Best Practices for Segmental Retaining Walls Best Practices


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: 8/11/2015

Chapter 10: Global Stability - Terraced

Global Stability Terraces

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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.

10.1   Wall Embedment with Toe Slope

Terraced Retaining Walls

Figure 10-1: Terraced Wall Applications

10.1   Whenever walls are constructed in a terraced arrangement, or any of the other conditions listed, the designer must consider the overall global stability of the structure.

  1. It is common to have the design grid lengths for the bottom terrace equal to at least 60% of the total terraced structure height.
  2. Subsequent terraces above would use similar rationale to determine their minimum grid lengths.
  3. When determining the surcharge applied from the upper wall onto the lower wall, it is common to consider the walls as independent if they are spaced apart a minimum of twice the height of the lower wall. If they are spaced closer, the lower wall must be designed to carry the surcharge of the upper wall(s), Figure 10-1.
  4. These recommendations do not eliminate the need to consider a global stability analysis.
  5. Greater attention to compaction should be placed on the foundation soils below the upper terraces and in transition areas where the wall splits from one wall into two.
    1. If the soils are not properly compacted in these areas, settlement can occur over time that could cause aesthetic concerns.