Now Published! NCHRP Synthesis 418–Developing Production Pile Driving Criteria From Test Pile Data

Tim Siegel (January 22, 2012): Innovative Techniques for Characterizing Karst Terrain, Workshop on Geo-innovation in Subsurface Exploration, TRB Annual Meeting, Washington, D.C.

John Turner and Robert Thompson (February 21-23, 2012): NHI Drilled Shaft Course - Kansas DOT, Topeka, Kansas

Robert Thompson (February 24, 2012): Conservatism in Drilled Shaft Design When Utilizing Rock Sockets, Alabama Transportation Conference, Montgomery, Alabama

Tim Siegel (March 15, 2012): Micropile Design Installation and Performance for the Foothills Parkway, ADSC Equipment EXPO and Technical Conference, San Antonio, Texas

Robert Thompson (March 15, 2012): Full-Scale Load Tests on Drilled Shafts in Tennessee and Georgia, ADSC Equipment EXPO and Technical Conference, San Antonio, Texas

Erik Loehr (March 15, 2012): Slope Stabilization Using Micropiles, ADSC Equipment EXPO and Technical Conference, San Antonio, Texas

John Turner (March 27, 2012): Foundations for the Bridge at Pitkins Curve - GeoCongress 2012 - ASCE/Geo-Institute - Oakland, California

TBA (April 10-12, 2012): NHI Drilled Shaft Course - South Carolina DOT, Columbia, South Carolina

John Turner (May 7-10, 2012): Highway Geology Symposium, Redding, CA

Now Published! NCHRP Synthesis 418–Developing Production Pile Driving Criteria From Test Pile Data

By Robert Thompson, on September 14th, 2011

The Transportation Research Board of the National Academies has published a National Cooperative Highway Research Program synthesis report by Dan and Robert: NCHRP Synthesis 418–Developing Production Pile Driving Criteria From Test Pile Data. This synthesis provides a survey of the current practices used by transportation agencies to develop pile driving criteria, with special attention on the use of test pile data. The report covers issues related to developing driving criteria, the current practices used by the responding agencies, recommended useful practices that were identified, along with descriptions of the practical approach several agencies use to integrate a range of technologies to develop pile driving criteria under typical conditions. The information collected indicates that practices used by transportation agencies to develop pile driving criteria for production pile installation can be described as highly variable in terms of the level and sophistication of the testing performed.

Included in the report are:

Responses from a survey sent to all 50 state departments of transportation plus the District of Columbia and Puerto Rico (44 of the 52 agencies provided responses).
Interviews performed by telephone or in-person of nine of the responding agencies selected based on the written survey responses.
A comprehensive literature review on the range of practices included in test pile programs and their use in developing production pile driving criteria.
Discussions of the survey results.
Useful practices identified from the surveys.
Identification of research needs for this topic.

To purchase the print version of this report or get a PDF, follow this link to TRB. Click the “View This PDF” to get the PDF.

Please note that if you order the printed version, Appendices B and C (copies of the completed survey forms and interview notes) are available via download only.

Dan To Receive 2011 DFI Distinguished Service Award

By Robert Thompson, on August 31st, 2011

Dan will be honored at the DFI 36th Annual Conference on Deep Foundations in Boston, October 19 to 21. He will receive the award at the annual awards banquet on Thursday, October 20th. From DFI:

The Deep Foundations Institute is pleased to announce Dan Brown, P.E., Ph.D., as the recipient of the DFI 2011 Distinguished Service Award. The award, in its 31st year, honors individuals chosen by their peers for exceptional contributions to DFI and to the industry.

Brown began his career with a B.S. from Georgia Tech, and later received his Ph.D. at the University of Texas, Austin, in only 28 months, while working. He then taught at Auburn University for 22 years before setting up his own consulting firm in Tennessee. The Winter 2011 issue of the DFI magazine included a profile of Brown that chronicled the universal admiration and regard for him within the industry. He was cited by others for his expertise, his intelligence and ability to teach others. Brown and his firm are sought out for advice everywhere.

Follow this link to see the full press release. We’ll post pictures after the ceremony.

Simplified Settlement Model–DFI Journal Technical Note by Tim Siegel

By Robert Thompson, on August 25th, 2011

Tim has authored a Technical Note in the most recent issue (June 2011) of the DFI Journal. The note is entitled “Simplified Settlement Model for a Shallow Foundation on Composite Ground with Rigid Piles”. From the Abstract:

A piled raft refers to a shallow foundation that is structurally connected to the piles, while composite ground refers to a soil-pile matrix where the piles are not structurally connected. The design objectives for both a piled raft and composite ground are (excluding special considerations such as expansive soil): (1) to provide a sufficient ultimate resistance and (2) to distribute the load into the soil-pile matrix so that the settlement experienced by the shallow foundation is within tolerable limits. A simplified model is proposed for a shallow foundation on composite ground where the foundation settlement is estimated as the sum of the downward movement of the piles plus the downward movement of the shallow foundation relative to the pile head. The proposed simplified
model is applied using conventional geotechnical analyses for two hypothetical examples of shallow foundations undergoing compression settlement.

This paper was originally published in DFI’s bi-annual journal, Volume 5, No. 1 in June 2011. DFI is an international technical association of firms and individuals involved in the deep foundations and related industry. The DFI Journal is a member publication. To join DFI and receive the journal, go to www.dfi.org for further information. ”

You can also subscribe to the DFI Journal here.

Audubon Bridge–Cofferdam Construction Article

By Robert Thompson, on July 31st, 2011

As noted earlier on this blog, the Audubon Bridge opened a little bit earlier than planned. Although over a year old, an article recently came to my attention that puts a spotlight on the unique engineering and construction that went into the cofferdams for the two main bridge piers in the Mississippi River. The article is “John James Audubon Bridge Project – Cofferdam Construction for the Main Span Pier Foundations”, published in the February 2010 issue of Louisiana Civil Engineer, the Journal of the Louisiana Section of the American Society of Civil Engineers.

The article’s lead author, Sereno Brown, P.E., was the construction team’s Project Engineer for the design-build project. In the article, Mr. Brown outlines the issues that led to the team selecting a pre-cast concrete cofferdam over other methods, the design methodology, and then the construction of the cofferdam. The effort posed several significant design and construction challenges, including the sequence of lowering the cofferdam into place through a set of hydraulic jacks. The entire process was truly an amazing engineering and construction feat.

Download the article here.

ADSC Lawrenceville Test Site–Prediction Contest!

By Robert Thompson, on July 26th, 2011

Update (7/31/11) – Field Day set for Thursday, August 18th – More info here!

Back by popular demand, we will hold a prediction contest for the second test site in the ADSC drilled shaft research project for rock sockets in the Southeastern U.S. Contestants are encouraged to download the information linked below and then submit their predictions of unit side resistance and base resistance that will be measured by the O-cell tests. The winner will be announced at the field test and demonstration day on site, as well as published in this blog along with all submitted predictions.

Two test shafts will be installed July 26 – 29th at the yard of Foundation Technologies, Inc. One will include a rock socket to attempt to test side and base resistance in the rock socket. The other shaft will be drilled to “rock auger refusal” to attempt to test side resistance in the partially weathered rock (locally termed PWR) and base resistance at “rock auger refusal”. In the Piedmont area, the highly weathered upper rock zone is commonly called PWR. Another common usage is “rock auger refusal” to define where “hard rock” begins. It is thought that designers may be overly conservative with base resistance values at “rock auger refusal”. Hopefully this test will provide useful data in that regard.

Testing will occur during a field demonstration day in mid-August. We’ll post the date once it is finalized.

Information to include the test shaft configurations and exploratory boring data can be downloaded here.

The contest entry form along with instructions for submission can be downloaded here.

We will have Aaron on site to observe and take lots of pictures. We’ll post his photos of the excavations as soon as we can (check the project web page soon after August 1st) to assist in making predictions.

All predictions must be submitted by the close of business, August 12, 2011.

For more information, visit the test site page.

Previous posts.

Audubon Bridge Opened To Traffic (earlier than planned!)

By Robert Thompson, on July 20th, 2011

The John James Audubon Bridge was opened to traffic on May 10, 2011 a little earlier than planned. While the project is not 100% complete, the bridge was sufficiently complete to allow an emergency opening due to closure of the nearby ferry the bridge is replacing. From the project website:

Due to the high level of the Mississippi River causing the closure of the New Roads/St. Francisville ferry, the Louisiana Department of Transportation and Development (DOTD) opened the John James Audubon Bridge at 10 a.m. on Thursday, May 5, 2011. This emergency opening allowed continuous river-crossing access for traffic affected by the ferry closure. The ferry, which carried approximately 720 vehicles per day according to 2009-2010 DOTD statistics, is permanently closed with the opening of the Audubon Bridge.

Construction is still ongoing and could affect traffic until the project is 100% complete later this year.

ADSC Load Test Research – Lawrenceville, GA Site – SCHEDULE UPDATE

By Robert Thompson, on June 27th, 2011

The planned second load test in the ADSC research project for rock sockets in the Southeastern U.S. is moving closer to execution. Bruce Long of Long Foundation Drilling Company provides this update:

To Fellow Load Testers,

We want to thank everyone who submitted questions or comments regarding the preliminary load test program submitted to us by Dr. Dan Brown. Those comments, and more, will be considered while fine-tuning the program.

Because we have several companies donating their time and money, we have to be flexible with respect to the installation and testing dates. We have tentatively selected some dates, but these are subject to change depending upon the workloads of those volunteering their efforts. We hope to begin shaft installation during the last two weeks of July (weeks beginning the 18^th or 25^th). The actual load testing would probably take place the week of August 8^th, with the actual test date being decided upon by sometime in early July (I hope to give everyone at least a 3-4 week notice).

The actual test date would include a field day visit by all interested parties to the test site at Foundation Technologies office in Lawrenceville, GA. Activities will include a load testing discussion led by Dr. Dan Brown, along with lunch. We would then move to the test site where Loadtest, Inc. will be conducting the Osterberg Load Test on our first shaft. A discussion of the testing process and procedures by Loadtest will precede the actual testing (We will be submitting information later regarding a load test contest where each of you will get to predict the outcome of the test with a special prize going to the winner). We also hope to be drilling on the second shaft that day and will be discussing the drill rigs, tools, and other equipment being used, as well as having the other Osterberg cell available for viewing. This site visit proved to be very well received when we did it in Nashville at the last load test. We hope for a big turnout that day.

I wanted to give everybody a brief update and will be in touch when additional information becomes available in the near future. Thank you for your interest, and if anyone has any questions regarding this plan, please feel free to call me at your convenience.

Bruce Long

President

Long Foundation Drilling Co.

Previous post is here.

The test site page is here.

The main page for the research project is here.

Dr. Erik Loehr, P.E. Receives ADSC Award

By Robert Thompson, on June 13th, 2011

Dr. Erik Loehr, P.E. was honored by the ADSC with the ADSC Outstanding Service Award, presented at the President’s Luncheon at their 2011 annual meeting in New Orleans, Louisiana (Feb 1 –5, 2011). The award recognized Erik’s research in the use of micropiles for slope stabilization and as foundations. From the March/April 2011 edition of Foundation Drilling:

ADSC’s Outstanding Service Award was garnered by Dr. J. Erik Loehr, University of Missouri, in acknowledgment of his research and educational efforts that advance the technical aspects of the drilled foundation and anchored earth retention industries.

Dr. Loehr is currently on the faculty of the University of Missouri and is a consultant with DBA.

ADSC Rock-Socketed Drilled Shafts in the SE Research Project Site No.2 – Comments Welcomed

By Robert Thompson, on May 9th, 2011

After some lengthy delays, the rock-socketed drilled shaft research sponsored by the Southeast Chapter of the ADSC is back on track. A second site has been selected at the site of Foundation Technologies, Inc. in Lawrenceville, Georgia. This site will investigate the resistance of some of the rocks of the Piedmont for drilled shaft design. The first test site was in Nashville, Tennessee. The report of the first test site and other information can be found at the test site page. General information about the complete project, including a list of participating/contributing companies and organizations, can be found at the project page.

Bruce Long (Long Foundation Drilling Company) is the lead for the ADSC on this project and has requested interested parties to provide comment on the test plan for the second site (see links below). The hope is to have load testing occur this July if every thing comes together properly. Bruce sent the following email with some refresher material on the Nashville test site and an update on the startup for the Lawrenceville site:

First, I would like for everyone to know that the load test program jointly planned between the Atlanta area ASCE Geotechnical community and the Southeast Chapter of the ADSC is alive and well despite some longer than planned delays. The final boring data has been in hand for some time and Dan Brown and his group have reviewed this information and submitted a preliminary load test program for review and comment. This program is very similar to the test program that was performed in Nashville a couple of years back. For informational purposes, the results of that test program has resulted in an increased awareness of the available load carrying capacity in the limestone formations in the area. Historically, shafts were designed almost exclusively utilizing end bearing with the normal range of values allowed ranging from 60-100 KSF. In recent months, we have seen projects now being designed with recommended values ranging from 100 up to 250 KSF with an increasing number of designs also relying on skin friction values up to 25 KSF in sound limestone sockets. The information gained from these load tests has given area engineers increased confidence in raising the bar for future drilled shaft designs. This will result in lower foundation costs for owners of public and private projects alike. For those involved in the design process, better information will result in improved design values and an improved competitive position for those willing to utilize this data.

Now we are prepared to move forward with the planned testing in the Atlanta area. I have attached the final geotechnical report for your review. There are several people and companies that have generously volunteered their time and expertise to make this happen, Todd Barber with Geo-Hydro Engineers, Inc. being the most notable of these. His persistence and assistance was invaluable. Others that contributed in a variety of ways include Mactec, Golder Associates, Georgia Tech and GeoTesting Express. Thanks to everyone for their efforts.

Also attached is the preliminary memo from Rob Thompson of Dan Brown and Associates. What he has outlined are suggestions based upon the boring information for two separate Osterberg Load cell tests. One would be on a shaft that was hand-cleaned, while the second shaft would be machine-cleaned only. This would allow a comparison to determine the effects (if any) that traditional hand-cleaning has on shaft behavior. This memo is being sent out with the intention that review and comments from the geotechnical community be considered and incorporated in the final program. Depending upon the extent of comments, a final meeting could be necessary to discuss any proposed revisions. If suggestions are minimal, such a meeting might not be required. In this case, we would proceed with shaft installation and testing as soon as possible.

Thanks for your patience–I think that the final results will be worth the time. It has been very rare that full scale load testing be done in hard rock areas (Piedmont or Limestone), but if the results of our Nashville area testing are any indication, I think the results will definitely show that the effort was worthwhile.

Please take time to review this information and e-mail or call me with any comments that you might have. As soon as all comments have been reviewed, we will let everyone know our plan to proceed. I would like to have comments submitted to me by May 27, 2011. If there are any questions regarding our plans, schedule, etc., please feel free to contact me at your convenience.

I have linked the proposed load test plan memo and the boring information below. Bruce would like comments from interested parties to be submitted by May 27, 2011. Please submit comments to him at blong@lfdc.com.

A blog page for this test site has been created and will be updated as the project progresses. We intend to have a prediction contest similar to the one we had for the Nashville site, so keep checking for information. Better yet, subscribe to our blog using one of the social media links at the top of the right sidebar of the blog.

Load Test Plan Memo from Dan Brown (20 May 2010)

Summary of Test Borings from GeoHydro Engineers (26 Jan 2010)

LRFD Design Procedures Case Histories – Iowa ASCE Geotechnical Conference

By Robert Thompson, on March 24th, 2011

Paul gave a presentation recently at the Iowa ASCE Geotechnical Conference where he discussed two project case histories for LRFD design of bridge foundations. The meeting was held March 3, 2011 in Ames, Iowa. In his presentation, Paul gave an overview of the LRFD design procedure as it applies to foundations, reminding them that LRFD is not difficult and that it provides a logical framework for incorporating reliability into foundation design. Paul talked about our experiences using LRFD for foundation design for two bridges over the Mississippi River: the Hastings Bridge in Hasting Minnesota and the new I-70 bridge in St. Louis, Missouri. Both bridges are currently under construction.

A PDF of his presentation can be found at the link through the image below, or on our Presentations page.