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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - January/February 2013

January/February 2013
Issue No:
Vol. 76 No. 4
Publication Number:
Table of Contents

Training Update

Ensuring the Integrity of Bridges

by Candice Jackson

In April 1987, a catastrophic failure of the Schoharie Creek bridge on the New York State Thruway caused 10 deaths. The bridge's collapse was partially attributed to the effects of bridge scour, damage caused by sediment carried by swiftly moving water abrading the bridge's abutments or piers. Today, scour continues to compromise the integrity of the Nation's bridges, even as engineers and inspectors work to analyze and address potential problems and minimize the effects. To equip engineers with the latest knowledge on this subject, the National Highway Institute (NHI) offers course 135046 Stream Stability and Scour at Highway Bridges.

Changes to Federal Guidance

Material covered in this course is primarily drawn from two Hydraulic Engineering Circulars (HEC) published by the Federal Highway Administration (FHWA): Evaluating Scour at Bridges, 5th Edition (HEC-18), and Stream Stability at Highway Structures, 4th Edition (HEC-20), both updated in 2012. Since 2001, FHWA and the Transportation Research Board have sponsored various research projects resulting in new guidance for bridge owners and engineers. NHI recently revamped course 135046 to reflect the latest updates to the circulars.

"Participants learn and apply the most recent research, deployment, and policy approaches related to scour," says Joseph Krolak, Hydraulics and Geotechnical team leader for FHWA's Office of Bridge Technology. "Incorporating risk-based, data-driven ideas from the scour program aligns the course with important concepts recently enacted within MAP-21 that we hope will allow safer, more cost effective and focused designs and analyses."

The 3-day, instructor-led training presents lessons on stream and stability factors, as well as preventive techniques for identifying, analyzing, and calculating various hydraulic factors that affect bridge stability. In addition to the standard course curriculum, hosting organizations can select three lessons from a list of eight optional ones: Effects of Debris on Pier Scour, Quantitative Techniques for Channel Stability Analysis, Abutment Scour Problem Session, Complex Pier Scour, FDOT Pier Scour Methodology, Quantitative Techniques for Degradation Analysis, Channel Stability Processes in Gravel-Bed Rivers, and Techniques for Evaluating Pier Scour in Erodible Rock.

Before each session, instructors contact the host organization to complete a pre-course questionnaire to determine which three optional lessons will be taught. These options ensure that each session meets the specific training needs of the host organization.

Facilitating Participant Engagement

Instructors present the course content using a variety of methods, enabling participants to incorporate the information presented into activities drawn from situations they would encounter in the field. In addition, the course features an interactive technology that enables participants to anonymously answer questions raised by the instructor.

"The answers are visible to the entire class, but identities of those who answered are not," says Dr. Peter Lagasse of Ayres Associates, one of the course instructors. "This enables instructors to monitor whether the concepts are being absorbed and understood, while ensuring that participants are comfortable enough to share their answers."

At the conclusion of the course, participants work in groups during a 2-3 hour workshop. Each group applies the qualitative and quantitative analyses they learned to a real-world scenario to determine if a Scour Plan of Action is required to remedy the situation described in the scenario.

This training is ideal for hydraulic, structural, and geotechnical engineers responsible for assessing possible hydraulic-related problems and maintaining the integrity of highway bridges. Although the course is intended for engineers, bridge inspectors and consultants who perform bridge engineering work also will benefit.

Recommended Prerequisites

NHI offers several Web-based trainings in the hydraulics program, which participants are strongly encouraged to complete before enrolling in this course. These include 135091 Basic Hydraulic Principles Review, 135086 Stream Stability Factors and Concepts, and 135087 Scour at Highway Bridges: Concepts and Definitions.

"Transportation professionals are busy, so these Web-based trainings are available online to minimize their time away from the office," says Louisa Ward, a training program manager with NHI. "Understanding the concepts covered in these Web-based sessions will help participants absorb the information presented in course 135046 Stream Stability and Scour at Highway Bridges, and ensure that they get the maximum benefit from the training."

Construction of this bridge on Interstate 35W in Minneapolis, MN, involved investigating the potential effects of scour on the foundation.


Candice Jackson is a contractor for NHI.