Tag Archives: TRB

NCHRP Synthesis 478 – Design and Load Testing of Large Diameter Open-Ended Driven Piles

nchrp_syn_478_Design and Load Testing of Large Diameter Open-Ended Driven Piles_2015

The Transportation Research Board (TRB) has released a synthesis report prepared by Dan and Robert on large diameter piles: NCHRP Synthesis 478, Design and Load Testing of Large Diameter Open-Ended Driven Piles.  The report is a summary of the state of practice with regard to Large Diameter Open-Ended Piles (LDOEPs) in the transportation industry.  We conducted a survey of state DOTs as well as interviews with private practitioners to summarize current practices as well as recommend best practices with regard to the selection, design, installation, and testing of LDOEPs.   Several state DOTs are using LDOEPs more regularly where large foundation loads may exist and/or the piles are subject to significant unsupported length due to scour, liquefaction, or very weak surficial soils. Marine construction conditions also favor the use of these piles, particularly where pile bents might be employed to eliminate footings.

You can download a PDF of the report or purchase a hard copy at the link below.

Brown, D.A. and Thompson, W.R. (2015). NCHRP Synthesis 478, Design and Load Testing of Large Diameter Open-Ended Driven Piles, Transportation Research Board, National Academies, Washington, D.C.

NCHRP Report 697 – Design Guidelines for Increasing Lateral Resistance of Bridge Pile Foundations

nchrp_rpt_697_coverWe have added a link to the NCHRP Report No. 697 Design Guidelines for Increasing Lateral Resistance of Bridge Pile Foundations.  This report was published in 2011 and authored by Kyle Rollins, Pd.D., P.E. of Brigham Young University and our own Dan Brown.  Dr. Rollins is a Professor in Geotechnical Engineering specializing in earthquake engineering and soil improvement.

 

In the forward of the report, Andrew Lemer of TRB writes:

NCHRP Report 697: Design Guidelines for Increasing the Lateral Resistance of Highway- Bridge Pile Foundations by Improving Weak Soils presents design guidance for strengthening of soils to resist lateral forces on bridge pile foundations. Lateral loads may be produced by wave action, wind, seismic events, ship impact, or traffic. Strengthening of soil surrounding the upper portions of piles and pile groups—for example by compaction, replacement of native soil with granular material, or mixing of cement with soil—may be more cost-effective than driving additional piles and extending pile caps as ways to increase the bridge foundation’s capacity to resist lateral forces associated with these loads. This report presents computational methods for assessing soil-strengthening options using finite-element analysis of single piles and pile groups and a simplified approach employing commercially available software. The analysis methodology and design guidelines will be helpful to designers responsible for bridge foundations likely to be exposed to significant lateral loads.

Be sure to browse all of the nifty reports and projects in geotechnical and foundation engineering at TRB here.

Also check out our Publications page regularly for new postings.

Geofoam and Slope Stability

A recent TRB E-newsletter (4/2/2013) was spotlighted by Randy Post (aka RockMan) at Geoprac.net.  The newsletter was about the publication in January of Research Results Digest 380: Guidelines for Geofoam Applications in Slope Stability Projects.

TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 380: Guidelines for Geofoam Applications in Slope Stability Projects explores the use of expanded polystyrene-block geofoam for slope stabilization projects. For the purpose of the report, slope stabilization projects include new roadways as well as repair of existing roadways that have been damaged by slope instability or slope movement.

The research was performed by the Department of Civil Engineering at The University of Memphis (UoM). David Arellano, Associate Professor of Civil Engineering at UoM, was the Project Director. The other project investigators were Timothy D. Stark, Professor and Consulting Engineer, Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign; John S. Horvath, Consulting Engineer and Professor, Civil and Environmental Engineering Department at Manhattan College; and Dov Leshchinsky, President of ADAMA Engineering, Inc., and Professor, Department of Civil and Environmental Engineering at the University of Delaware.

The digest is a summary of the NCHRP Project 24-11(02), “Guidelines for Geofoam Applications in Slope Stability Projects.”

This report presents the results of a study performed to develop a comprehensive document that provides both state-of-the-art knowledge and state-of-practice design guidance to facilitate the use of EPS-block geofoam for slope stabilization and repair. This report includes the following five primary research products: (1) summary of relevant engineering properties, (2) a comprehensive design guideline, (3) a material and construction standard, (4) economic data, and (5) a detailed numerical design example.

The project was initiated to develop comprehensive design guidelines for use of geofoam in slope stability applications.  According to the Digest, geofoam use is becoming more widespread in the U.S., but the adoption of it as a routine roadway construction material has been slowed by lack of design guidelines.

Although EPS-block geofoam for road construction is an established technology and despite the more than 30 years of extensive and continuing worldwide use of EPS-block geofoam, it has been underutilized in U.S. practice because a comprehensive design guideline for its use as lightweight fill in roadway embankments has been unavailable. There was, therefore, a need in the United States to develop formal and detailed design documents for use of EPS-block geofoam in roadway applications.

To learn more about the project, go here.  Click this link to download the project report.

And speaking of slopes and slides, RockMan has some posts on a recent slope failure in a copper mine in Utah and one on the WSDOT doing some rock blasting on I-90 (with cool video!).  Check them out:

WSDOT rock blasting on I-90 for Snoqualmie Pass

Bingham Canyon Slide

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.

Now Published! NCHRP Synthesis 418–Developing Production Pile Driving Criteria From Test Pile Data

nchrp_syn_418 - pile criteria from test pilesThe Transportation Research Board of the National Academies has published a National Cooperative Highway Research Program synthesis report by Dan and Robert: NCHRP Synthesis 418–Developing Production Pile Driving Criteria From Test Pile Data. This synthesis provides a survey of the current practices used by transportation agencies to develop pile driving criteria, with special attention on the use of test pile data. The report covers issues related to developing driving criteria, the current practices used by the responding agencies, recommended useful practices that were identified, along with descriptions of the practical approach several agencies use to integrate a range of technologies to develop pile driving criteria under typical conditions. The information collected indicates that practices used by transportation agencies to develop pile driving criteria for production pile installation can be described as highly variable in terms of the level and sophistication of the testing performed.

Included in the report are:

  • Responses from a survey sent to all 50 state departments of transportation plus the District of Columbia and Puerto Rico (44 of the 52 agencies provided responses).
  • Interviews performed by telephone or in-person of nine of the responding agencies selected based on the written survey responses.
  • A comprehensive literature review on the range of practices included in test pile programs and their use in developing production pile driving criteria.
  • Discussions of the survey results.
  • Useful practices identified from the surveys.
  • Identification of research needs for this topic.

To purchase the print version of this report or get a PDF, follow this link to TRB.  Click the “View This PDF” to get the PDF.

Please note that if you order the printed version,  Appendices B and C (copies of the completed survey forms and interview notes) are available via download only.