DBA recently completed construction observation of pile driving and earthwork for TH-84 across Norway Brook in Pine River, MN. The structure may look like a run of the mill bridge, but the project was replete with geotechnical challenges associated with constructing a new bridge at the toe of an active dam. (We use “run of the mill” with all due affection; there’s no such thing as a boring bridge to DBA.)
During the design phase, DBA designed an instrumentation system and used the resulting piezometric information to calibrate seepage models for the site. The calibrated models were used to analyze conditions during and after construction of the new bridge. DBA also developed an emergency action plan (EAP) that established items to observe during construction, defined levels of distress leading up to all potential failure mechanisms, and designated response actions associated with the distress levels. During construction, DBA was on-site to implement the EAP, coordinating with the contractor, Schroeder Construction, Inc., and MnDOT to quickly respond to any evidence of distress.
Throughout analysis, EAP development, and EAP implementation, DBA collaborated with the bridge designer, Parsons, and MnDOT to identify, explain, and manage the risks associated with this unique and challenging project. We are pleased to see live traffic crossing the dam in the picturesque Minnesota North Country!
Here is a link to a video shot by Dan Ding of DBA during construction:
It’s been a while since we have updated everyone on some of the various publications we have added to our website, so I wanted to provide a few links to some of the newer additions to our Publications tab. One magazine that members of DBA contribute to fairly regularly is Geostrata Magazine. The Geostrata Magazine is a bi-monthly publication of the Geo-Institute. You can join the Geo-Institute and gain access to the magazine by following this link: https://www.geoinstitute.org/publications/geostrata. Dr. Dan Brown published an article in the May-June 2020 edition about lessons learned from failures during pile installation with regards to driving stresses. In the January-February 2021 edition, Dr. Erik Loehr contributed an article about recognizing the inherent value in site characterization. Links for the articles are below.
Dr. Dan Brown has also recently submitted an article to Pile Driver Magazine, which is a bi-monthly publication of the Pile Driving Contractors Association (PDCA). To learn more about the PDCA or become a member, click on logo on the left sidebar. The magazine is free to access and can be found by clicking here while the link for Dr. Brown’s article can be found below.
We have also added a few older papers that David Graham and Paul Axtell have published. One, a case history for a micropile project, was for the International Society of Micropiles. The other was for the 34th annual International Bridge Conference. The links for the papers are found below.
Finally, we have also updated our About Us tab to reflect the change in leadership announced back in April of 2020 and provide an updated view of our current staff here at DBA. The names of each individual are links to their respective resume.
DBA had the great fortune to be working with the Alabama Department of Transportation (ALDOT) on a very interesting bridge project in Lacey’s Spring, Alabama just south of Huntsville, Alabama. On February 12 and 13, 2020 a large landslide occurred on SR-53 (US-231) at milepost 301.7 in Morgan County approximately 1.7 miles south of the Laceys Spring Community. The slide completely severed the 4-lane divided highway which is a major commuting route between Huntsville and several communities south of the city. Many of the workers at the U.S. Army Redstone Arsenal, NASA Marshall Space Flight Center, and the contractors and vendors that support these two major installations live in the communities impacted by the closure of the highway. Detours were established on existing state and county roads, but these added 30 to 60 minutes to commute times, depending on time of day. ALDOT was under significant pressure from the impacted communities to quickly solve the problem and reopen the road.
ALDOT drilling crews were immediately mobilized to the site to begin drilling exploratory borings and install slope inclinometer casings for monitoring slide movements. The Department of Civil Engineering at Auburn University was engaged to perform geophysical testing in conjunction with an existing research project for ALDOT. Geotechnical engineering firm TTL also assisted with field investigation efforts.
DBA and ALDOT immediately began evaluating several alternate concepts for stabilizing the slide and reopening the road during the soil and rock exploratory drilling. The design team looked at several retaining wall options, a complete rebuild of the roadway, and bridges. ALDOT selected a solution that removed most of the existing roadway embankments (built in 1947 and 1970) to reduce loading on the slope and then spanning the slide area with bridges built on the existing road alignments, with the bridges designed to withstand future movements of the slope. Excavation was begun by Reed Contracting before bridge design was complete in order for the rough grading to be done before the bridge contractor mobilized.
The bridges are two-lane structures, one Northbound and one Southbound, each about 947 ft in length. The superstructure is AASHTO BT-72 concrete girders and a concrete deck. There are seven spans in each bridge each about 135ft long. The grading work was begun while the bridge was still being designed to accelerate the schedule and shorten the time the road would be closed.
The foundations for each pier are a pair of 9.5ft diameter, permanently cased drilled shafts with 9ft diameter rock sockets. The sockets are 14ft long into the limestone and shale bedrock. The limestone uniaxial compressive strengths range from 10,820 psi to 28,100 psi.
After much design and analysis in a highly compressed schedule, a bridge contract was let for bid in early May 2020, less than 3 months after the slide occurred. Brasfield & Gorrie was the successful bidder and awarded a $15 million contract that has incentives for finishing early, and disincentives for finishing late.
A.H. Beck (Beck) was the drilled shaft contractor, drilling each shaft, placing reinforcement, and placing concrete. The 9.5ft diameter permanent casing is 5/8 inch wall thickness spiral weld 60ksi steel fabricated by Nucor in Birmingham, Alabama. The shafts are reinforced with a 1.5inch wall thickness, 8ft diameter, 60ksi steel pipe. These pipes were rolled and welded by Favor Steel in Birmingham, Alabama before being trucked to the site. The steel plate was manufactured by SSAB in Axis, Alabama near Mobile. So, the structural steel pipes were completely Alabama-made and the steel travel almost the length of the state!
The pair of shafts for each pier is connected by a reinforced concrete grade beam 10ft wide by 7ft high by 46ft long. To connect the shafts to the grade beam, a 14ft long reinforcement cage is placed in each shaft, embedded 8ft into the shaft with 6ft embedded in the grade beam. The cage consists of 28 No.18 Grade 75 bars.
The project includes a robust instrumentation plan with ShapeArray inclinometers installed in each shaft and in the slope, supplemented by traditional inclinometers in the slope and vibrating piezometers to monitor groundwater levels. DBA and ALDOT will monitor the bridge and slope, intending to be able to measure displacement and calculate strain and loads in the shafts should the slope move again in the future.
Foundations were completed a few days ahead of schedule at the end of July 2020. The deadline to have the bridge open to traffic was early December, 2020, but Brasfield and Gorrie had an aggressive plan to complete the project early and earn the bonus for early completion. The bridge was open to traffic September 28, 2021 to much rejoicing among the commuters and others that use this route. Volkert was the CE&I Consultant on the project for ALDOT, providing construction management and inspection services for the project, ensuring all requirements were met to build the bridges.
To read more in detail about the design and construction of the bridge foundations, we published an article i nthe April 2021 issue of Foundation Drilling Magazine:
I-44 Construction Aerial View; video courtesy of Emery Sapp & Sons
DBA has partnered with bridge designer Parsons and prime contractor Emery Sapp & Sons on a design/build project in Southwest Missouri being administered by MoDOT. Design is complete and the project is in construction phase. The project involves replacing 13 bridges and rehabilitating another six bridges along a 30-mile stretch of I-44 between Sarcoxie and Halltown. The $36 million project is progressing nicely with construction beginning in 2019 and on schedule to be completed by December 15, 2021. To get a birds-eye view of some of the work, check out the video at the top of the post (from Emery Sapp & Sons)
Although smaller bridges than DBA typically works on, challenging subsurface conditions and unique structure types have made things interesting with respect to foundation design and construction. Foundation types for various structures include driven H-piles installed with high-strain dynamic testing, drilled shafts with rock sockets in various rock formations, and spread footings bearing on near surface bedrock where applicable. Pinnacle bedrock surface and karstic foundation conditions are prevalent in the area and this project is no exception. Foundation design had to anticipate the complex subsurface conditions and consider constructability throughout the entire design process.
DBA is excited to announce recent transitions within the company.
Dan Brown, Ph.D., P.E., D.GE, is turning over the reigns of leadership to the next generation in the firm and stepping down as President. While stepping back from day-to-day management of the company, Dan will remain fully involved in technical aspects and client service in the role of Chief Engineer where he will continue to focus on developing practical solutions to complex and challenging foundation issues.
Three Senior Principal Engineers will assume the roles of the officers of DBA. Tim Siegel, P.E., G.E., D.GE has been promoted to Chief Executive Officer. Paul Axtell, P.E., D.GE has been promoted to Chief Operating Officer. Robert Thompson, P.E., D.GE has been promoted to Chief Financial Officer. Tim, Paul, and Robert will provide the management and leadership for the continued growth of DBA and for DBA to provide value to its clients and continue to be a key contributor to the practice of geotechnical engineering.
DBA is happy to announce our two latest additions to the team: Dan Ding, Ph.D., P.E. and Andy Boekmann, Ph.D., P.E. Dan joined us as a Project Engineer in October of 2019 while Andy came on board as a Senior Engineer in February of this year. Read a little bit about both of them below. Go to our About us page to see their resume as well as everyone else on the DBA Team.
Dan Ding, Ph.D., P.E.
Dan received her Ph.D. degree in Civil Engineering from the University of Missouri. Dan specializes in site characterization, geotechnical laboratory testing, Load and Resistance Factor Design, and reliability analysis. Before joining DBA, Dan worked as an adjunct assistant professor at the University of Missouri to teach undergraduate and graduate engineering courses as well as conduct national and state research projects. She also worked as a laboratory geotechnical engineer at Geocomp in Acton, MA for a year after graduation. Dan is based in Columbia, Missouri.
Andy Boeckmann, Ph.D., P.E.
Prior to joining DBA, Andy was a research engineer at the University of Missouri, where he performed research on topics including post-grouted drilled shafts, reliability of geotechnical designs, foundation reuse, and geotechnical asset management. Andy also earned a Ph.D. at the University of Missouri; his dissertation examined the reliability of foundation designs based on site-specific load tests. Andy is the lead author of two NCHRP Synthesis reports, including Current Practices and Guidelines for the Reuse of Bridge Foundations. Prior to working at MU, Andy was a consulting geotechnical engineer for URS Corp. in St. Louis, where he performed design and analysis for large projects, including post-Hurricane Katrina levee design in New Orleans. Andy is an active member of the Deep Foundations Institute, including serving as the vice-chair of the Subsurface Characterization Committee. He is also based in Columbia, Missouri.
The long anticipated update to FHWA GEC 10 Drilled Shafts: Construction Procedures and Design Methods has finally been released by FHWA, The same team that authored the major update in 2010 that shifted design from ASD to LRFD also completed this update: Dr. Dan Brown, P.E., D.GE, and Dr. John Turner, P.E., D.GE of DBA, Dr. Erik Loehr, P.E. of the University of Missouri and DBA, and Mr. Ray Castelli, P.E. of WSP.
This version is an update of the 2010 publication. A complete list of changes made since 2010 is in the opening chapter. Some of the revisions include:
streamlining materials covered in other GEC publications (for example, site investigation and lateral loading) to focus on aspects particular or unique to drilled shafts;
updates to reflect the evolution of construction procedures, tooling, materials, drilling fluids, and concrete placement;
updated design equations for axial loading, particularly for earthquake loading;
Tim Siegel was one of four co-leaders of a Geotechnical Extreme Events Reconnaissance (GEER) team that investigated the impacts of the 2018 Tennessee Earthquake that occurred near Decatur, Tennessee on December 12, 2018. Among the team members were Ali Leib and Mark Madget. The team performed reconnaissance of the area around the epicenter of the quake and prepared a report of their observations.
The quake occurred at 4:14 am EST approximately 12 km north-northeast of Decatur, Tennessee, which is about 240 km southeast of Nashville, TN. The highest recorded peak ground acceleration (PGA) was 0.0215g approximately 36 km from the epicenter. At least 21 aftershocks were recorded through December 18, 2018. The GEER team did not encounter any evidence of earthquake-induced damage in the areas they visited. Organizations such as the Tennessee Valley Authority (TVA), the Oak Ridge National Laboratory (ORNL) , and the Tennessee Department of Transportation (TDOT) “reported that either there was no damage to their facilities or that their operations were unaffected due to earthquake.”
GEER is a “volunteer organization of geotechnical engineers, engineering geologists, and earth scientists from academia, industry, government organizations, and non-profit organizations.” They assemble teams to conduct detailed reconnaissance after extreme events (earthquakes, landslides, floods, hurricanes, etc.) in order “to obtain valuable perishable information that can be used to advance research and improve engineering practice.”
The Beavers is a social and honorary organization organized and managed by members of the heavy construction industry.
The purpose of the Beavers is to promote goodwill, friendliness and consideration within the heavy engineering construction industry; to give recognition to those men and women who have demonstrated particular skill, responsibility and integrity; and to encourage and support entry of promising young individuals into heavy engineering construction.
The Beavers hold two major events annually. The Beavers Awards Dinner is held in mid-January, where individuals are recognized with a Golden Beaver Award for their achievements and contributions to the heavy construction industry in the categories of Management, Supervision, Engineering and Service & Supply.
Dan was honored with the award for his expertise and contributions to the deep foundations industry and its impacts on the heavy construction industry.
Specialists in Deep Foundation Design, Construction, and Testing and Slope Stability Problems