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
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.
Nearly 1,000 project teams submitted their best work to ENR’s regional "Best Projects" competitions. For each of the nine regions, our editors assembled an independent panel of industry judges to home in on the winners in 19 categories. The winners of the regional contests moved on to the national competition. A different set of industry judges examined the projects to distinguish the "Best of the Best" in teamwork, success in overcoming challenges, innovation and quality. This year, a new award honors the safest project, judged by industry safety experts in both the regional and national competitions. Also, ENR’s editorial staff chose one special project as the "Editors’ Choice" to represent the pinnacle of design and construction excellence.
The Audubon Bridge won the Editor’s Choice – the editorial staff’s selection of the “pinnacle of design and construction excellence”. Congratulations to everyone at Audubon Bridge Constructors (Flatiron, Granite and Parsons), Louisiana DOTD, and all who worked on the project!
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.
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:
Representatives with the Society of Civil Engineers, including national president Andrew Herrmann, along with state Transportation Secretary Sherri LeBas are expected to attend. They will place a plaque on the bridge, distinguishing it as one of 250 such historic landmarks around the world. The honor places the Depression-era built bridge in the company of the Eiffel Tower, the Panama Canal, the Hoover Dam and the U.S. Capitol.
The TIMED (Transportation Infrastructure Model for Economic Development) Program is the single largest transportation program in state history. The TIMED Program was created by Act 16 of the 1989 Louisiana Legislature and was voted for by the people. The $5 billion improvement program includes widening 536 miles of state highways to four lanes on 11 project corridors, widening and/or new construction on three major bridges and improvements to both the Port of New Orleans and Louis Armstrong International Airport. The Program is designed to enhance economic development in Louisiana through an investment in transportation projects.
DBA was involved in the test shaft and base grouting program for the drilled shafts supporting the new pier added to supplement the existing piers of the bridge. Check out previous posts here.
Guideline for Interpretation of Nondestructive Integrity Testing of Augered Cast-in-Place and Drilled Displacement Piles
DFI Augered Cast-In-Place Pile Committee (2011-2012) Chaired by Michael Moran
Tracy Brettmann, Principal Author; Bernard Hertlein, Matthew Meyer, Bria Whitmire, Co-Authors
(Image from DFI)
This guideline provides practical guidance for the interpretation of nondestructive testing (NDT) of the integrity of augered cast-in-place (ACIP) and drilled displacement (DD) piles. … This guideline supplements DFI’s two primary publications on ACIP piles: Augered Cast-in-Place Pile Manual (2003) and the Inspector’s Guide for Augered Cast-in-Place Piles (2010). This guideline was developed to provide 1) more detailed explanations of the various test methods available, 2) guidance on interpretation of the results, and 3) some typical examples of the data and interpretation.
Seismic and Lateral Load Design and Testing Guidelines
DFI Seismic and Lateral Loads Committee (2011-2012)
Chaired by Mark Petersen and Zia Zafir (2003-2009)
Robert Kruger, Guideline Editor
This guidance document is intended to assist geotechnical engineers, pile designers, and contractors in analysis, design, and testing of piles and drilled shafts for lateral loads. … … This document discusses the background of different analytical and testing procedures and presents the recommended methods for analysis, design and testing of piles for lateral loads.
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/DFIDrilled 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.
Later 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.