An article by Eric and Dan on the use of micropiles for slope stabilization has been added to our Publications Page. Published in the August 2010 issue of Foundation Drilling Magazine, the article summarizes key findings and recommendations from a study that reviewed and evaluated existing micropile design methods. A new design method is proposed to better predict the mobilized resistance of micropiles used for slope stabilization. The full report prepared by Eric and Dan for the joint ADSC/DFI Micropile Committee, “A Method for Predicting Mobilization Resistance for Micropiles Used in Slope Stabilization Applications”, presents the details of this study. Robert previously posted about this report here.
Category Archives: DBA News
Loehr, J.E. and Brown, D.A. (2010). “Design of Micropiles for Slope Stabilization”, Foundation Drilling, Vol. 31, No. 6 August 2010.Paper by Paul Axtell added to Publications
A paper by Paul Axtell and others on shear strength of cement-bentonite grout mixes has been added to our Publications Page.
New Bloggers at DBA
I (Robert) will now have some help with posting to the blog. Our two young staff engineers, Aaron Hudson and David Graham, will be helping me with blog maintenance and posting content. Until now, I have pretty much written all of the posts and have done all other content updates. Now you will see some new “by lines” on blog posts in the future. Thanks for reading!
A Foundation Engineering Trip Down the Mississippi River
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 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.
DBA Technology Update: We’re on LinkedIn!
Yes, technology fans, DBA is at it again. We are doing all we can to keep up with the ever changing world of social networks, business networks, and communicating via electronic media, we are even using my csgo boosting dot com to bring our business game up. To that end, DBA has a company page on LinkedIn. If you want to see the new technology out there and all the news, then check out www.maxishare.net.
We still have a bit to do to complete our profiles, both corporately and individually, but we’ll get there, we recently read the best wireless router reviews and we think we will be doing an upgrade pretty soon. To help all of you media-savy folks, we have placed a LinkedIn button with all of the other social media icons at the top of our right sidebars. We are looking forward to getting connected!
DBA on team for New Hastings, MN Bridge
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.
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
New FHWA Drilled Shaft Manual is Done!
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!
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.
UPDATE (8/17/10): Press Release from MTA (contractor joint venture).
UPDATE (8/18/10): ENR.com Article
New Project Summaries Added
I have added some new project summaries to our Consulting Projects list. I have also revised/updated the individual project pages we have, plus the Consulting Projects and Research Projects pages.
The projects I have added are:
Beck Street Bridge over I-15, Salt Lake City, Utah
Hurricane Protection Projects, New Orleans, Louisiana
I-70 Mississippi River Bridge Test Shaft, St. Louis, Missouri
Artistic Construction Photo Contest – Volume 1
With all of us visiting construction projects across the country, occasionally we take a photo that appears to be somewhat “artistic” – maybe the lighting (or lack of), or the aspect. I have assembled a few such photos submitted by DBA engineers in the first installment of the DBA Artistic Construction Photo Contest. Included in this installment are such items as: “Daybreak on Night Shift at JJA” and “Fountain” by S. Dapp, the series “Evolution” by P. Axtell, “GI Rig at Sunset” by T. Siegel, and “Piles in the Mist” by R. Thompson. This first volume has more photos of mine than others, but we’ll work on better balance in future volumes.
Feel free to “vote” for your favorite in the comments. I’ll try to update periodically as we have more “worthy” photos!