MSE WIRE FACE RETAINING WALL NOTES

The following MSE Wire Face Retaining Wall notes are furnished to assist in providing consistency in plan notes between projects. To avoid the use of outdated notes, always get new notes for every project. Required or requested changes should be submitted to the Office of Bridge Design for inclusion into the standard notes.

The notes shown are intended to be base notes. These notes are not intended to cover all circumstances and may need to be modified to reflect specific conditions at each individual wall site.

Care should be taken not to modify standard notes once they are included in structure plans.

The file format is as follows:

Comments regarding note use are highlighted in yellow. These comments are intended to help clarify when particular notes should be used and, if necessary, to provide guidance when using specific notes.

Information within various notes that is project specific and needs to be changed/updated etc. for a particular project will be in orange font. The information shown in orange may need to be changed, deleted or added to for applicability to specific structures. Before plans are distributed for review, change all text to a black colored font.

It will be necessary to delete both unnecessary notes and all comments when creating plan notes.

SPECIFICATIONS

1. Design Specifications: AASHTO LRFD Bridge Design Specifications, 2014 Edition with 2015 and 2016 Interims.

2. Construction Specifications: South Dakota Standard Specifications for Roads and Bridges, 2015 Edition and Required Provisions, Supplemental Specifications, and Special Provisions as included in the Proposal.

RETAINING WALL

  1. The Mechanically Stabilized Earth (MSE)Wire Face Retaining Wall shall be on the current approved products list located at the following website address:
  1. See Special Provision for Permanent Mechanically Stabilized Earth Wire Faced Walls.
  1. The minimum embedment depth to the bottom of the MSE Wire Face retaining wall shall be 2.0 ft.
  1. Horizontal dimensions shown are measured along the front face of the wall at the bottom of wall elevation.
  1. Top of wall elevations shown are minimum wall limits.
  1. The retaining wall shall be installed in accordance to the selected wall companies’ instructions, specifications, and approved shop drawings.

Use notes7 and 8 if steel piling are located within the reinforced backfill.

  1. A 24-inch (minimum inside diameter) steel casing shall be installed at abutment pile locations prior to the placing and compacting of fill for construction of the proprietary wall(s). Fifteen (15) casings are required. See bridge plans for pile and casing locations. The Contractor’s method of installing casing shall be submitted to the Engineer for approval a minimum of 2 weeks prior to construction Casing shall be cut off 3” below the bottom of the abutment footing. The type of casing proposed by the Contractor shall be of sufficient strength to withstand all forces including those from earth pressure and shall be approved by the Engineer. The cost of furnishing and installing the casings shall be incidental to the contract unit price per cubic yard for “Granular Backfill for MSE Wire Face Wall.”
  1. The Contractor shall take necessary precautions to prevent displacement of the casings during placing and compacting fill material within close proximity of the casings. Granular backfill material within three feet of the casings shall be placed in lifts and compacted as directed by the Engineer to obtain required density.
  1. If the designer of the MSE Wire Face wall determines that “sliding” controls the reinforcement length during the design of the wall, the designer shall consult the Department’s Geotechnical Engineering Activity for possible alternatives that may be more economical than lengthening the reinforcement.
  1. A layer of Type B Drainage Fabric shall be placed over the top of the Granular Backfill for MSE Wire Face Wall prior to placing any soil over the granular backfill. The intent of the fabric is to act as a separator and keep fines from intruding into the granular material. All costs in furnishing and installing the Type B Drainage Fabric shall be incidental to the contract unit price per cubic yard for “Granular Backfill for MSE Wire Face Wall.”

UNDERDRAIN

If an underdrain is recommended by the Geotechnical Engineering Activity, use the following notes.

  1. An underdrain system shall be installed behind the wall as shown and detailed on the General Drawing. The underdrain system shall consist of 4” diameter slotted corrugated polyethylene tubing installed behind the wall and 4 inch diameter corrugated polyethylene tubing from the end of the wall to the outlet as shown. Care shall be taken near the ends of the wall to ensure positive drainage.
  1. The polyethylene tubing shall conform to Section 990 of the Specifications.
  1. All costs involved in furnishing and installing the 4 inch diameter slotted corrugated polyethylene tubing and 4 inch corrugated polyethylene tubing shall be included in the contract unit price per foot for “4 Inch Diameter Underdrain Pipe.”

FOUNDATION PREPARATION

Foundation Preparation notes, if required, will be provided by the Geotechnical Engineering Activity. This work may need to be coordinated with the grading work covered in the grading portion of the plans and care must be taken to ensure that any notes provided are placed in the plans accordingly.