wall Installation
Guide (2010)
Recommended Installation Guidelines
Construction Planning
Excavation
Preparing the Leveling Pad
Place Drainage Pipe
Installing Base Course
Installing Facing Units
Installing Gravel Fill
Place Infill Soil
Compaction
Installing Geosynthetic Reinforcement
Capping and Grading
Recommended Installation Guidelines
Recommended Installation Guidelines
 Granular
 Compacted to 95%
   (ASTM D-698)
 Minimum size:
   6” Thick
   6” Wider than
    base each way
   Cover drain
Recommended Installation Guidelines
 Recommended Installation Guidelines
Important to address subsurface water
PVC, ABS or corrugated pipe
  4” minimum
  Correct side up
  Geotextile wrap
  Slope to drain
  Daylight drain
  Tie into stormwater
Recommended Installation Guidelines
Most important course in the wall
Determines trueness of the finished wall
Uniform bearing on leveling pad is essential
Recommended Installation Guidelines
Must be level in both directions
Use string line and level for alignment
Use string line to achieve smooth radii
  Use on molded face only (not split face)
Recommended Installation Guidelines
Recommended Installation Guidelines
 Fill voids with gravel fill
 Compact with hand-operated plate vibrator (250 lb. minimum)
 3 feet from back of wall
 95% ASTM D-698
Recommended Installation Guidelines
Recommended Installation Guidelines
 Tolerance for completed wall
   +/- 1.25” over 10’ distance
   Both vertical and horizontal
Recommended Installation Guidelines
Recommended Installation Guidelines
• Place & compact infill soil behind aggregate
• Compact carefully
• 95% ASTM D-698
Recommended Installation Guidelines
Recommended Installation Guidelines
 Ensure aggregate & infill soil are level
 Cut to length plus facing unit depth
 Clean debris off top of unit
 DO NOT OVERLAP!!!
Recommended Installation Guidelines
Recommended Installation Guidelines
 6” of backfill before
  using vehicles
 No turning of
  vehicles
 No sudden breaking
  or sharp turns
 Keep heavy
  equipment no closer
  than 3’ of wall
Recommended Installation Guidelines
Recommended Installation Guidelines
 Concave corners and radii
Recommended Installation Guidelines
 Convex corners and radii:
 3” of Soil between overlap
 Optionally, skip courses
Recommended Installation Guidelines
Install cap blocks
 with adhesive
Ensure drainage
 away from SRW
 system
Grade drainage
 swale
Minimum 8” low
 permeable soil
Vegetate slopes
Recommended Installation Guidelines
Detailing