Get the New FHWA Drilled Shaft Manual
Get the NCHRP Synthesis 418 – Pile Criteria From Test Pile Data
Dan’s Speaking Schedule March 16, 2012 - "Advanced" Design and Construction Issues with Drilled Shaft Foundations; Case Histories - ADSC Equipment EXPO and Technical Conference - San Antonio, Texas
March 26-28, 2012 - State of the Art and Practice for Drilled Foundations - GeoCongress 2012 - ASCE/Geo-Institute - San Francisco, California
Other DBA Team Speaking Appearances
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
Conferences, Meetings, Seminars, Workshops
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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)
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.
Previous Hastings posts
Previous I-70 posts
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.
By Robert Thompson, on January 19th, 2011
(Image source: LakeExpo.com)
DBA is part of a team led by Parsons Transportation Group that was selected to design the replacement of the Hurricane Deck Bridge over The Lake of the Ozarks in Camden County Missouri. MoDOT has awarded the design contract to Parsons. DBA will be the lead geotechnical engineer with Terracon on the team providing drilling and laboratory services, as well as some foundation engineering support services. Parsons was chosen due to the innovative approach the team proposed that includes reusing the existing piers (from ENR.com):
MoDOT chose Parsons for proposing an innovative approach to construction that involves the use of temporary pier widening and shifting the existing superstructure over. This method will allow traffic to be maintained on the existing bridge while the new bridge is constructed, potentially resulting in significant cost savings.
A little history of the bridge can be found at Go2Lakeofthe Ozarks.com, including how it got its name:
Hurricane Deck Bridge of Ozarks crosses the main channel of the lake of approximately mile marker 35. It carries Missouri highway 5 between Versailles and Camdenton. It was built in 1936 –five years after the lake filled. It was named as Hurricane Deck because it was heard that a tornado struck that area which was locally "Hurricanes". It is a nautical term associated with river steamboats. The Hurricane Deck was the uppermost deck which provides and allows everyone to experience the pleasant breezy place and the passing scenery.
Other news links:
Lake News Online – 12/2/2010
Lake Expo.com – 12/2/2010
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
ENR
DBA Project Page
kcICON Facebook Page
kcICON web page
By Robert Thompson, on November 2nd, 2010
Paul received a few photos of the kcICON bridge that are just too cool not to share. These were sent to him by Massman Construction. These were taken in September of this year. MoDOT’s Flicker album of the dedication ceremony is here. The new bridge was dedicated and partially opened to traffic (southbound) on September 27th. The northbound traffic was shifted to the new structure on October 22nd. All of the bridges and ramps for the project will be opened by the end of the year – 6 months ahead of schedule. Can’t wait to see it after the exisitng bridge is demoloshed, though it is a pretty cool image with the old and new bridges together. Updates for the project are on the project Facebook Page.
Click here for previous posts on kcICON.
By Robert Thompson, on November 1st, 2010
 Dan recently played the part of storyteller at the Southeastern Transportation Geotechnical Engineering Conference (STGEC) 2010 conference in Charleston, West Virginia when he gave the lunch presentation on the conference’s first day. He took the audience on a trip down the Mississippi River from a foundation engineer’s perspective, talking about several bridges that DBA has had the pleasure to work on, or is still working on, along the river the last few years. Dan began with the I-35W Bridge replacement in Minneapolis, Minnesota and ended at the Huey P. Long Bridge in New Orleans, Louisiana. Stops along the way included the Hastings Bridge (Hastings Minnesota), the new I-70 Bridge (St. Louis, Missouri), and the Audubon Bridge (New Roads/St. Francisville, Louisiana). Dan covered some of the technical issues/problems associated with each project and the solutions applied to complete the foundations (or complete the design). It was a very informative talk presented in a unique way that everyone at the luncheon seemed to enjoy. Dan’s presentation is now available on our Presentations Page.
Posts on Hastings Bridge here.
Posts on I-70 Bridge here.
Posts on Audubon Bridge here.
Posts on the Huey P. Long Bridge here.
 Immediately after lunch, Robert made a presentation that described some of the pile load tests performed on two of the storm protection projects in New Orleans that DBA was privileged to be involved with through Kiewit. By following Dan, it provided a little continuity to the story as Robert took the group below the Huey P. Long Bridge to the levees and canals downstream of New Orleans. Robert’s presentation can also be found on our Presentations Page.
Post on the pile load tests here.
By Robert Thompson, on October 1st, 2010
October 2nd, is the day we (or at least a lot of us geoprofessionals) have all been looking forward to all year – the birthday of Professor Karl Terzaghi, The Father of Modern Day Soil Mechanics, born October 2, 1883.
Since this historic day in geotechnical engineering history falls on a Saturday this year, I offer a cheer for those of us into college football (I mean, really, who isn’t this time of year, at least in the U.S.):
Two bits, four bits, six bits..a dollar
All for Terzaghi, stand up and holler!!!!!
On the more reflective side, each year I try to find some interesting fact or quote to write about. This year, I decided to read the preface of Soil Mechanics in Engineering Practice (Terzaghi and Peck, 1948) for inspiration, and thus will quote from there:
“Unfortunately, the research activities in soil mechanics had one undesirable psychological effect. They diverted the attention of many investigators and teachers from the manifold limitations imposed by nature on the application of mathematics to problems in earthwork engineering. As a consequence, more and more emphasis has been placed on refinements in sampling and testing and on those very few problems that can be solved with accuracy. Yet, accurate solutions can be obtained only if the soil strata are practically homogeneous and continuous in horizontal directions. Furthermore, since the investigations leading to an accurate solution involve highly specialized methods of sampling and testing, they are justified only in exceptional cases. On the overwhelming majority of jobs no more than an approximate forecast is needed, and if such a forecast cannot be made by simple means it cannot be made at all.”
While our technology has allowed us to measure, analyze, test, and compute huge volumes of data, as well as investigate the highly complex nature of soil-structure systems, we sometimes get caught up in the details of precision. We try to be much more precise than the materials we work with truly allow. This is not to say we should totally throw away our technology, forsaking numerical models, design software, or sophisticated in-situ testing and return to the days of slide rules (though I can use one!). There are many times, however, that an “approximate forecast” is just as “accurate” as a calculation computed to a precise number.
So, my friends, raise your glasses this weekend to toast Professor Terzaghi and our profession!
Cheers!
Update (10/1/10): One of my (Robert’s) mentors at my first job out of grad school, Luther Boudra, P.E. at MACTEC, wrote me this morning on the subject of accuracy and precision. I asked him if I could share his comment (and he agreed) since I thought it was very insightful:
Robert, Professors Terzaghi’s comments remind me of something I read recently in a book about precision shooting, particularly at long range. The author, who incidentally is both an engineer and top level shooter, was noting the difference between “precision” and “accuracy”. Precision is exemplified by being able to repeat something to close tolerance, as exemplified in the shooting community by benchrest shooters, who are primarily interested in shooting small groups of typically 5 to 10 shots. Hitting near the center of the target, whatever it is, is of secondary importance. Accuracy, on the other hand, requires the ability to hit what you are aiming at, precisely. In other words to take this to our field of endeavor, it’s possible to be “precisely inaccurate”, which the various software packages available to calculate almost anything enhance the possibility of.
Speaking of slide rules, their greatest attribute is that you have to be able to estimate the answer, rather than just writing down what shows up on the display screen.
By Robert Thompson, on August 30th, 2010
 The Lunda/Ames design-build joint venture (Lunda Construction Company of Black River Falls, Wisconsin and Ames Construction, Inc. of Burnsville, Minnesota) has been awarded a contract to build the new Highway 61 Hastings Bridge over the Mississippi River in Hastings, Minnesota. Parsons Transportation Group is the designer and DBA is performing geotechnical design of the bridge foundations and settlement mitigation as a sub-consultant to PTG.
Here is the existing bridge that is being replaced (viewing from upstream):
In addition to several relatively large approach spans, the new bridge will include a 545ft long free-standing arch main span with four lanes of traffic and a 12 foot wide common use pedestrian/bike path. The new bridge will allow additional parking and an artistic plaza area south of the river. An anti-icing system will be installed to help achieve the 100-year design life.
On the south side of the Mississippi River, the bridge foundations will consist of spread footings bearing on dolostone bedrock. The remaining bridge foundations will utilize 42in diameter pipe piles. Several Statnamic load tests, both axial and lateral, will be performed by our friends at AFT.
Settlement mitigation is required beneath the North Embankment due to several relatively thick and deep strata of compressible fine-grained soils. The embankment will also be heavily instrumented to evaluate performance of the embankment and mitigation technique.
Preliminary work including subsurface investigation has begun. The subsurface investigation is being performed by Braun Intertec under sub-contract to DBA. Test piles will be installed in early September, 2010 with subsequent load testing soon after.
The awarded design-build contract is for $120M. The estimated project completion date is May 13, 2013.
DBA Project Page here.
Mn/DOT Hastings Bridge Project Home Page
Here is a sampling of the local news on the project award:
Hastings Star-Gazette: Many articles, ongoing
9/22 Star Tribune: New Hastings Bridge is on the way
July 1 South Washington County Bulletin: Bridge design chosen: It will be the tied-arch
July 1 Minneapolis/St. Paul Business Journal: Lunda/Ames team wins $120M Hastings Bridge contract
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
 
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