Segmental Retaining Walls - just design per best practices?

[Ben29]

I was asked to design a segmental retaining wall for a homeowner. I have never designed a segmental retaining wall before. The wall is going to retain about 8ft-9ft of soil. Can I just design the wall per the "best practices" or is there more to it? Do I need to get a geotech involved and purchase a SRW design program for this?

https://www.allanblock.com/literature/PDF/best-practices-for-SRW-walls.pdf

 

[dik]

I've used Allan block, it's a good product and there are several two or three suppliers of segmental precast walls. Some even have their own software. It can be quite attractive. Best to contact the suppliers and see how they can help you. I think it was Allan block that provided the first software (about 20 years back for a 20' high wall) and I think I've also used Redi-rock software.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[SJBombero]

Allan block has their own software for free. You just have to go through a short online training class with them. It is fairly comprehensive and will generate all the CAD details for you down to the correct elevations.

 

[geotechguy1]

There is a program called VESPA (

https://www.ctiware.com/vespa)

which you can use to design a large number of different types of segmental block walls and is preloaded with a wide array of block types and geogrid types. Depending on the configuration, for relatively short wall heights like 8 - 9 feet, the block manufacturers often produce tables with standard designs / geogrid lengths for certain soil conditions.

Regarding whether or not you can design it, I'm somewhat ambivalent about it. I think, at a minimum, you need a geotechnical engineer to tell you what parameters you can use for the various soils. Practically speaking it may be best to find a geotech to design it or talk to the block manufacturers. To be honest with you most block manufacturers will essentially design the wall for you, and let you take the risk by stamping the design, or alternatively, they all have relationships with geotech engineers who can do the design at a low price. It might only cost 2-3k to have a geotech design it, and that amount again for inspection and testing costs.

 

[SJBombero]

My experience has also been that there is little value added by having a structural engineer design these. As long as a geotech provides the soil parameters.

 

[JoelTXCive]

We have had segmental blocks on several projects. It was my understanding that specific block geometry and layouts were often proprietary to the manufacturers.

Our process is just to get some basic geometry from Allan Block; and then have the contractor submit signed & sealed sheets based on the projects' geotech report.

I have always assumed the block wall people have their own favorite engineers that do these designs everyday. They are much more efficient with their designs and design time.