• NCDOT Geotech Alerts

    NCDOT Geotech Alerts for revisions and additions to standards are sent via an email distribution list.  Please provide your name and email to be added to the Geotechnical Distribution List.

     

  
  
  
  
  
  
Summary of Changes
Anchored and Soil Nail Retaining Wall CellsRevised12/17/2019Cell
  • ​Adds seismic note to Anchored Wall and Soil Nail Wall Cells with standard notes
Anchored and Soil Nail Retaining Wall NotesRevised12/17/2019Notes
  • ​Adds seismic note for consistency with changes to Anchored Wall and Soil Nail Wall Provisions for seismic criteria
3,5,6Anchored, Soldier Pile and Soil Nail Retaining WallsRevised12/17/2019Provision
  • Updates Anchored and Soil Nail Wall Provisions for 2018 Standard Specifications
  • Updates Soildier Pile Wall Provision for consistency with Anchored Wall and Soil Nail Wall Provisions
  • Revises seismic criteria for anchored and soil nail walls to meet AASHTO and Structure Management Unit requirements
  • Changes grout requirements for ground achors and soil nails to be consistent with Structure Bulletin and AASHTO soil nail wall ballot items
  • Incorporates LRFD design for soil nail walls through AASHTO soil nail wall ballot items
  • Incorporates Slide and new Snail software programs for soil nail wall analysis and design verification
  • Incorporates AASHTO Bridge Construction Specs for soil nail wall materials, corrosion protection and nail testing through AASHTO soil nail wall ballot items
  • Clarifies traffic impact requirements for soil nail wall design
Geotechnical Summary TablesRevised12/17/2019Form
  • ​​Adds new table for horizontal drains
SP08 R017Horizontal DrainsNew12/17/2019Provision
  • ​Creates new provision for horizontal drains with or without drain pipes to drain water from slopes and rock cuts and from behind retaining walls
8Reinforced Soil SlopesRevised12/17/2019Provision
  • ​Revises provision for new Geosynthetic Reinforcement Evaluation Program (formerly called Geogrid Evaluation Program)
  • Updates link for list of approved geosynthetic reinf. (list was moved from the M&T website to the Geotech website) for primary geogrids
  • Adds requirement for American made biaxial geogrids for secondary geogrids
  • Increases minimum width/length of secondary/primary geogrids to 6'
  • Removes option for splicing primary geogrids
817.01Standard Horizontal DrainNew12/17/2019Detail
  • ​Creates new standard detail for horizontal drains with or without drain pipes to drain water from slopes and rock cuts and from behind retaining walls
1802.01,02Standard Reinforced Soil Slope with High Groundwater, Standard Reinforced Soil Slope with Low GroundwaterRevised12/17/2019Detail
  • ​Revises detail for new Geosynthetic Reinforcement Evaluation Program (formerly called Geogrid Evaluation Program)
  • Updates link for list of approved geosynthetic reinf. (list was moved from the M&T website to the Geotech website) for primary geogrids
  • Adds flood elevation to notes on High GW RSS detail
  • Increases minimum width/length of secondary/primary geogrids to 6'
  • Removes option for splicing primary geogrids
SP05 R008Aggregate SubgradeNew5/15/2018Provision
  • ​Designates current aggregate subgrade in Section 505 as a Type 1 Aggregate Subgrade and adds a Type 2 Aggregate Subgrade
  • Includes thickness, proofrolling, compaction and undercutting requirements for each aggregate subgrade type
SP05 R017Class IV Subgrade Stabilization in Lieu of Chemical StabilizationRevised5/15/2018Provision
  • ​Adds proofrolling requirement and aggregate subgrade type for Class IV Subgrade Stabilization
Geotechnical Summary TablesRevised5/15/2018Form
  • ​Revises Summary of Aggregate Subgrade/Stabilization table to accommodate both aggregate subgrade types
7Geotextile for Pavement StabilizationRevised5/15/2018Provision
  • ​Adds proofrolling requirement and aggregate subgrade type for Class IV Subgrade Stabilization
SP04 R002BAlternate Bridge Approach Fills for Integral AbutmentsNew1/16/2018Provision
  • ​Addresses new bridge approach fill for integral abutments (2018 Roadway Standard Drawing No. 422.03)
  • Includes Contractor's option for new Type A Alternate Approach Fill for Integral Abutments
SP04 R002ABridge Approach FillsRevised1/16/2018Provision
  • ​Addresses new bridge approach fills (2018 Roadway Standard Drawing No. 422.01 and 422.02 and Roadway Detail Drawing No. 422D10)
  • Includes 3 new bridge approach fill types (Type I Standard Approach Fill, Type II Modified Approach Fill and Type III Reinforced Approach Fill for MSE Abutments)
SP05 R017Class IV Subgrade Stabilization in Lieu of Chemical StabilizationRevised1/16/2018Provision
  • ​Adds substitution is not allowed for chemically stabilized sections with geotextile for pavement stabilization
  • Makes minor updates for 2018 Standard Specifications
16Compaction GroutingNew1/16/2018Provision
  • Addresses compaction grouting to stabilize subgrades and embankments and prevent future subsidence
  • Requires the use of a prequalified Subsurface Grouting Contractor
  • Pays for compaction grouting in cubic feet of grout pumped and linear feet of grout pipe installed
SP09 R005Foundations and Anchor Rod Assemblies for Metal PolesRevised1/16/2018Provision
  • ​Adds standard foundation for light standards
  • Makes minor updates for 2018 Standard Specifications
Geotechnical Design Cell LibraryNew1/16/2018Cell
  • Removes Standard Embankment Monitoring and Rock Plating Details because these details are Roadway Standard Drawings No. 235.01 and 275.01, respectively, in the 2018 Roadway Standard Drawings
  • Revises Standard CIP and Segmental Gravity Wall Detail Nos. and CIP, Segmental and Precast Gravity Wall Cells and Notes because these wall types are Sections 453, 454 and 455, respectively, in the 2018 Standard Specifications
  • Revises Notes for the Concrete Barrier Rail with Moment Slab Cell because barrier rails with moment slabs are incorporated into Section 460 in the 2018 Standard Specifications
  • Revises Soldier Pile Wall Cell and Note because Section 442 is rewritten in the 2018 Standard Specifications
  • Revises MSE Wall Notes and MSE Abutment Wall Cells because bridge approach fill details and provisions will be significantly changed for 2018 lettings
Geotechnical Summary TablesRevised1/16/2018Form
  • ​Revises footnote for Summary of Aggregate Subgrade/Stabilization table
  • Adds Class IV Subgrade Stabilization to Summary of Geotextile for Pavement Stabilization table
7Geotextile for Pavement StabilizationRevised1/16/2018Provision
  • ​Adds Class IV Subgrade Stabilization over Geotextile for Pavement Stabilization for pavement sections with asphalt base or surface course
  • Makes minor updates for 2018 Standard Specifications
4MSE Retaining Walls (LRFD)Revised1/16/2018Provision
  • ​Revises provision for new Type III Reinforced Approach Fill for MSE Abutments
  • Removes restriction for 57 stone with geosynthetic reinforcement since Geogrid Evaluation Program includes full scale damage testing from NTPEP Evaluations
  • Makes minor updates for 2018 Standard Specifications
8,9Reinforced Soil Slopes, Cellular Confinement SystemsRevised1/16/2018Provision
  • ​Makes minor updates for 2018 Standard Specifications and other Department changes
  • Revises material requirements for geocell tendons and crest anchorages
  • Expands and further defines design requirements for cellular confinement systems
SP14 R004Roadway Lighting FoundationsNew1/16/2018Provision
  • ​Combines 2012 Roadway Standard Provision "High Mount Foundations" with Section 1405 "Standard Foundation" that was removed from the 2018 Standard Specifications
  • Addresses High Mount Foundation (2018 Roadway Standard Drawing No. 1402.01) and Standard Foundation (2018 Roadway Standard Drawing No. 1405.01)
Standard Foundation Notes (LRFD)Revised1/1/2018Notes
  • ​Adds new note for MSE abutment walls
  • Updates notes for 2018 Standard Specifications
Summary of Quantities WorksheetRevised11/29/2017Form
  • ​Updates pay item information for 2018 Standard Specifications and Special Provisions
  • Adds Class IV Subgrade Stabilization for geotextile for pavement stabilization
3,9,10Anchored Retaining Walls (LRFD), Soil Nail Retaining Walls (LFD-ASD), Soldier Pile Retaining Walls (LRFD)Revised5/16/2017Provision
  • ​Revises materials for most recent Geosynthetics (Section 1056) Provision
  • Updates geocomposite drains for most recent Geosynthetics (Section 1056) Provision
Anchored, Soil Nail and Soldier Pile Wall TypicalsRevised5/16/2017Cell
  • ​Updates geocomposite drains for most recent Geosynthetics (Section 1056) Provision
Drilled Piers (LRFD)Revised5/16/2017Provision
  • ​ Replaces Table 411-3 from the Standard Specifications with specific polymer slurry requirements for each approved polymer
  • Adds exception to method of measurement for SPT testing
6MSE Retaining Walls (LRFD)Revised5/16/2017Provision
  • Clarifies and improves wording
  • Adds electrochemical testing requirements for coarse aggregate from coastal plain sources
  • Adds exceptions to FHWA requirements for rubber bearing pads
  • Adds minimum gauge thickness for steel strip reinforcement
  • Adds aluminized coating as an option for steel strip reinforcement
  • Removes geostrips
  • Replaces prequalification with other requirements for engineers designing MSE panel walls
  • Addresses gap between concrete barrier and MSE wall facing
  • Adds corrugated steel pipes for pile sleeves
  • Adds polypropylene geogrid reinforcement for MSE abutment walls with polyester type (PET) geogrid reinforcement connected to SRW units
  • Adds materials for PET geogrid reinforcement vertical obstruction detail
MSE Wall Typicals and DetailsNew5/16/2017Cell
  • ​Adds 2 new abutment wall cells with pile sleeves
  • Adds polypropylene geogrid reinforcement to abutment wall cells for MSE abutment walls with polyester type (PET) geogrid reinforcement connected to SRW units
  • Adds geogrid cap connection detail to MSE abutment wall with SRW units cells
  • Adds a new cell for PET geogrid obstruction details for MSE segmental walls and moves leveling pad detail for SRW units to this cell
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