FHWA | Dan Brown and Associates, PLLC

New FHWA Drilled Shaft Manual is Done!

By Robert Thompson, on July 7th, 2010

Although I have known for several weeks that the manual was finished (I work for one of the authors, after all!), I was waiting for the FHWA to post the link for the new manual before posting this…and now it is here! My friend, Randy Post, has an outside review (meaning not connected to one of the authors!) over at his blog Geoprac.net. Not only did he get “the scoop” on me, but he covers some of the highlights of the “what’s new” with the new, fully revised manual. The biggest change is completely re-writing the design sections to follow LRFD as well as to update the methods for calculating soil and rock resistance. As Randy also notes, the manual has been given a Geotechnical Engineering Circular (GEC) designation: GEC 10. Make sure and go read his review, as well as check out the other things on his blog (disclosure by Robert: I am an occasional contributor there).

The manual’s authors are three of the country’s top experts in drilled shaft design and construction: our own Dan A. Brown, Ph.D, P.E. , John P. Turner, Ph.D, P.E. of the University of Wyoming, and Raymond J. Castelli, P.E. of Parsons Brinckerhoff. As with any major FHWA publication such as this, there was significant industry involvement in the review process through various technical committees and individuals from ADSC, DFI, and Geo-Institute. A note from Dan:

The completion of this manual is a great relief and satisfaction. Many thanks to John Turner’s hard work and also for Ray Castelli’s diligent work to review and make us better. Special thanks to PB Project Manager Jeremy Hung and our FHWA sponsor Silas Nichols for their dedicated efforts to help get this done, and to all of you who contributed.

Dan and John have been using the material in the NHI course this fiscal year, having done some pilot courses the previous year. Some NHI courses, including the Drilled Shaft course, can be hosted by non-government groups. There are also some public seats available occasionally at DOT hosted courses. The NHI catalog page for this course is here.

Download Drilled Shafts:Construction Procedures and LRFD Design Methods, 2010.

Also linked on our Publications page.

Update (7/12/10): For those that prefer the feel of a printed volume in their hands, the ADSC: The International Association of Foundation Drilling will be the distributor of the printed volume of the manual through their Technical Library. It will be available soon, according to ADSC. We’ll post about it as soon as it is available.

Update 2 (8/19/10): The printed manual is now available.

Foothills Parkway Bridge No. 2 – Smokey Mountains, Tennessee

By Robert Thompson, on February 11th, 2010

DBA is the geotechnical engineer for a pre-cast post-tensioned segmental concrete bridge that is part of what is called the “missing link” in the Foothills Parkway (see background information below) near the Great Smokey Mountains National Park. The National Park Service has awarded a design/build contract to Bell & Associates Highway Construction of Brentwood, TN. VSL will cast and erect the post-tensioned segmental bridge. The lead bridge designer is Corven Engineering, Inc. of Tallahassee, FL. Palmer Engineering in Nashville, TN will be the structural/civil engineer for the project. Some design work was begun by FHWA Eastern Federal Lands Division in the 1990’s but was never completed and let for bid due to lack of funding. The process to complete the “missing link” has begun again using the design/build delivery system.

Since the purpose of the Parkway is to provide scenic views of the mountains and valleys, the project has strict requirements to minimize disturbance. In addition to special design and construction techniques (to be discussed in a later post after design is complete), Bell included significant attention to landscaping and site preservation. Hedstrom Design of Knoxville, TN is the landscape architect for the project, providing services key to minimizing impact on the site from construction activities, as well as providing a finished look to the the project that blends with the surrounding landscape.

Design work is well under way and Bell has started work at the site. The bridge is scheduled to be completed by November, 2011 – a very tight schedule!

A local news article about the project award is here in the Cherokee One Feather.

Click on the image to see a map of the Parkway (Source: Briefing Statement linked below):

Background information on the Parkway and the “Missing Link”:

Congress authorized the Foothills Parkway as a scenic parkway on February 22, 1944 (Public Law 232). The stated purpose of the Parkway is to provide beautiful vistas of the Great Smoky Mountains along their northern flank (TN) and to disperse traffic in the area. The entire 72-mile corridor is administered by Great Smoky Mountains National Park. To date, two discontinuous segments totaling 22.5 miles are completed and open. The Parkway parallels the Park’s northern boundary from Chilhowee Lake, TN (Section 8H) to I-40 near Cosby, TN (Section 8A).

Between 1966 and 1970, a 6.4-mile section of road between U.S. Highway 321 in Walland and Carr Creek (Section 8F), was constructed. In the 1980s, two contracts were awarded for construction of approximately 10 miles of road (Section 8E). Both projects experienced structural fill failures and erosion problems that caused the projects to be suspended in 1989, thus leaving a 1.65-mile segment uncompleted around Caylor Gap which is referred to as the “missing link.” In the 1990s, a new design was developed by the Federal Highway Administration (FHWA) to complete the “missing link” using bridges, walls, and fills to minimize surface disturbance and environmental impacts.

Source: Briefing Statement, Great Smokey Mountains National Park, Completion of the Foothills Parkway, May 2009