Tag Archives: Drilled Shaft Design

Bridge Construction, Bridge Foundations, Drilled Shafts, Foundation Design, Instrumentation, Miscellaneous, Slope Stability

Instrumentation at US 231 bridge and Slide

(Written by Andy Boeckmann – DBA)

After successful design and construction of the US 231 emergency slide repair in Lacey’s Spring, Alabama, DBA shifted gears to install a state-of-the-art monitoring system for the project. The monitoring system allows DBA and ALDOT to remotely detect any movement of the drilled shafts, changes in groundwater levels, and movement of the slope, itself.

The monitoring system includes ShapeAccelArray (SAAV) devices to measure displacement profiles with depth. SAAVs, which are manufactured by Measurand, consist of a chain of rigid segments, each 1.5-ft long and about 1-inch diameter. DBA installed 27 SAAV devices at US 231. Each of the 24 drilled shafts has one SAAV, which DBA installed in a 1-inch conduit welded to the drilled shaft reinforcement and emerging from the top of the grade beams connecting the shafts. The other three SAAVs are “free-field” SAAVs, installed in the soil between bridge bents. DBA worked with ALDOT’s drill crews to install the free-field SAAVs.

ALODT drill crew installing a free-field SAAV under the Northbound bridge.

 

Completed free-field and foundation instruments at Bent NB4.

 

DBA also worked with the ALDOT drill crews to install vibrating wire piezometer devices at six locations across the site. Each location includes two piezometers, one in the soil and one just below the top of rock. The piezometers were installed using the fully-grouted method. The piezometers measure pore pressure, which DBA uses to interpret groundwater conditions at the site.

 

Datalogger atop a vibrating wire piezometer.

 

All of the instruments are connected wirelessly to two central hubs that collect the data. The hubs are solar powered.  One of the hubs is equipped with a cellular modem that facilitates remote collection of the data.  RST Instruments manufactures the monitoring equipment as well as the vibrating wire piezometers.

Housing for SAAV devices installed in drilled shafts.

 

R-star hub and solar panel mounted to SB Bent 6.

 

Inside of data collection hub.

 

Results of the monitoring program indicate the foundation system is performing as designed. The US 231 structure has passed its first wet season with flying colors. Despite several periods of heavy rain that resulted in localized slope movement, the drilled shafts have shown only very small movement, typically less than 0.05 inch. The movement shown in the shafts indicates they are resisting loading from the slope movement, but with plenty of reserve capacity. The monitoring system has successfully captured realistic results from all instruments, including the drilled shaft and free-field SAAVs and piezometers.

Piezometer data shows strong correlation between rainfall and increases in groundwater levels.
Example of SAAV drilled shaft displacement. Shaft displacements are very small, typically less than the stated accuracy of the SAAV devices.

The monitoring system is more than just bells and whistles: it is an integral part of DBA’s design philosophy for the US 231 project. DBA engineers were able to implement the innovative strategy of drilled shafts through an active landslide because we knew performance of the foundation system would be actively monitored. This strategy represents a modern take on the observational method, which has represented best geotechnical engineering practice since the profession originated. DBA will also use results of the monitoring program to inform future designs, consistent with our commitment to using state of the art to improve the state of practice.

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:

Thompson, W.R. and Dapp, S.D. (2021). “Innovative Landslide Solution”, Foundation Drilling, Vol XLII, No. 3April 2021, pp51-62.

Bridge Construction, Bridge Foundations, Drilled Shafts, Foundation Design, Slope Stability

US 231 Emergency Slide Repair – Laceys Spring, Alabama

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 drill rigs performing exploratory drilling (DBA)

 

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. 

 

ALDOT UAV flight June 16, 2020

ALDOT UAV flight July 07, 2020

ALDOT UAV flight July 23, 2020

ALDOT UAV flight July 28, 2020

ALDOT UAV Flight Aug 08, 2020

ALDOT UAV Flight Sep 2, 2020

ALDOT UAV Flight Sep 15, 2020

 

Excavating first shaft on the site (DBA)

 

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!

8ft diameter x 1.5in wall steel pipe for shaft reinforcement (DBA)

 

Inner structural pipe (1.5in) and outer casing (5/8in) (DBA)

 

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.

Grade beam at NB Bent 7 with column steel (DBA)

 

Completed shaft with reinforcing cage to embed in grade beam (DBA)

 

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:

Thompson, W.R. and Dapp, S.D. (2021). “Innovative Landslide Solution”, Foundation Drilling, Vol XLII, No. 3April 2021, pp51-62.

Click HERE for some of the photos DBA team members have taken during construction.

To see aerial views from ALDOT’s UAV flight taken on July 10, 2020, click HERE.

 

 

Bridge Foundations, Drilled Shafts, Foundation Design, Foundation Testing, Load Testing

FHWA GEC 10 Update for 2018 Released!

UPDATE!  Posting of the PDF to the FHWA Resource page has been delayed while the formatting issues noted below are worked out. 

CLICK HERE for a Final DRAFT for use until FINAL document is posted by FHWA.

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;
  • updated group design to reflect recent changes to AASHTO design guidelines;
  • updates on integrity testing (including use of Thermal Integrity Profiling, or TIP); and,
  • an outline for a process for assessment and acceptance of drilled shafts based on inspection records and integrity tests.

You can download the new PDF here.  The PDF posted is “preliminary” with some minor formatting and other items to be cleaned up by the fall.

Bridge Construction, Bridge Foundations, Foundation Design

Goethals Bridge Replacement – Webcam!

goethals-replacement-logo

DBA is on the design-build team that is replacing the Goethals Bridge for the Port Authority of New York and New Jersey (PANYNJ). We are not able to post much about the project or our involvement due to security agreements. However, the PANYNJ has a public website for the project (http://www.panynj.gov/bridges-tunnels/goethals-bridge-replacement.html) that has several webcams.  As is the case with most big projects these days, the webcams are a common feature and show some great views of the project.

To give you an idea of what the project involves, here is a summary from the PANYNJ site:

The replacement bridge will be located directly south of the existing bridge and will provide:

  • Three 12-foot-wide lanes in each direction replacing the current two narrow 10-foot-wide lanes
  • A 12-foot-wide outer shoulder and a 5-foot-wide inner shoulder in each direction
  • A 10-foot-wide sidewalk/bikeway along the northern edge of the New Jersey-bound roadway
  • Improved safety conditions and performance reliability by meeting current geometric design, structural integrity, security and seismic standards, and reduces life-cycle cost
  • A central corridor between the eastbound and westbound roadway decks, sufficient to accommodate potential transit service
  • State-of-the-art smart bridge technology

The project also includes the demolition of the existing bridge upon completion of the replacement bridge.

You can learn more about the project at the same web site.  There is also a site for the current bridge, including history of the construction, etc.

Bridge Construction, Bridge Foundations, Drilled Shafts, Foundation Design

Drilled Shafts Complete at St Croix

Pier 9 FootingAs reported by the Minneapolis Star Tribune, Case Foundation recently finished constructing 40 drilled shafts at the St Croix River Crossing Project.  Since early June, Case has been working at a feverish pace to construct the drilled shaft foundations for the new extradosed bridge between Minnesota and Wisconsin.  As of November 8th, all of the drilled shafts are officially complete.  General contractor Kramer is working to finish the pier footings and support tower bases by early 2014.  Soon, the joint venture of Lunda and Ames will begin construction of the $380 million bridge superstructure.

As MnDOT’s foundation consultant for the project, DBA has been on site during much of the foundation construction over the past five months.  Some pictures taken during this time, along with several pictures from MnDOT are available for viewing on our Picasa Page.  More pictures and information can be found on the project website and Facebook Page, and the project can be viewed live via webcam.  Previous DBA blog posts about the main project and the predesign load test program can be found here.

DBA is pleased to wrap up its role on the St Croix Crossing Project with a very positive outlook.  The drilled shaft construction proceeded on schedule and as planned without unexpected challenges, and our strong client relationships with MnDOT continued to grow stronger.  It was also nice to see familar faces from Case, Braun Intertec, and Parsons Transportation Group, many of whom we worked with us at Hastings.  We very much look forward to working with these partners again in the future!

Bridge Construction, Bridge Foundations

Missouri Bridge Project Updates–Hurricane Deck and MRB

Time for a quick update on two projects owned by MoDOT on which DBA was involved.

First, the official opening of the Missouri Route 5 – Hurricane Deck Bridge Replacement was held on September 7th.

Hurricane Deck

History was made on Sept. 7, 2013when state and local officials cut the ribbon on the new Hurricane Deck Bridge during a ceremony held in the center of the new structure.  The bridge officially opened to traffic in the late evening on Monday, Sept. 9. The original bridge is now closed and will be prepared for demolition during the remainder of 2013. Final demolition will take place in the spring of 2014.

Check out this time lapse video of the bridge being built.

 

Last, the new Mississippi River Bridge in St. Louis.

Clipboard01

They have closed the gap on the bridge – lots of neat photos here showing the final deck panels in place.  Here they are placing the final edge girders.  Finally, here is a link to the live construction cameras.

Bridge Foundations, Drilled Shafts, Driven Piles, Foundation Design, Foundation Testing, Load Testing

DBA Engineers Coauthor Cover Story of Latest DFI Magazine

https://danbrownandassociates.com/wp-content/uploads/2013/08/DFI-Cover-July-Aug-2013_small.jpg

Cover Image of the Hastings Mississippi River Arch Bridge

The featured article in the July/August 2013 issue of Deep Foundations, the magazine of the Deep Foundations Institute, is coauthored by Dan, Paul, and Rich Lamb, P.E., of the Minnesota Department of Transportation (MnDOT).  The article summarizes how load testing has been used successfully as part of the foundation design process by DBA and MnDOT on five major bridge projects along the Mississippi and St. Croix Rivers during the last 10 years and the lessons learned from these successive projects.   The featured bridge projects include two major design-build projects, the emergency replacement of the I-35W St. Anthony Falls Bridge (2007) and the Hastings Mississippi River Arch Bridge (2011).  The other traditional design-bid-build projects include the I-494 Wakota Mississippi River Bridge, the U.S. Hwy 52 Lafayette Mississippi River Bridge, and the St Croix River Bridge.  As is often the case, each of these projects presented unique geological and hydrogeological challenges to foundation design – despite the projects all being within 30 miles of each other – including thick layers of highly organic compressible soils overlying bedrock, layers of cobbles and boulders, artesian groundwater conditions, and bedrock ranging from weak weathered sandstone to very hard dolostone.  These varying conditions resulted in the use and testing of a variety of foundations.  Load testing “with a purpose” has proven to be an integral part of the design and construction process on these projects, as the load tests were not simply for verification of a design but provided valuable information used to optimize the designs and provide quality assurance of the construction practices.

Please read the full article here or in a copy of Deep Foundations, a bi-monthly magazine published by the Deep Foundations Institute.   DFI is an international technical association of firms and individuals involved in the deep foundations and related industry.  More information about DFI and how to become a member can be found at www.dfi.org.

Also see our Projects Page for more about some of these projects and our other major projects.

Drilled Shafts, Foundation Design

Calibration of Resistance Factors for Drilled Shafts -A report from the LADOTD

Note: Okay – I’ll admit – I also do a blog for the Geo-Institute Deep Foundations Committee.  as such, there are often things that I feel should be posted at both – to get the widest possible audience! So, if you have already been over there, this post will look very familiar.  It is much easier to reuse a post written by yourself. – Robert

With the adoption of LRFD design methods by the American Association of State Highway and Transportation Officials (AASHTO), the Federal Highway Administration (FHWA), and most state Departments of Transportation,  the big question in the geotechnical world is “What resistance factor should we use for __________?”.  AASHTO LRFD Bridge Design Specifications provide a lot of guidance, but many in the industry are working to calibrate resistance factors to regional or local design methods and soil conditions. Various universities and state DOTs, with assistance from FHWA, National Highway Institute (NHI), and the Transportation Research Board (TRB) are conducting research projects to provide some answers to the big question (there is never just one answer in geotechnical engineering!).

Randy Post over at GeoPrac.net recently blogged about a newly released report from The Louisiana Transportation Research Center and the Louisiana Department of Transportation and Development (LADOTD) on their investigation for calibrating resistance factors for the design of axially loaded drilled shafts.  From the report abstract:

As a continuing effort to implement the LRFD design methodology for deep foundations in Louisiana, this report will present the reliability-based analyses for the calibration of the resistance factor for LRFD design of axially loaded drilled shafts using Brown et al. method (2010 FHWA design method). Twenty-six drilled shaft tests collected from previous research (LTRC Final Report 449) and eight new drilled shaft tests were selected for statistical reliability analysis; the predictions of total, side, and tip resistance versus settlement behavior of drilled shafts were established from soil borings using both 1999 FHWA design method (O’Neill and Reese method) and 2010 FHWA design method (Brown et al. method). The measured drilled shaft axial nominal resistance was determined from either the Osterberg cell (O-cell) test or the conventional top-down static load test.

You can download a PDF of the report here.

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

DBA Wraps Up Load Test Program and Proceeds with Design on St. Croix Bridge

Project rendering courtesy of HDR 

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.

For more information, please see:

The MnDOT Project Page

The DBA Project Summary Sheet

DBA News

Barry Meyer, P.E. joins DBA!

12_Barry MeyerWe are pleased to announce that Barry J. Meyer, P.E., has joined DBA. Barry is a recognized expert in the design and construction of deep foundations. His over 30 years of geotechnical engineering experience includes time at McClelland Engineers in Houston where he designed large diameter high capacity driven piles for major offshore structures and developed subsea geotechnical instrumentation. He applied that knowledge at Marathon Oil Company where he was part of the team that installed the Steelhead oil production platform in Cook Inlet, Alaska.

After his time in Texas, Barry spent time at both Leighton and Associates and at Law Engineering in California, before joining HDR in their Tampa, Florida office. During this time, his drilled shaft experience includes the H-3 Windward Viaduct on Oahu, Hawaii where drilled shafts were used for the first time to support a major bridge structure and are now the foundation of choice in Hawaii. He was also innovative in the use of the Osterberg O-Cell as part of the repair of the Los Angeles Coliseum after the devastating Northridge earthquake.

Barry has worked on numerous international projects in a variety of capacities including the Confederate Bridge connecting New Brunswick to Prince Edward Island over the ice filled Northumberland Straits; the 55 km elevated Bang Na Expressway Project in Bangkok, Thailand; and the Puente de la Unidad cable-stayed bridge over the Santa Catarina River, Monterey, Mexico. He also has considerable seismic engineering experience, and has designed and constructed flood protection levee systems and water storage reservoirs.

Barry will be based in the Tampa, Florida area. You can check out more details about him on the About Us page of our blog.  Welcome, Barry!