TRB Webinar: Seismic Design of Bridge Abutments

September 28, 2017 02:00 PM - 04:00 PM U.S. Eastern
Cost (for your seat)
Professional Development Hours for this webinar
2.0 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, September 28, 2017, from 2:00 PM to 4:00 PM ET that will explore the latest research about theories on computing the ultimate passive force for abutment deflection. The webinar will highlight simple models and equations using different materials and geometries. The presenter will discuss the effect of cyclic loading on lateral resistance and damping. They will also provide case examples and present the results of a series of full-scale tests.

This webinar was organized by the TRB Standing Committee on Seismic Design and Performance of Bridges.

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

Webinar Presenters

  • Kyle Rollins, Brigham Young University

Moderated by: Ken Fishman, McMahon and Mann Consulting Engineers, PC

Webinar Outline

  1. Seismic loadings on bridges (inertia forces and lateral spreading)
  2. Passive force on bridge abutments
    • Methods for computing ultimate passive force
      • Rankine
      • Coulomb
      • Log-Spiral
      • Caltrans
    • Ultimate passive force and simplified passive force-deflection relationships (backbone curves)
      • Dense granular backfills (sands, gravels)
      • Loose granular backfills (sands)
      • Flowable fill and cellular concrete backfill
      • Geofoam backfill inclusions to reduce transfer of pass
    • Simplified models to account for non-linear passive force-deflection relationships
    • Accounting for cyclic loading effects on passive force and damping
    • Accounting for bridge skew effects on passive force-deflection curves
  3. Lateral Abutment Pile Resistance
    • Soil properties of granular backfill for lateral pile analysis
    • Reduced lateral resistance due to group interaction using p-multipliers.
    • Reduced lateral pile resistance based on p-multipliers near MSE walls
  4. Induced force on the MSE reinforcements
  5. Question and answer session

The first 90 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:

  1. Understand the differences between available methods for computing ultimate passive force and correctly compute ultimate passive force for four different materials, including: dense backfills, loose backfills, flowable fills/cellular concrete, and geofoam inclusions
  2. Compute and adjust passive force for several characteristics, including: backbone curves, skew angle of the abutment, and cyclic loading
  3. Understand how to select soil parameters for lateral pile analysis of abutment piles
  4. Use p-multipliers to reduce lateral pile resistance due to group interaction and piles near MSE walls

Professional Development Hour Information

A certificate for 2.0 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 2017. 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