Tag Archives: LADOTD

Bridge Foundations, Drilled Shafts, Load Testing

Huey P. Long Bridge Expansion–Completion in June 2013

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The Huey P. Long Bridge in New Orleans, Louisiana will be officially completed in June this year, according to the LADOTD. A recent article in the Times-Picayune on-line announced another ramp opening last weekend, bringing the $1.2 billion project one step closer to completion.  DBA was brought onto the project by the contractor team to consult on the design, load testing, and construction of the 9-foot diameter, 184-foot long base grouted drilled shafts.

Check out our previous DBA posts on the HPL.

This article from the Times-Picayune in 2009 gives a great graphical description of how the bridge was widened.

You can learn all about the history of the bridge and the project at the project page of the Louisiana TIMED Program.  The project page has a lot of good links, including photos from the project.

Photo Credit: Louisiana TIMED project photo album

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.