MSE SEGMENTAL BLOCKRETAINING WALL NOTES
The followingMSE Segmental Block 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 To avoid the use of outdated notes, always get new notes for every project.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, 2017 Edition.
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
- The Mechanically Stabilized Earth (MSE)Segmental Block Retaining Wall shall be on the current approved products list located at the following website address:
Use note number 2 when the wall blocks are required to have a specified texture and/or color.
- The segmental blocks shall be a commercially available block intended to simulate a natural rock wall. Blocks shall be colored to blend with the surrounding landscape. Color may be achieved by the use of colored concrete or surface staining. A minimum of 3 colors shall be used to prevent a uniform appearance. Submit block pattern, colors, and method of achieving colors to the Engineer for approval a minimum of 2 weeks prior to fabrication.
- The Contractor shall consult with an approved MSE wall manufacturer to obtain design calculations and construction plans. Two copies of this data shall be forwarded to the Bridge construction Engineer a minimum of 2 weeks in advance of construction for approval. Construction plans shall include plan view, elevation view (to include elevations), typical cross sections, foundation and drainage details, material and construction specifications, and a detailed listing of all quantities required for MSE wall construction including segmental blocks, excavation, soil reinforcement and granular backfill.
- Backfill for the MSE wall shall be granular material conforming to the following specifications:
Sieve SizePercent Passing
1 Inch 100
¾ Inch 75-100
No. 4 40-70
No. 40 10-60
No. 200 0-5
Plasticity Index: Less than or equal to 6.
- A granular leveling pad is required for the MSE segmental block retaining wall system. The minimum embedment depth to the top of the leveling pad shall be 2 foot or as recommended by the Foundations Engineering Activity. The leveling pad shall be constructed using granular material conforming to the specifications for Aggregate Base Course in Section 882 of the Specifications, unless otherwise specified by the MSE wall supplier.
- The retaining wall shall be installed in accordance to the selected wall companies’ instructions, specifications, and approved shop drawings.
UNDERDRAIN
If an underdrain is recommended by the Geotechnical Engineering Activity, use the following notes.
- 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.
- The polyethylene tubing shall conform to Section 990 of the Specifications.
- 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
After the required excavation has been completed to the leveling pad elevation, the foundation material (including the area of the proposed wall backfill) shall be compacted using a vibratory roller to provide a uniform compacted foundation for the wall system. Any voids encountered shall be filled and brought up to grade with compacted granular material conforming to the specifications for Aggregate Base Course in Section 882 of the Specifications.
Additional 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.