December 6, 2018

Best Practices for Zero Retaining Wall Failures - Slope Above Seismically Loaded Walls


Slopes above a wall are especially important to consider when dealing with a seismic loading applied to the wall.  The same acceleration coefficient applied to the wall must also be applied to the stability calculations of the slope.

In this scenario it is recommended that the slope above be minimized by regrading or increasing the height of the wall.

Additional geogrid layers are often used in the slope as well to add stability. (ref. BP, Chapter 11.2)

Allan Block is working to achieve our industry initiative of Zero Wall Failures. With our Best Practices Manual and experience in the industry we are trying to expand the knowledge base for the design of segmental retaining walls (SRW's) by communicating and educating the professionals in the industry.  To see the full Best Practices Manual, visit allanblock.com to download today and keep an eye out for more industry Best Practice recommendations here.

December 4, 2018

Best Practices for Zero Retaining Wall Failures - Recommendations Associated with Seismic Loading


If you are in an area where seismicity is a concern, then you should understand the local seismic code requirements, as this will likely play a role in the wall design.

In seismic applications closer spacing of geogrid is recommended, maximum 16 in (40 cm).  The top layer(s) of geogrid should also be extended, typically to roughly 90% or more of the wall height to satisfy design requirements.  Using select/structural backfill will also reduce the effects of the dynamic loading.


Allan Block is working to achieve our industry initiative of Zero Wall Failures. With our Best Practices Manual and experience in the industry we are trying to expand the knowledge base for the design of segmental retaining walls (SRW's) by communicating and educating the professionals in the industry.  To see the full Best Practices Manual, visit allanblock.com to download today and keep an eye out for more industry Best Practice recommendations here.

November 30, 2018

Best Practices for Zero Retaining Wall Failures - Wall Embedment with Toe Slope


Whenever walls are constructed in a terraced arrangement the designer should consider the overall global stability of the structure.

It is common to have the design grid lengths for the bottom terrace equal to at least 60% of the total terraced structure height.

Subsequent terraces above would use similar rationale to determine their minimum grid lengths.

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.  If the soils are not properly compacted in these areas, settlement can occur over time that could cause aesthetic concerns.  (ref. BP, Chapter 10.1)

Allan Block is working to achieve our industry initiative of Zero Wall Failures. With our Best Practices Manual and experience in the industry we are trying to expand the knowledge base for the design of segmental retaining walls (SRW's) by communicating and educating the professionals in the industry.  To see the full Best Practices Manual, visit allanblock.com to download today and keep an eye out for more industry Best Practice recommendations here.