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Bridges & Structures



This is an archived publication. It may be useful for researchers doing further work in this area as well as those developing improved testing and design procedures and is included because of its historical value

Stream Stability at Highway Structures Third Edition

Stream Stability at Highway Structures, Hydraulic Engineering Circular No. 20 (HEC-20), provides guidelines for identifying stream instability problems at highway stream crossings. It is a dual unit update of the second edition published in 1995. The HEC-20 manual covers geomorphic and hydraulic factors that affect stream stability and provides a step-by-step analysis procedure for evaluation of stream stability problems. Stream channel classification, stream reconnaissance techniques, and rapid assessment methods for channel stability are summarized. Quantitative techniques for channel stability analysis, including degradation analysis, are provided, and channel restoration concepts are introduced.

There are two companion documents, Evaluating Scour at Bridges (HEC-18) and Bridge Scour and Stream Instability Countermeasures (HEC-23). These three documents contain updated material from previous editions and the publication Interim Procedures for Evaluating Scour at Bridges issued in September 1988 as part of the FHWA Technical Advisory T 5140.20, Scour at Bridges. T5140.20 has since been superseded by T5140.23, Evaluating Scour at Bridges dated October 28, 1991.

  • FHWA Publication Number: NHI-01-002
  • Publication Year: 2001

Other documents in this series:

Updated: 04/11/2022
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