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.
Here is a blast from the past on pile groups: NCHRP Report 461 – Static and Dynamic Lateral Loading of Pile Groups. I had a request for this report recently, so I found it and figured we needed to post the links to it. Dan was the lead researcher on this report during his time at Auburn University, and had an all-star line up that included Dr. Mike O’Neill and Dr. Mike McVay, two of the heavy hitters in foundation engineering. The report introduction gives a good summary of the contents:
A key concern of bridge engineers is the design and performance of pile group foundations under lateral loading events,
such as ship or ice impacts and earthquakes. This report documents a research program in which the following were developed:
(1) a numerical model to simulate static and dynamic lateral loading of pile groups, including structural and soil hysteresis and energy dissipation through radiation; (2) an analytical soil model for nonlinear unit soil response against piles (i.e., p-y curves) for dynamic loading and simple factors (i.e., p-multipliers) to permit their use in modeling groups of piles; (3) experimental data obtained through static and dynamic testing of large-scale pile groups in various soil profiles; and (4) preliminary recommendations for expressions for p-y curves, damping factors, and p-multipliers for analysis of laterally loaded pile groups for design purposes. The report also describes experimental equipment for performing site-specific, static, and dynamic lateral load tests on pile groups.
Several full-scale field tests were conducted on pile groups of 6 to 12 piles, both bored and driven, in relatively soft cohesive and cohesionless soils. All of the groups were loaded laterally statically to relatively large deflections, and groups of instrumented pipe piles were also loaded dynamically to large deflections, equivalent to deflections that might be suffered in major ship impact and seismic events. Dynamic loading was provided by a series of impulses of increasing magnitude using a horizontally mounted Statnamic device.
For a relatively short (50 pages) report, there is a lot of information packed into it gleaned from a lot of full-scale field work.
Lateral Statnamic test, picture by David Graham of DBA, click here for a YouTube video
DBA has been selected by MnDOT as a geotechnical and load testing consultant for the design phase load test program and foundation design of a new bridge crossing the the St. Croix River near Oak Park Heights and Stillwater, Minnesota. The new bridge will carry State Highway 36 across the St. Croix River between Minnesota and Wisconsin. Currently, Highway 36 is carried on an 80-year old two-lane vertical lift bridge in downtown Stillwater. The new bridge will divert the heavy through traffic away from the historic downtown center and reduce travel time for commuters. The iconic lift bridge will be converted to a pedestrian and bicycle only structure.
Work began this summer on the load test program which consisted of one 8-foot test shaft, two 24-inch driven steel pipe piles, and two 42-inch driven steel pipe piles, all installed in the St. Croix River along the alignment of the new bridge. Local contractor Carl Bolander & Sons Co. was selected as the general contractor for the load testing program. Bolander self-performed the installation of the test piles and sub-contracted the construction of the test shaft to Case Foundation Company, of Chicago, Illinois. Axial load testing of the test shaft was performed by Loadtest, Inc., of Gainesville, Florida, using Osterberg Cells (O-cells). Dynamic testing of the driven piles using the pile driving analyzer (PDA) was performed by local geotechnical consultant Braun Intertec. Axial testing of the driven piles and lateral testing of the shaft and one of each size pile was performed using the Statnamic Device by Applied Foundation Testing, Inc. (AFT), of Jacksonville, Florida. DBA provided pre-test recommendations, assisted MnDOT in construction oversight, provided analysis and review of the test results, and made design recommendations based on the test results.
Following the successful load test program, DBA is working with MnDOT’s structural design consultants for the project, HDR, Inc. and Buckland & Taylor Ltd. to optimize the bridge design. Already, the design team has been able to lengthen the bridge spans and eliminate a river pier as a result of the load test results, as was recently reported by Minnesota Public Radio (MPR). Also, because the total number of drilled shafts required to support the main pier towers has been reduced, construction on the foundations will been moved up to 2013 rather than the original estimated start date in 2014, also reported by MPR.
A major construction feat was recently completed at the Highway 61 bridge project in Hastings, Minnesota when the 545-foot, 6.5 million-pound main bridge span was hoisted into place, 50 feet above the Mississippi river. The main span, the longest free-standing tied-arch in North America, was constructed on the shore of the Mississippi River, about a mile upstream of the river crossing. Placed on massive dollies, the span was rolled onto a set of six barges and floated downstream. Once positioned under the piers, hydraulic jacks on top of the piers slowly lifted the span into place. Around midnight on Sunday, September 23rd, 2012, the lift was complete. By noon of the following day the span was secured in place and the existing bridge was reopened to traffic. A time lapse video of the entire process can be viewed below or on YouTube.
Links to news stories published about the main span lift:
Some new pictures of the Hastings bridge project in Hastings, Minnesota have been added to our Picasa Web Album: Hastings Bridge Construction. The pictures were taken by myself, David Graham, who has been in the area working on a load test program for a new bridge crossing the St. Croix River near Stillwater, Minnesota, and Griff Wigley, our blog coach who lives nearby in Northfield, Minnesota. The pictures show some of the recently poured deck sections, the completed piers, and the main span arch construction. Once completed, the main span arch will be moved onto barges, floated downstream, and lifted into place in one piece. We have chronicled this interesting and successful project in several previous blog posts that can be found here.
DBA is proud to announce the addition of Nathan Glinski, E.I. to our staff. Nathan is a recent graduate of the Georgia Institute of Technology (like Dan and Tim! Go Jackets!). Nathan completed his M.S. in civil engineering at Georgia Tech where he also did his undergraduate work. While at Georgia Tech, Nathan was a research assistant under the supervision of Dr. David Frost, P.E. where he investigated the use of pile foundations as geothermal heat exchangers. In addition to his research, Nathan was a teaching assistant for an undergraduate geotechnical engineering course, gaining experience in a wide variety of laboratory soil tests as well as managing the grading of reports and homework for 100 undergraduate students. Nathan has been the resident summer intern for DBA since 2010 and will now be joining us full time as a staff project engineer.
On a more personal note, Nathan is also an accomplished trials motorcycle rider, having been riding since a youth. He has often ridden the courses and trails at the Trials Training Center (owned by Dan and co-located at DBA World HQ). He is a big volunteer/instructor/participant in events at the TTC, as seen in two posts last year here (helmet cam while riding a course), and here (instructor).
As you can see from his photo, he has adopted the official hairstyle of DBA. Coincidentally, being comfortable in a hard hat also means comfort when wearing your trials helmet!
Massive prestressed concrete girders, some of them setting a record for the longest concrete girders used on a Minnesota bridge, have been set at the New Hastings Bridge, currently under construction in Hastings, Minnesota. The largest girders are 174 feet long, 8 feet tall, and weigh 108 tons! There is a video of one of these huge beams being delivered on a 16 axle truck, below. An article from the December 2011 issue of Concrete Products magazine about the girders can be found here. To date, all of the girders between the north abutment and main span have been placed. Crews are preparing piers 5 and 6 for the main span steel arches, which are scheduled to be floated in by barge and lifted into place late this year. MnDOT has two web cams where the bridge construction and the arch construction can be viewed. The Minneapolis Star Tribune has also been following the construction. Their latest article, which hails the bridge as “a monumental marvel,” can be found here.
The drilled shaft foundations for the new I-70 Mississippi River Bridge in St. Louis, MO are the subject of two recent papers written by Paul and Dan and published by DFI. Dan presented the paper focusing on the Alternate Technical Concept (ATC) process at the DFI 36th Annual Conference in October. (previous post here). A case history paper by Paul and Dan was published last month in Volume 5, Number 2 of the DFI Journal. Links to the papers are below, as well as on our Publications page. Other posts on this bridge are here.
This paper was originally published in the Proceedings of the 36th Annual Conference on Deep Foundations, the 2011 annual meeting of DFI. Go to www.dfi.org to purchase the procedings or for further information.
This paper was originally published in DFI’s bi-annual journal, Volume 5, No. 2 in December 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.
DBA is pleased to announce that Dr. D. Michael Holloway, P.E. has joined the DBA team. Mike is a recognized expert in driven pile foundation design and dynamic testing, in-situ testing, instrumentation, and earthquake engineering. His over 40 years of foundation and geotechnical engineering experience includes stints at the U.S. Army Corps of Engineers Waterways Experiment Station (WES) in Vicksburg, MS, and Woodward-Clyde Consultants in Oakland, CA. He founded InSituTech, which specialized in engineering deep foundations and applying insitu soil testing services.
When starting InSituTech, Mike broadened the professional practice beyond “conventional” PDA-related testing and analyses services. Rather than just test and report to satisfy QC requirements during construction, he applied dynamic testing and analyses to enhance foundation design and constructability, as well as to improve on-site troubleshooting of construction problems. The efforts paid off as the firm made significant changes in the way PDA services became integrated into the design/build process on several major marine facilities and bridge projects in the west and in the Pacific.
Mike is a Blue Devil, having earned his B.S., M.S., and Ph.D. at Duke University in North Carolina. Raised in New York, he made his way to California seeking engineering gold soon after his time at WES. He has been based there ever since.
Mike’s presence in California makes DBA a practically coast-to-coast firm (well, at least East Tennessee to California). We at DBA are excited at the expertise Mike adds to our portfolio and look forward to his contributions to the team. Welcome, Mike!
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.