Drilled Shaft Construction | Dan Brown and Associates, PC

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.

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)

Hastings Update and Photo Album

By David Graham, on April 1st, 2011

Well, I, David, have survived my first (and hopefully last) winter in Minnesota. I spent most of January and February observing the installation of the Pier 5 drilled shafts at the new Hastings bridge project in Hastings, Minnesota. In addition to the drilled shafts, there has been a lot activity at Hastings since Aaron last blogged about this project in January. A link to his post is here. All of the ground improvement piles for the column-supported embankment have been installed and approximately 75% of the caps have been poured. The 42-inch piles and pile caps for Piers 8, 9, and 10 are also complete. Piles for the north embankment retaining wall have been installed and construction of the wall has begun. Excavation for the rock bearing spread footings that will support the south land piers is in progress. Work at Piers 6 and 7 and on the north shore are currently on hold as the Mississippi River is experiencing its annual spring flood. The water level is about 14 feet above normal elevation.

I have taken the pictures Paul and I have collected over the last few months and uploaded some of the more interesting ones to a Picasa web album. The pictures are generally in chronological order and cover most of the construction process from November of 2010 right up to the end of March 2011. A link to our our video of a Statnamic load test at Hastings that Aaron blogged about is here.

Audubon Bridge Closure–The Span is Complete!

By Robert Thompson, on February 1st, 2011

On December 29, 2010, Audubon Bridge Constructors recently “closed” the main span of the John James Audubon Bridge between New Roads and St. Francisville, Louisiana. Watch the video featured at the top of the page at the bridge link to hear about the bridge, including the drilled shaft foundations! For something really fascinating, go to the webcams here and scroll back through the various dates. They have archived images all the way back to start of construction.

Photo: Chris Usery, Figg Bridge Inspectors

The last cables were installed on January 3, 2011 as noted on the project website:

The last two cable stays of the longest cable-stayed bridge in the Western Hemisphere were installed on January 3, 2011, five days after the spans were connected. The John James Audubon Bridge, Louisiana’s newest crossing over the Mississippi River, now has all of its 136 cable stays in place.

This bridge will be the longest cable-stayed bridge in North America when it opens later in 2011. Again, from the project web site:

The spans of the longest cable-stayed bridge in the Western Hemisphere were connected on December 29, 2010, stretching 1/3 of a mile over the Mississippi River. The John James Audubon Bridge, connecting Pointe Coupee and West Feliciana parishes in Louisiana, is approximately 92% complete. Construction of the spans began from both sides of the 500-foot tall towers earlier this year. Both sides continue to progress at a rapid pace, and now the meeting of the spans has occurred.

Steve Dapp and I had the pleasure of working with many great people during our time on site (much more time for Steve than for me!) during foundation construction. One of them, Chris Ursery of Figg Bridge Inspectors, has been great about providing us with photos now and then to keep us updated of some of the details of the bridge construction. Chris has granted us permission to share a few of his recent photos, which are shown below or can be seen in our web albums here.

Previous post on Audubon Bridge.

kcICON Project Opens Ahead of Schedule

By Robert Thompson, on January 3rd, 2011

The kcICON project in Kansas City has been completed six months ahead of schedule and within budget with all lanes and ramps being open on December 18th. Demolition has begun on the existing Paseo bridge. You can see some photos of the demolition (like the one in this post – thanks kcICON!) at their Facebook page. It was a great experience for us to have been a part of this project. If you want to see all of our previous posts on this, click here. Other points of interest are linked below.

The Kansas City District of MoDOT

New I-70 Bridge Featured in Foundation Drilling Magazine

By David Graham, on December 10th, 2010

The new I-70 bridge over the Mississippi River near St. Louis, Missouri is quite the project. When completed, it will be the third longest cable-stayed bridge in the United States, with a 1,500-ft main span. Most significantly for the geotechnical community, the bridge made history when one of its 11-ft diameter drilled shafts resisted a world record breaking 36,000 tons (bi-directional) during an O-cell load test. The bridge has already seen press in Civil Engineering Magazine (July 2010, page 30-32), at ENR.com, and in a post by Robert on this blog. Now, an article by DBA’s Paul Axtell is featured in the September/October issue of Foundation Drilling Magazine. The editor summarized the article saying:

The information in the following article is a composite of material that came to Foundation Drilling Magazine from three separate sources. Part I is based on information gleaned from an article that was published on the Associated Press news wire. Part II is excerpted from ENR’s August 18th, E-Newsletter. Part III was provided by Paul Axtell and Dan Brown of ADSC Technical Affiliate company, Dan Brown and Associates. The bridge project is of interest in general. The Osterberg Load Cell test will be of particular interest to professionals in the deep foundation industry, and specifically for those who work in the drilled shaft segment.

Axtell, P.J. (2010). “Mississippi River Bridge Project Includes Record Load Test: A Three Part Story”, Foundation Drilling, Vol. 31, No. 7 September/October 2010.

Three Updates: World Record O-Cell Load Test in St. Louis, MO

By Robert Thompson, on August 18th, 2010

Check out the bottom of my post on June 30th World Record O-Cell Load Test for some updates and new links to recent news articles.

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.

World Record O-Cell Load Test in St. Louis, MO!

By Robert Thompson, on June 30th, 2010

DBA was part of foundation engineering and construction history while participating in a drilled shaft load test for the New I-70 Mississippi River Bridge in St. Louis, Missouri. A new O-cell world record of 36,000 tons (bi-directional) was achieved on the test, besting the former record of just under 32,000 tons set in 2005 in Korea (see here).

The test shaft was built by MTA (a joint venture of Massman/Traylor Brothers/Alberici Constructors) as part of an Alternative Technical Concept (ATC) that MTA submitted in their winning bid. During the bid phase, the owner allowed ATC’s to be submitted by pre-qualified teams. These ATC’s were unique to the team that submitted them (e.g., each team was allowed to submit their own ATC’s if they desired, but the ATC’s were not shared amongst all the teams). DBA worked with MTA to develop an ATC that optimized the drilled shaft foundations shown in the “baseline” drawings provided by the owner. That ATC provided a more economical foundation solution that was accepted, bid, and awarded (note MTA also had the option of bidding the “baseline” drawings as-is). A full-scale load test on a dedicated test shaft using the Osterberg Cell (O-cell) test method was included in the ATC to: 1) prove the design values used for the resistance in the rock socket; and (2) take advantage of higher resistance factors for using a load tests as opposed to only calculations. The baseline drawings did not include a load test.

Loadtest, Inc. performed the load test. The bottom-up static load test applied slightly greater than 36,000 tons (bi-directional) to the shaft resulting in about 1/8in of upward movement of the shaft and about the same magnitude of downward displacement at the base. The rock socket was about 23ft deep and 11ft in diameter in very hard limestone. Four 34in O-cells placed at the base of the shaft were loaded to 150% of their rated capacity to achieve the record load.

UPDATE (8/4/10): The bridge was featured in the July 2010 issue of Civil Engineering magazine from ASCE in the “News” section. Follow the link below and then go to Page 30.

Civil Engineering July 2010

UPDATE (8/17/10): Press Release from MTA (contractor joint venture).

UPDATE (8/18/10): ENR.com Article

Bridge updates – kcICON, Audubon, Beck Street

By Robert Thompson, on May 25th, 2010

As geotechnical/foundation engineers, we don’t usually get to see much of what happens on a project after the foundations are completed, especially a project like a large bridge that can take years to complete. Technology such as the Internet, webcams, and digital photography have made it easy for us to see how things are progressing on projects, as well as maybe get images of the completed structure. As I have noted before, some projects are using Twitter and Facebook to keep the public informed on closures, delays or overall project progress as part of good public relations. Her are some updates on a few of our recent projects.

kcICON:

The main span is well underway, including the cables. The kcICON Facebook page is here.

Audubon Bridge:

Check out the webcam. You can download images if you like. YOu can also do a time-lapse from Day 1 of construction.

Beck Street Bridge:

Part of the I-15 Express Link project in Salt Lake City, UT. The photos below I obtained from the photos page on the project web site . We were involved in the design and construction of the foundations for the Beck Street Bridge only.