Category Archives: Load Testing

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.

“Geotechnical Monument” in St. Louis

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It may not have been intended as such, but we will “claim” this large rock core on the Mississippi River as a “geotechnical monument”.  At the site of the new I-70 crossing over the Mississippi River in St. Louis, one of the 11-foot diameter limestone rock cores retrieved from one of the rock sockets drilled for the bridge foundations has been placed on the river bank along with a sign. Our own David Graham stopped by and had some pictures taken when on a personal trip their last year.  So, the next time you are in St. Louis, look for the big hunk of rock on the west bank (St. Louis side) near the new bridge north of the Arch.

Check out our previous posts on this project here.

 

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NCHRP Report 461–Static and Dynamic Lateral Loading of Pile Groups

nchrp_rpt_461-Static and Dynamic Loading of Pile Groups

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.

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

Busy Fall Speaking Schedule for DBA

The months of September and October will be busy for several DBA team members speaking at a variety of conferences and events. Dan Brown and John Turner will be speaking at the ADSC/DFI Drilled Shaft Seminar and Field Day in Denver September 12 and 13. Dan will be giving the 4th Annual Osterberg Memorial Lecture at the DFI Educational Trust dinner being held on the evening of the 12th. Dan and John will be speaking mostly on construction issues during the seminar.   

 

MWGC logoLater in the month, Dan and Robert Thompson are both featured at the 2012 Midwest Geotechnical Conference hosted by Ohio DOT in Columbus, Ohio. Dan will be speaking on base grouted shafts while Robert will give his presentation on the ADSC SE Chapter rock socket load test research program.     

 

STGEC 2012In October, Dan and Robert appear together again at the 2012 Southeastern Transportation Geotechnical Engineering Conference (STGEC) in Richmond, Virginia. This will be the 43rd installment of this conference, hosted this year by the Virginia DOT. Dan will speak on design-build construction issues for deep foundations, while Robert will again present the load test research project. Dan will also speak at the 26th Central Pennsylvania Geotechnical Conference in Hershey, Pennsylvania in October, and Robert will speak at the ADSC Carolinas Chapter meeting in Greenville, NC.

Mike Holloway SuperPile 2012 Presentation

DSCN2543We have added Mike Holloway’s presentation at DFI SuperPile 2012 on May 17, 2012 to our Presentations Page.  Mike discussed some of the issues related to pile testing and what can influence the blow counts that are often relied upon to accept piles.  He covered the types of testing, limitations of various methods, and issues to consider when applying test results to production piling.

A Driven Pile is a Tested Pile – Not So Fast! – D. Michael Holloway, Ph.D., P.E. – DFI SuperPile 2012, Portland, OR, May 17, 2012

Early Statnamic Lateral Load Test Paper by Dan

While at the 2012 Geo-Congress I purchased a couple of books at the ASCE bookstore.  One was GSP 88: Analysis, Design, Construction and Testing of Deep Foundations, Proceedings of the OTRC ‘99 Conference. There are several interesting papers in the GSP, including an early paper by Dan on lateral Statnamic testing.  A full scale lateral load test was performed on a 36 inch tests shaft using a Statnamic device.  The test was performed at the Auburn University National Geotechnical Experiment Station Site (NGES).  I guess you could say this paper is literally a “blast” from the past!

 

Brown, D.A. (1999). “An Experiment with Statnamic Lateral Loading of a Drilled Shaft”, Geotechnical Special Publication No. 88: Analysis, Design, Construction and Testing of Deep Foundations, Proceedings of the OTRC ‘99 Conference, Austin, Texas, April 29-30, 1999, ASCE, pp309-318.

Hyperbolic P-Y Model from Lateral Load Tests in Loess Soils

Another paper featured in the December 2011 issue of the DFI Journal was authored by Steve and Dan, along with Dr. Bob Parsons at the University of Kansas

Dapp, S.D., Brown, D.A., and Parsons, R.L. (2011). “Hyperbolic P-Y Model for Static and Cyclic Lateral Loading Derived from Full-Scale Lateral Load Tesing in Cemented Loess Soils”, DFI Journal Volume 5, Number 2, December 2011, Deep Foundations Institute, pp35-43.

The paper describes a program of lateral load tests on six drilled shafts installed in a loess deposit at a site in Wyandotte County, Kansas.  The lateral load test data, along with site characterization data that included CPT data, were used to develop a hyperbolic model to generate p-y curves for use in lateral load analyses in cemented soils.  The model should be applicable to many “c-phi” soils (soils with both a cohesion intercept and a friction angle, such as cemented soils).  Degradation of the static soil model to account for cyclic loading effects is included in the new model.

This paper was originally published in the DFI Journal, Vol. 5 No. 2, December 2011, the bi-annual Journal of the Deep Foundations Institute.  DFI is an international technical association of firms and individuals involved in the deep foundations and related industry. The DFI Journal is provided to DFI members at no cost electronically or can be purchased in print at www.dfi.org.

This paper is one of several papers and articles published form a series of research projects by KU and the Kansas DOT.  Some of the previous work can be found at these links:

Characterization of Loess for Deep Foundations (1/26/10)

Pierson, M., Parsons, R.L., Han, J., Brown, D.A. and Thompson, W.R. (2008). "Capacity of Laterally Loaded Shafts Constructed Behind the Face of a Mechanically Stabilized Earth Block Wall", Report for the Kansas Department of Transportation

Lateral load tests of drilled shafts behind an MSE wall – research with KDOT and KU (12/6/07)

ADSC SE Chapter Lawrenceville Test Site Report Published

Fig 12 - Test shaft 1 completedThe report for the ADSC Southeast Chapter Lawrenceville, Georgia Test Site is complete and published (link below).

This is the second report from their research project on rock-socketed drilled shafts in the Southeast U.S.  This report is from the Lawrenceville, Georgia test site where shafts constructed in metamorphic rock of the Piedmont geologic province were load tested using the O-Cell load test device.  The report link is below.  Additional information about the test site can be found at the Lawrenceville Site Page.

The first site of this project was in Nashville, Tennessee where shafts constructed in limestone were tested.  Information on the Nashville Site and the test reports can be found at the Nashville Site Page.

Both reports will be the feature of a paper and presentation by Robert at the 2012 ADSC Expo, March 13-17, in San Antonio, TX. More information about the Expo can be found here.

Thompson, W.R., Brown, D.A., and Hudson, A.B. (2012). “Load Testing of Drilled Shaft Foundations in Piedmont Rock, Lawrenceville, GA, Report for ADSC Southeast Chapter, January, 2012.

ADSC Lawrenceville Test Site–We Have Winners!

That’s right load test fans, The results are in! The ADSC Southeast Chapter is proud to announce the “winners” from the prediction contest for the Lawrenceville, GA test site. In the table below, we have listed the winner and their prediction. The winners are the closest to the average measured values as reported by Loadtest, Inc and may not represent the reported maximum values recommended in the final report by DBA. We won’t release the final report until the ASCE Georgia Section Geotechnical Group meeting November 15, 2011 at 6:30pm at the Georgia Power Company’s Headquarters in Atlanta. Dr. Brown will be presenting the findings then – so come to the meeting and get it first, or look to the DBA or ADSC web sites after November 15th to get the report.

 

Shaft

Name

Prediction

1 – Unit Base Resistance

Gloria Rodgers
(Building and Earth Sciences, Inc.)

750 ksf

1 – Unit Side Resistance

Todd Barber (Geo-Hydro Engineers, Inc.)

50 ksf

2 – Unit Base Resistance

Todd Barber (Geo-Hydro Engineers, Inc.)

690 ksf

2 – Unit Side Resistance

TIE:
Jim Pegues (Southern Company Svcs.)
Tom Scruggs (Georgia DOT)

3 ksf