Event Title

Yellowstone River at Huntley, MT: Bridge Scour Countermeasure Failure Investigation

Presenter Information

Russell Brewer, MTDOT

Streaming Media

Duration

00:24:08

Start Date

8-20-2014 11:20 AM

End Date

8-20-2014 11:45 AM

Abstract

The Highway 312 crossing the Yellowstone River at Huntley Montana was subjected to back to back major floods in 1996 and 1997. The 1998 bridge underwater inspection report indicated that scour had exposed the pier footings at pier 3, 6, and 7. Subsequent investigations by the Montana Department of Transportation indicated that scour had penetrated to the bottom or below the base of the footings at piers 6 and 7. In 2006 a scour mitigation project was completed using cabled articulated concrete blocks placed around the footings at piers 3, 6, and 7.

In the spring of 2011 the Yellowstone River and the local tributaries in the area experienced significant flooding. The underwater bridge inspection completed in the fall of 2011, indicated that the countermeasures installed at pier 6 have failed. A bathymetric survey and a SRH-2D model were used to examine the extent of the scour hole and flow characteristics around the pier to determine the factors that contributed to the failure of the installed countermeasures. The presentation will address the site history and the forensic investigation into why the countermeasures failed.

Contact Information

Mr. Russell Brewer

Bridge Scour Engineer

Highways Bureau

Montana Department of Transportation

2701 Prospect Avenue

Helena, MT 59620-1001

Phone: 406-444-7208

email: rbrewer@mt.gov

Speaker's Biography

Russell Brewer, P.E., has served as the Montana Department of Transportation (MDT) Scour Engineer for 11-years. He coordinates and oversees the statewide Bridge Scour Program to assess the structural integrity, longevity, and related monitoring and mitigation requirements according to Department, FHWA, USGS, and professional engineering standards. His responsibilities include establishing and maintaining program priorities, policies, and procedures ensuring that MDT’s statewide bridge scour program is in compliance with Federal Highway Administration (FHWA) regulations. Serves as the Department’s authority in bridge scour assessment and mitigation and is accountable for the quality, efficiency, and cost-effectiveness of mitigation alternatives, design procedures, and results delivered on monitoring, mitigation, and replacement projects. Coordinates and oversees bridge scour assessments. Conducts and reviews engineering analyses, field inspections, and provides recommendations regarding structural monitoring, mitigation, and/or replacement. Oversees the development of hydraulic engineering components of designs and mitigation plans, and provides expert consultation and advice throughout the mitigation process to ensure conformance with engineering standards. Provides expertise and guidance to Department engineers, cooperative agencies (e.g., USGS), and others regarding bridge scour assessments and mitigation measures. Directs and coordinates specialized research projects to evaluate new methods and technologies for assessing and mitigating bridge scour.

Rights

Copyright © 2014, Russell Brewer

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Aug 20th, 11:20 AM Aug 20th, 11:45 AM

Yellowstone River at Huntley, MT: Bridge Scour Countermeasure Failure Investigation

The Highway 312 crossing the Yellowstone River at Huntley Montana was subjected to back to back major floods in 1996 and 1997. The 1998 bridge underwater inspection report indicated that scour had exposed the pier footings at pier 3, 6, and 7. Subsequent investigations by the Montana Department of Transportation indicated that scour had penetrated to the bottom or below the base of the footings at piers 6 and 7. In 2006 a scour mitigation project was completed using cabled articulated concrete blocks placed around the footings at piers 3, 6, and 7.

In the spring of 2011 the Yellowstone River and the local tributaries in the area experienced significant flooding. The underwater bridge inspection completed in the fall of 2011, indicated that the countermeasures installed at pier 6 have failed. A bathymetric survey and a SRH-2D model were used to examine the extent of the scour hole and flow characteristics around the pier to determine the factors that contributed to the failure of the installed countermeasures. The presentation will address the site history and the forensic investigation into why the countermeasures failed.