TRB Webinar: Static and Seismic Design of Piles for Downdrag

October 04, 2018 02:00 PM - 03:30 PM U.S. Eastern
Cost (for your seat)
Professional Development Hours for this webinar
1.5 hour(s)
Continuing Education Hours for this webinar
AAE: 0.0 hour(s)
AICP: 0.0 hour(s)
CLE: 0.0 hour(s)

TRB will conduct a webinar on Thursday, October 4, 2018 from 2:00 PM to 3:30 PM ET that will discuss the fundamental behavior of piles subject to downdrag. Presenters will discuss utilizing the neutral plane method for evaluating downdrag in order to understand the design of both static and seismic piles. Many bridges are constructed in areas where there is compressible or liquefiable soil, which necessitates the consideration of downdrag forces and associated settlement. Downdrag for static and seismic conditions places greater demands on foundations and may lead to higher construction costs. This webinar is based upon a workshop from the 2018 TRB Annual Meeting.

This webinar was organized by the TRB Standing Committees on Seismic Design and Performance of Bridges and Foundations of Bridges and Other Structures.

Some registrants will need to pay $95 to attend this webinarSign into to view registration information.

Webinar Presenter

  • Timothy Siegel, Dan Brown and Associates

Moderated by:  Sharid Amiri, California Department of Transportation

Webinar Outline

  1. Purpose and background
  2. Neutral plane method for unified design of piles
  3. Review of AASHTO specifications on downdrag
  4. Pile-soil interaction and downdrag
  5. Static loading considerations
  6. Seismic and liquefaction considerations
  7. Question and answer session

The first 60 minutes of the webinar will be for presentations and the final 30 minutes will be reserved for audience questions. The Registered Continuing Education Program (RCEP) categorizes this webinar activity as relating to health, safety, and welfare including core technical.

Learning Objectives

At the end of this webinar, participants will be able to:

  • Describe the current AASHTO downdrag specifications
  • Discuss the differences between negative skin friction and downdrag
  • Describe the fundamental physical response of piles subjected to downdrag forces
  • Describe some of the current AASHTO code limitations of the neutral plane method

Professional Development Hour Information

A certificate for 1.5 Professional Development Hours (PDHs) will be provided to Professional Engineers (PEs) who register and attend the webinar as an individual. For groups, only the person that registers and attends the session will receive a PDH certificate. Certificates of Completion will be issued only to individuals who register for and attend the entire webinar session.

Individuals registered as Florida PEs are no longer required to email TRB with your license number to report your attendance. Instead, please use your certificate that TRB provides through as verification of your attendance to the Florida Board of Professional Engineers.

Please check with your licensing board to ensure that TRB webinar PDHs are approved by your board.

This webinar was developed in March 2018. TRB has met the standards and requirements of the Registered Continuing Education Program (RCEP). Credit earned on completion of this program will be reported to RCEP by TRB. Complaints about registered providers may be sent to RCEP, 1015 15th Street, NW, 8th Floor, Washington, DC 20005. Website:

Registration questions? Contact Reggie Gillum at