This is the second report from their research project on rock-socketed drilled shafts in the Southeast U.S.  This report is from the Lawrenceville, Georgia test site where shafts constructed in metamorphic rock of the Piedmont geologic . . . → Read More: ADSC SE Chapter Lawrenceville Test Site Report Published]]> The report for the ADSC Southeast Chapter Lawrenceville, Georgia Test Site is complete and published (link below).

This is the second report from their research project on rock-socketed drilled shafts in the Southeast U.S.  This report is from the Lawrenceville, Georgia test site where shafts constructed in metamorphic rock of the Piedmont geologic province were load tested using the O-Cell load test device.  The report link is below.  Additional information about the test site can be found at the Lawrenceville Site Page.

The first site of this project was in Nashville, Tennessee where shafts constructed in limestone were tested.  Information on the Nashville Site and the test reports can be found at the Nashville Site Page.

Both reports will be the feature of a paper and presentation by Robert at the 2012 ADSC Expo, March 13-17, in San Antonio, TX. More information about the Expo can be found here.

Thompson, W.R., Brown, D.A., and Hudson, A.B. (2012). “Load Testing of Drilled Shaft Foundations in Piedmont Rock, Lawrenceville, GA, Report for ADSC Southeast Chapter, January, 2012.

As massive concrete piers rise from the Mississippi river in southeast Minnesota, people have begun to take notice of what will become the longest free-standing tied-arch bridge in North America.  A unique project in several respects, the new Hasting bridge has recently been featured in articles on the websites of ENR . . . → Read More: Hastings Bridge Receives Press as Foundations Near Completion]]>

As massive concrete piers rise from the Mississippi river in southeast Minnesota, people have begun to take notice of what will become the longest free-standing tied-arch bridge in North America.  A unique project in several respects, the new Hasting bridge has recently been featured in articles on the websites of ENR and Roads & Bridges.  The ENR article is a republication of an article that originally appeared in the Minneapolis Star Tribune highlighting the construction process of the last year, with particular focus on the process of constructing the river piers.  The Roads & Bridges article is a more technically in-depth piece written by the lead bridge engineer Vincent T. Gastoni, P.E., of Parsons Transportation Group.  Both articles discuss some of the many geotechnical changes faced on this project.  This excerpt from Roads & Bridges is a concise description of the pier foundations and some of the reasoning behind their selection:

The main river piers are concrete delta-style frames with the tied-arch superstructure fully framed into the pier through the knuckle connection. The stiffness of the foundation system was then integral to the overall force effects in the structure. The north pier is located in 190 ft of soft soils overlaying rock and supported on unfilled 42-in. driven steel pipe piles. Drilled shafts were investigated early but were not cost-effective, impacted the schedule and presented a risk to the existing bridge due to potential caving effects. Statnamic pile load testing was used to validate the vertical capacity and lateral performance of the 42-in. piles. The south pier footing is close to the rock surface; however, the rock was deeper, more sloped than expected, and the originally planned spread footing was changed to short drilled shafts during the final design. Dan Brown & Associates provided the team with geotechnical analysis and recommendations.

Our Tim Siegel pointed out that the statement “It’s a marvel of engineering that requires ingenious construction techniques, most of which are invisible to the drivers whizzing by overhead,” from the Star Tribune, is an accurate description of how our work as foundation designers and constructors is often viewed.  Although much of the ingenuity and innovation that goes into the geotechnical aspects of projects often goes unnoticed by the general public, it is certainly refreshing to see articles like these.  For us at DBA, it is even more refreshing to see our efforts credited by name as they were in the article by Vince when he wrote, “Dan Brown & Associates provided the team with geotechnical analysis and recommendations.”

For a design-build project with so many different geotechnical components (driven piles, drilled shafts, spread footings, retaining walls, a column-supported embankment, and light weight fill), it is hard to believe that our role as the lead geotechnical engineer is nearing completion just a little over a year after construction began.  At this point, the only foundations that have yet to be constructed are some of the rock bearing spread footings at the south approach.  DBA will also monitor instrumentation installed in the column-supported embankment for the next two years.

Previous blog posts by Aaron and David can be found here:Hastings Bridge Update and Hastings Update and Photo Album.  Additional information can be found on the DBA project page here.

Dan and Steve co-authored an article in the Fall 2011 issue of Deep Foundations (from DFI) that covered the foundations for the recently completed record-setting Audubon Bridge in Louisiana.  Dan and Steve cover not only the shaft testing, design, and construction, but also the unique cofferdam used for the tower foundations.  I . . . → Read More: Audubon Bridge Foundations in Fall 2011 “Deep Foundations”]]>

Dan and Steve co-authored an article in the Fall 2011 issue of Deep Foundations (from DFI) that covered the foundations for the recently completed record-setting Audubon Bridge in Louisiana.  Dan and Steve cover not only the shaft testing, design, and construction, but also the unique cofferdam used for the tower foundations.  I recently highlighted an article by Sereno Brown, P.E. of Flatiron that covered the design and installation of the cofferdam in detail. 

You can receive Deep Foundations every quarter (soon bi-monthly!), as well as the DFI Journal, by joining DFI.  Get information on joining at this link – click on “Membership” at the top banner.

Last year I had a football themed post (college football, in case you were wondering…and that is American football for our fans outside . . . → Read More: Happy Karl Terzaghi’s Birthday 2011!]]> Greetings to all Terzaghi fans!  Yes, it is that time of year again, where our thoughts turn to the anniversary of the birth of one of the greats in our field.

Last year I had a football themed post (college football, in case you were wondering…and that is American football for our fans outside the U.S.) since Terzaghi’s birthday was on a Saturday. Since I am not a big pro football fan, and since I used football last year, I figured I would do something different for this year’s weekend post.

The August 2011 edition of the International Society for Soil Mechanics and Geotechnical Engineering ISSMGE Bulletin is headlined with an article on the history of ISSMGE: “THE ISSMGE FROM 1936 TO 2011 A RETROSPECTIVE ON THE OCCASION OF THE 75TH PLATINUM JUBILEE ANNIVERSARY” by Kenji Ishihara and Michele Jamiolkowski. The Bulletin is in two parts at this link. The article is an outstanding work providing an excellent account of the start of ISSMGE as an international conference and its evolution into the ISSMGE we know today.

It should be no surprise that Prof. Terzaghi was very active and one of the key figures in the formation and success of ISSMGE, which began as the International Conference on Soil Mechanics and Foundation Engineering (ICSMFE). Many of the giants of soil mechanics and geotechnical engineering on which we base al of our work were instrumental in the start of ICSMFE and its impacts on our profession. As for that time in history (1936) and how it was important to our field:

The time had come to hold a Conference aimed at exchanging and sharing information on Earth and Foundation Engineering.

It was Professor Arthur Casagrande (assistant professor of Harvard University) who sensed the timing, conceived the idea and carried out the herculean task of running the conference all the way through, in his role of Secretary General, with K. Terzaghi (Professor of Technical University of Vienna and visiting Professor of Harvard University) as Chairman. Professor Peck once remarked “Our Society owes an enormous debt to Arthur Casagrande for his conviction that the time was right for the International Conference and to his tremendous efforts to organize it“.

…

Since the first ICMSFE was so successful, it became clear that the Conference should not remain a one-off event but should, instead, be continued within a few years, possibly being held in Holland where earthwork engineering is so crucial to the country.

It was also requested to set up a permanent international organization. Thus it was decided to establish International Committees consisting of National Committees with K. Terzaghi as President and A. Casagrande as Secretary. It was also decided that at the next Conference the International Committees would submit the draft of the Constitution and of the By-laws, which are essential for the Society to become a permanent organization.

There was at that time a widespread awareness that it was the moment to set up a common denominator institution that would group engineers with diverse backgrounds but involved in our discipline.

Portion of group photo from 1st ICSMFE, 1936.  (From ISSMGE Bulletin Vol 5, No 4, August 2011, p3)

Photo of Terzaghi addressing the opening session of the 4th ICSMFE, 1957.  (From ISSMGE Bulletin Vol 5, No 4, August 2011, p7)

And the rest, as the saying goes, is history!

As an editorial note on the first year, Ishihara and Jamiolkowski offer this observation:

It is commonly recognized that K. Terzaghi is the originator of modern soil mechanics and foundation engineering and therefore father of our profession. After tracing the history of development, the writers had a strong belief that this is true. Not only was he always a leading figure in the forefront, but he conveyed strong messages on the role and importance of the soil mechanics and foundation engineering every time he participated in the ICSMFE. We are very much impressed by his enthusiastic and heartfelt message to our community.

No less important was the role played by Arthur Casagrande. He was instrumental in persuading the President of Harvard University to host the conference and carrying out all arrangements for organizing the first International Conference on Soil Mechanics and Foundation Engineering. The great success of this conference contributed greatly for establishing the place of soil mechanics in engineering practice throughout the world. He also dedicated himself to the ISSMFE as the 3rd President between the periods of 1961 in Montreal to 1965 in Paris.

There is a saying that for a great religion to be established, there always are two key-role playing giants. For Christianity Jesus Christ is the originator and his disciple Saint Paul was the great evangelist. For Greek philosophy, Socrates was the great philosopher and it was Plato who was the greatest disciple. Terzaghi and Casagrande are considered as a combination in the same context. Without Terzaghi, Casagrande would not have been so well-known. Had there not been Casagrande, the fame of Terzaghi would have developed in a different format.

Now neither I nor the authors are suggesting that soil mechanics is a religion, but their point on the timing and combination of Terzaghi’s and Casagrande’s work was critical to what we see as the field of soil mechanics/geotechnical engineering today. Without these two and others seeing a need, taking charge, and filling that need, we could very well be viewing things from a completely different framework.

So as we reflect on this celebrated day, let’s remember not only Prof. Terzaghi’s great technical achievements, but also his role as a leader (along with many others) shaping our field of practice and our professional societies.

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 . . . → Read More: Dan To Receive 2011 DFI Distinguished Service Award]]>

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.

A piled raft refers to a shallow foundation that is structurally connected to the piles, while composite . . . → Read More: Simplified Settlement Model–DFI Journal Technical Note by Tim Siegel]]> 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.