Best Practices for Segmental Retaining Walls Best Practices

Disclaimer


The intent of this material is to communicate the best practices for design of Segmental Retaining Walls (SRW) as determined by Allan Block Corporation based on 25 plus years of research, design and field experience. This is not meant to be a final authority as each project has its own set of unique situations.

The local engineer of record must use their best engineering judgment to account for those situations that present themselves and provide a safe and efficient design for the customer. At no time does the contractor or local building official have the authority to override the approved plans and specifications provided from the local engineer of record.

It is the recommendation of Allan Block Corporation that the local engineer of record work for and be paid by the project owner. It has been determined that the local engineer of record should be the Project Site Civil Engineer as they are best suited to take responsibility for the design, and how it affects the site, whether they do the design in-house or use an outside consultant to do the design for the project.

The Project Site Civil Engineer has control of several of the overall aspects of the project and therefore is most able to properly handle the integration and communication required to ensure the performance of the wall complies with the needs of the site. For wall design applications that are outside of the experience level of the Project Site Civil Engineer, a wall designer with the appropriate knowledge and experience should be contracted with by the Project Site Civil Engineer. It is recommended that the wall contractor not be responsible for securing the engineering.

last updated: 1/14/2022

Chapter 5: Water Applications

typical water management

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Click on the topics below to view more information on the best practices for Allan Block segmental retaining wall design for residental and commercial applications.

Design Guidelines Item: The term, "owner" refers to the property owner or their designated representative.

5.1    Below Grade Water Management

5.1   Below grade water management plan for water application walls.

  1. When more than incidental groundwater is known to move through the retained soils.
    1. The wall rock should be placed to the limits of the geogrid lengths up to a height equal to 30 cm higher than any water source.

5.2   Water Appplication Construction

5.2    When a wall is constructed to be a water application such as in a lake, stream or detention basin.


Mechanical Property Determination Method
Tensile Strength = 39.4 kN/m ASTM D-4595
Puncture Strength = 4228 N ASTM D-6241
Apparent Opening Size (AOS)
= U.S. Sieve #70 0.212 mm		 ASTM D-4751
Trapezoidal Tear = 445 N ASTM D-4533
Percent Open Area = 4% COE-02215
Permeability = 0.01 cm/sec ASTM D-4491
Table 2: Embankment Protection Fabric Specifications
  1. The wall rock should be placed to the limits of the geogrid lengths up to a height equal to 30 cm higher than the determined high water mark. If the high water mark is unknown, the entire infill zone should be constructed with wall rock.
  2. The drain pipe should be raised to the low water elevation to aid in the evacuation of water from the reinforced mass as water level fluctuates.
  3. Embankment protection fabric should be used under the infill mass and up the back of the infill mass to a height of 30 cm higher than the determined high water mark.
    1. Embankment protection fabric is used to stabilize rip rap and foundation soils in water applications and to separate infill materials from the retained soils. This fabric should permit the passage of fines to preclude clogging of the material. Embankment protection fabric shall be a high strength polypropylene monofilament material designed to meet or exceed typical NTPEP specifications; stabilized against ultraviolet (UV) degradation and typically meets or exceeds the values in Table 2.
  4. For walls having moving water or wave action, natural or manufactured rip-rap in front of the wall to protect the toe of the wall from scour effects is recommended.