Completed side-hill retaining wall for the SR 264 Second Mesa project in Arizona. Photo by Bharat Khandel, ADOT by way of NCS Consultants, LLC

Side Hill Retaining Walls – Part 2

Completed side-hill retaining wall for the SR 264 Second Mesa project in Arizona. Photo by Bharat Khandel, ADOT by way of NCS Consultants, LLCIn this part 2 of 2, various types of retaining walls are examined as possible alternatives in a side-hill retaining wall situation. These include conventional wall types such as CIP walls, MSE walls, gravity walls and soldier pile walls and some less conventional approaches such as lighweight concrete fill, hybrid soil-nail and geofoam wall systems, ground improvement and micropile walls.

Part 1 of this Side Hill Retaining Wall article covered the definition, significance, problems and failure modes, investigation techniques, analysis, and construction considerations of side hill walls. A PDF version is now available for download as well. Click through for the article and the download link!


Available Resources

Video: RPI Geotechnical Engineering Centrifuge

I stumbled across this video for the geotechnical engineering centrifuge at Rensselaer Polytechnic Institute. Centrifuge testing is a popular way to economically test models at much higher loads and pressures than you would normally be able to in the laboratory. The goal is to more accurately represent the real world conditions. Click through for the video.


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.


Available Resources

Technological Advances in Geotechnical Engineering

According to James Miller of GeoEngineers, Inc., the most significant recent technological advances in geotechnical engineering are LiDAR, GIS-based data management, and advanced analysis of soil-structure interaction. Read his article at Thanks to iCivilEngineer […]

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.


No Picture
Journal Article Reviews

Drilled Shaft Industry Notes

In the May 2007 edition of Foundation Drilling Magazine, a publication of the Association of Drilled Shaft Contractors (ADSC), Silas Nichols, PE of the Federal Highway Administraton provided a summary of the FHWA’s role in providing guidance on drilled shaft design and construction over the years through research funding, publications and involvement in AASHTO and other agencies. Also in the article is an overview of upcoming updates to AASHTO codes, and FHWA publications. Read on for more details.


Project Related

Jefferson Memorial’s Signs of Sinking Raise Fresh Alarms

The National Park Service is carefully monitoring a settlement problem at the Jefferson Memorial in Washington D.C. The geotechnical problem area is a seawall that borders the Memorial’s plaza that seems to be settling away from the plaza. Read on for more info. [Photo by esev]


Available Resources

New Publications from Transportation Research Board

Two new publications have been released from the Transportation Research Board. Pavement Management; Monitoring, Evaluation, and Data Storage; and Accelerated Testing 2006 and Geotechnical Challenges of the Interstate Highway System: The First 50 Years and […]