Transportation Research Board 2002 Annual Meeting Presentations from Workshop on Plan of Action for Scour Critical Bridges

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Slide 1

Workshop on Plan of Action for Scour Critical Bridges

Transportation Research Board
2002 Annual Meeting

Sponsored By
A2A03 Committee on Hydrology,
Hydraulics and Water Quality

Slide 2

SESSIONS 582 AND 610

• J. Sterling Jones - FHWA
• Peter F. Lagasse - Ayres Associates
• Jorge E. Pagan-Ortiz - FHWA
• David R. Pearson - GKY & Associates

Slide 3

OVERVIEW AND UPDATES TO HEC 18, 20, AND 23

P.F. Lagasse, Ph.D., P.E.
Transportation Research Board
2002 Annual Meeting

Sponsored By
A2A03 Committee on Hydrology,
Hydraulics and Water Quality

Slide 4

BRIDGE SCOUR
CATASTROPHIC FAILURES

• Schoharie Creek, New York - 1987
• Hatchie River, Tennessee - 1989
• I-5 (Los Gatos Creek), California - 1995

Slide 5

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Slide 8

BRIDGE SCOUR
A WIDESPREAD PROBLEM

• 481,251 Bridges over Water
• 25,858 Scour Critical
• 88,686 Unknown Foundations

Slide 9

A DECADE OF RESEARCH
EDUCATION AND TRAINING

• HEC-18 Bridge Scour
• HEC-20 Stream Stability
• HEC-23 Countermeasures
• ASCE Compendium on Bridge Scour
• 1998 European Scanning Review
• 1999 New Zealand Scanning Review

Slide 10

COMPREHENSIVE METHODOLOGY

HEC-20 --> HEC 18 --> HEC-23

Slide 11

HEC-18 REVISIONS (FOURTH EDITION)

• Reorganize by Topic
• Move Countermeasure Design to HEC-23
• Pier Scour in Coarse Material (K4)
• Scour for Complex Pier Foundations
• Pressure Flow Scour
• Alternative Approaches for Abutment Scour
• Special Considerations
  • Plan of Action
  • Item 113 Coding Revisions
  • Scour in Cohesive Soils
  • Scour in Rock
  
  

Slide 12

HEC-20 REVISIONS (THIRD EDITION)

• Move Countermeasure Selection and Design to HEC-23
• Stream Reconnaissance, Classification, and Response
• Rapid Assessment Method
• Quantitative Analysis Techniques
  • Lateral Stability (Meander)
  • Vertical Stability (Degradation)
  • Sediment Continuity
  
  
• Channel Restoration Concepts
• Geotechnical Considerations for Bank Stability

Slide 13

HEC-23 REVISIONS
(SECOND EDITION)

• Becomes the Primary Reference
  for Countermeasure Design
• Strategies for Plan of Action
• Hydraulic Analysis
  • Physical Modeling
  • Scour at Transverse Structures
  • Scour at Longitudinal Structures
  
  
• Special Considerations for Riprap and Filter Design

Slide 14

HEC-23 REVISIONS
(SECOND EDITION)

• Biotechnical Engineering
• Guidance from Outside U.S.
• Instrumentation and Monitoring
• Additional Design Guidelines
  • Design Procedure for Grout Filled Mattresses
  • Modular Design for Concrete Armor Units
  • Revetment Guidelines from HEC-11
  
  

Slide 15

TRAINING COURSE REVISIONS

• Stream Stability and Scour (HEC-18 & 20)
• Countermeasure Design (HEC-23 and DP 97)
• Update 1-Day Bridge Inspectors Course
• Develop Course Materials for HDS6

Slide 16

HDS 6 REVISIONS

• Update Technology from 1970s to 1990s
• Expanded Sediment Transport Chapter
  • Comprehensive Comparison of Formulas
  • Formula Selection based on Transport Mode
  • New Sediment Transport Relationships
  
  
• More Channel Response Case Studies
• Better Integration with HEC-18, -20, & -23
• To Be Issued as HDS-6

Slide 17

HDS 6

• River Engineering for Highway Encroachments -
  Highways in the River Environment
• REHIRE

Slide 18 -19

STREAM STABILITY AND SCOUR AT HIGHWAY BRIDGES NHI COURSE 135046

Overall Course Learning Objectives

1. Identify stream instability and scour problems at bridges
2. Conduct a stream stability reconnaissance
3. Classify the stream, identify potential problems, and conduct a qualitative analysis of response
4. Calculate long-term degradation quantities
5. Calculate general and local scour at bridge piers and abutments for simple and complex substructures
6. Plot and evaluate the total scour prism
7. Define and compare channel restoration and channel rehabilitation concepts
8. Draft a Plan of Action for correcting stream instability and scour problems

Slide 20 - 21- 22

COUNTERMEASURE DESIGN FOR BRIDGE SCOUR AND STREAM INSTABILITY
NHI Course 135048

Overall Course Learning Objectives

1. Prepare a Plan of Action for correcting stream instability and scour problems considering a range of countermeasure options and strategies
2. Select appropriate countermeasures considering functional applications and river characteristics
3. Estimate scour at longitudinal and transverse structures
4. Describe the advantages and disadvantages of biotechnical engineering
5. Describe a range of alternatives to conventional riprap and filter techniques for local scour protection
6. Design channel instability and bridge scour countermeasures for specific stream instability or scour problems
7. Describe other countermeasures for stream instability and scour and evaluate their
   performance
8. Given a scour critical bridge, select and design a monitoring program to reduce the risk from scour
9. Integrate portable and fixed instruments into a monitoring program

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