GSI to host webinar on failed MSE walls

The Geosynthetic Institute (GSI) will sponsor a webinar, “A database and analysis of 320 failed MSE walls with geosynthetic reinforcement,” on September 9, from 11:30 a.m. to 1 p.m. EDT. Geosynthetic Materials Association (GMA) member companies and their employees receive discounted rates on all GSI webinar and short course registrations.

Mechanically stabilized earth walls, berms and slopes with geosynthetic reinforcement have been developed since the 1970s; first with geotextiles and then with geogrids. Our estimate is that approximately 200,000 exist and the technology is utilized worldwide. Unfortunately, there have been many failures; some with excessive distortion while others have collapsed in whole or part. The main statistical findings of the 320 case histories that we have on file are as follows:

1. 98% were private walls
2. 70% failed between 1999–2010
3. 79% were in North America
4. 75% were masonry block faced (i.e., SRWs)
5. 83% were 13.1 to 39.4 feet (4 to 12 m) high
6. 94% were geogrid reinforced (others, geotextiles)
7. 75% failed in less than four years
8. 73% used silt and clay backfill soils
9. 76% had poor or moderate compaction
10. 99% were caused by improper design or construction; none (0%) were geogrid or geotextile manufacturing failures
11. 63% caused by internal or external water (i.e., remaining 37% caused by soil-related issues)

Details of this data set will be described, and four salient features will be discussed in detail:

1. fine-grained soil backfills
2. compaction of these same soils
3. routing of internal drainage systems
4. surface and adjacent water control

Concluding comments will include specific recommendations for designers and contractors alike.

Participants will become familiar with details of geosynthetic-reinforced MSE structures. Different modes of failure (deformation versus collapse) will be illustrated. These 320 failures will be categorized insofar as soil-related versus water-related along with the primary accompanying details. This webinar will hopefully lead to mitigating the large number of current failures in the future.

Webinar benefits:

1. Understand the idiosyncrasies of MSE structures
2. Learn about the major circumstances of failures
3. Learn the significance of soil issues vis-à-vis water issues
4. Learn of the various weaknesses of soil issues and water issues insofar as failures are concerned
5. Learn about four specific issues which are involved in most of the failures
6. Understand the negative implications that this large group of failures has on the credibility of the technology and on everyone involved in it

This webinar will benefit owners of MSE walls, berms and slopes in both the public and private sectors; federal, state and regional geotechnical, transportation, and environmental engineers; engineers from municipal districts and townships; private and municipal land developers; architectural and landscape designers; general civil consulting engineers; testing laboratories servicing these organizations; manufacturers and representatives of geosynthetic materials; contractors and installers of MSE walls, berms and steep soil slopes; academic and research groups; and others desiring technically related information on this important aspect of our constructed infrastructure.

About the presenter

Dr. George R. Koerner is the director of the Geosynthetic Institute, a position that he has held since 2014. Koerner’s interest in geosynthetics spans his entire professional life from undergraduate work in the 1980s to the present. He holds his Ph.D. in civil, architectural and environmental engineering from Drexel University in Philadelphia, Pa. Koerner’s master thesis was on direct shear testing of geosynthetic interfaces and his doctoral dissertation was on landfill leachate clogging of soil and geosynthetic filters. Both are regularly cited to this day.

Koerner is a professional engineer in both Pennsylvania and New Jersey and is an ASQC quality auditor.

***

Webinars cost $200.00 for GSI and GMA members, and $250.00 for nonmembers. Successful completion of a multiple-choice test after the webinar carries 1.5 professional development hours (PDH).

For more information or to register, visit http://www.geosynthetic-institute.org/webinar.htm.