Design of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes
Available Resources

New FHWA Mechanically Stabilized Earth Retaining Wall (MSE Wall) Manual

Design of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes The much anticipated LRFD update to the MSE Wall and Reinforced Soil Slope Manual is now available for download from the FHWA’s website. The full title of the document is Design of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes and it was authored by Ryan R. Berg, P.E.; Barry R. Christopher, Ph.D., P.E. and Naresh C. Samtani, Ph.D., P.E. Find the abstract and download link below. As time permits, I’ll try to post more about some of the changes in this important geotechnical publication.


Cover of FHWA NHI Mechanically Stabilized Earth Walls and Reinforced Slopes Design and Construction Guidelines course manual.
Available Resources

FHWA NHI 2009 MSE Wall Manual

Cover of FHWA NHI Mechanically Stabilized Earth Walls and Reinforced Slopes Design and Construction Guidelines course manual.[Disclosure] NCS Consultants is the employer (day job) of Randy Post, the owner of this site. [/Disclosure]

Geotechnical engineers who encounter MSE retaining walls or Mechanically Stabilzed Earth Walls are undoubtedly familiar with the FHWA NHI manual on “Mechanically Stabilized Earth Walls and Reinforced Soil Slopes”. This manual, along with the NCMA manual that is used for non-transportation projects, is virtually the bible for MSE wall design. In late summer/early fall of 2009, a revised version of this manual will hit the streets. Read on for more details.


Geologic Hazards

NY Landslide Halts Highway Construction

A report has been released by the NYSDOT on the Scoby Hill Landslide which has impacted a 4.2-mi improvement project of Route 219. The report, dated May 20, 2008 was headed to an FHWA peer  review panel.

The Feds were call in to help because of the unusual nature of the landslide. The slip surface is very deep, approximately 30-m (100-ft) below the surface and below all of the design phase investigations. And the remolded shear strength of the silty clay forming the slip surface was only 12-14 degrees.

Read on for more details of the slide. (Photo by NYSDOT)


Comings and Goings

FHWA’s Jerry DiMaggio to Retire

On Tuesday July 8, Jerry DiMaggio, P.E. was confirmed as the Implementation Manager for the Strategic Highway Research Program (SHRP2) at the National Academies. He will be retiring from the U.S. Department of Transportation, Federal Highway Administration (FHWA) Office of Bridge Technology, where he is the Principal Bridge Engineer – Geotechnical and National Program Manager (essentially the top dog geotechnical engineer in the country for surface transportation). He is an internationally recognized figure in geotechnical engineering and geo-construction. Read on for more details.


Standards and Codes

Changes in Geotechnical Engineering Practice in Arizona

[Editor] Note: NCS Consultants, LLC is Randy Post’s full time employer…ie. my day job! [/Editor]

There are some significant changes being made to the state of the practice in geotechnical engineering in Arizona. NCS Consultants, LLC has prepared three policy memoranda for the Arizona Department of Transportation or ADOT that have been issued to consultants all over the State. These memos are on the topics of bearing capacity and settlement of spread footings and retaining walls, the design of drilled shaft foundations in gravelly soils, and the preparation of drilled shaft axial capacity charts for use by bridge engineers.

Although primarily applicable to upcoming ADOT projects implementing the AASHTO 2007 LRFD code, the memos will have a ripple effect down through other local agencies within the state who frequently defer to ADOT guidelines for geotechnical engineering. Also, the memos and the ADOT/NCS approach to LRFD implementation in geotechnical engineering were presented by NCS at the 2008 TRB Conference in Washington D.C., and many other state DOTs and the FHWA were very excited about the memos. The approach used if not the exact content may become a model for other agencies. More info and links to download the policy memoranda are provided after the break.


Press Releases

ADSC Joins with FHWA to Conduct Hollow Core Soil Nail Research

The ADSC [Editor] (Association of Drilled Shaft Contractors) [/Editor] will join the FHWA as co-sponsors of a research project to develop a database of the available grout-to-ground bond stress of Hollow Core Anchors (HCAs) and to determine if correlations exist with traditional solid bar, drill and grout soil nails. The FHWA and the ADSC are interested in documenting the performance of HCAs in soil nail wall type construction and identifying methods of quality assurance so that HCAs can be specified with confidence in appropriate applications, both temporary and permanent. [Editor] Photo of hollow core nail installation underneath an existing bridge abutment, courtesy of NCS Consultants, LLC. Read on for the rest of the release. [/Editor]


Figure 1 This cut slope in massive, unfractuired conglomerate was smooth blasted. Treatment consisted of only drill trace removal on the main slope, but ledges were cut in natural boulder lenses at the cut end where similar features are in the adjoining natural terrain.

FHWA State Geotechnical Workshops

The FHWA has recently updated its geotechnical engineering site related to their annual State Geotechnical Workshops. All regions with the exception of the Southwest have their Workships this September and October. The next Southwest Geotechnical Engineers Conference will be in April of 2008. The 2007 SGEC was on April 23 – 27, 2007 in Overland Park, Kansas. They have posted PDF versions of the presentations at the conference on their FTP site. Read on for the dates of the upcoming workshops, as well as a link to the FHWA site and the presentation downloads.