Tag Archives: Load Test

Bridge Construction, Bridge Foundations, Drilled Piles, Drilled Shafts, Driven Piles, Dynamic Testing, Foundation Testing, Load Testing

Pre-Bid Load Testing for the Mobile River Bridge and Bayway Public Private Partnership (P3) Project

DBA has been fortunate to be involved as a consult to Alabama Department of Transportation (ALDOT) for the  Mobile River Bridge and Bayway Project.  This project represents Alabama’s largest ever investment for a single infrastructure project.  The project includes a cable stayed bridge over the Mobile River and seven miles of bridge over Mobile Bay.  Bridge foundations therefore represent a major component of the estimated $2 billion project cost.  DBA serves as a foundation consultant under subcontract to Thompson Engineering, Inc..  Thompson is one of the ALDOT Advisory Team partners, the other partners being HDR and Mott MacDonald.

With the tremendous volume of foundations required for the project, the DBA/Thompson team worked with ALDOT’s Geotechnical Division to develop a pre-bid load test program to help reduce some of the risks that would face both ALDOT and prospective concessionaires.  Performing a deep foundation load test program during the procurement phase of a Public Private Partnership (P3) project can help the prospective concessionaires better define foundation design parameters and reduce uncertainties and risks related to constructability of the foundations.  The reduced risk leads to reduced costs by allowing the concessionaire to develop a more efficient design while minimizing contingency costs and potential delays related to foundation constructability or performance.

The load test program was designed to include the most likely foundation types that the prospective teams might use.  Several types of driven piles were installed and tested, including typical square and cylinder concrete piles used on the Alabama coast plus steel H-piles and an open-ended steel pipe pile.

All driven piles were subject to dynamic testing with a Pile Driving Analyzer during driving.  Restrikes with dynamic testing were conducted on all driven piles to evaluate potential strength gain with time.  Jetting techniques were specified for some piles to evaluate this installation technique which could potentially be used during construction.

Traditional axial static load tests were performed on steel HP14x89 and 18in Precast Prestressed Concrete (PPC) square piles.  Rapid (Statnamic) axial load tests were performed on 36 in PCC square piles, 54in PCC cylinder, and 60in steel open-end pipe piles.

A 72in diameter drilled shaft foundation was also installed and tested.  Axial load testing was done using a bi-directional load cell (AFT A-Cell).  Lateral load testing was done using the Statnamic device.

 

Here are some videos of the Statnamic testing, with slow motion action!

 

Foundation contractors that are part of a concessionaire team pursuing the project were allowed to bid the load test program.  Jordan Pile Driving was the successful bidder for the $3.7 million test project.  AFT provided the testing services for the project – dynamic, static, Statnamic, and A-Cell.

A summary of the results can be found in a presentation made to ALDOT at the 62nd Annual Alabama Transportation Conference on February 13, 2019.   (Click HERE to get the presentation). Publication of the results is anticipated to be made in the DFI Journal in the future.

Foundation Testing, Load Testing, Micropiles

DBA and Missouri S&T Conduct Live Load Test at Foothills Bridge as Construction Wraps Up

Just before Christmas, David, Tim, and Nathan joined Dr. Ronaldo Luna and his graduate student, Devin Dixon, of Missouri University of Science and Technology (formerly the University of Missouri–Rolla) to conduct a live load test on the all but officially complete Foothills Parkway Bridge No. 2., near Pigeon Forge, Tennessee.  During installation of the micropile foundations, DBA and Dr. Luna’s research team installed strain gages in four micropiles and at the base of the pier pedestals at both Piers 1 and 2 of the bridge.  Strain data have been collected during construction of the superstructure.  Following completion of the bridge, the live load test involved loading the bridge with four loaded dump trucks at prescribed locations with respect to the instrumented piers.  Data were collected for several load configurations.  The aim of the research is to better understand the performance of micropiles and micropile groups, particularly with respect to bending.

Visiting the site for the load test provided an opportunity to take some great pictures of this particularly scenic bridge nestled in the foothills of the Smoky Mountains.  A new web album of pictures taken by David has been added to our Picasa page here,  and some aerial photos of the nearly completed bridge taken in December by Aerial Innovations have been added to our Picasa web album Foothills Parkway Bridge No. 2 – From a Bird’s Eye View.

DBA News, Drilled Piles, Drilled Shafts, Load Testing

New I-70 Bridge Featured in Foundation Drilling Magazine

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.