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The National Academies

NCHRP 24-28 [Completed]

LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-Reinforced Systems in Geotechnical Applications

  Project Data
Funds: $600,000
Research Agency: McMahon & Mann Consulting Engineers, P.C.
Principal Investigator: Kenneth L. Fishman
Effective Date: 6/1/2006
Completion Date: 6/30/2010
Comments: The project final report is available as NCHRP Report 675.

Transportation agencies use a variety of metal-reinforced systems in geotechnical applications, including soil and rock reinforcements, ground anchors, and tiebacks. These systems support retaining walls and soil and rock slopes and stabilize roadway cuts and fills. The precise conditions governing the deterioration of these systems are uncertain, but corrosion is known to have an impact on their service life. Engineers, faced with the task of allocating budgets to rehabilitate aging facilities, need reliable techniques for assessing corrosion and estimating metal loss. Service-life estimates for new systems need to be improved, and consideration of metal loss in their design needs to be consistent with the reliability-based approach adopted in the AASHTO LRFD (Load and Resistance Factor Design) Bridge Design Specifications.

The objectives of this project were to (1) assess and improve the predictive capabilities of existing computational models for corrosion potential, metal loss, and service life of metal-reinforced systems used in retaining structures, highway cuts and fills, and other applications; (2) develop methodology that incorporates the improved predictive models into an LRFD approach for the design of metal-reinforced systems; and (3) recommend additions and revisions to the AASHTO LRFD specifications to incorporate the improved models and methodology.

The project final report is available as NCHRP Report 675: LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-Reinforced Systems. Appendices C, D, and E are available by downloading this ZIP file (29 MB).

NCHRP Project 24-28A, Validate the Results of NCHRP Project 24-28 , was subsequently conducted to further validate some key results of Project 24-28. The project final report for Project 24-28A is available here for download. A summary is available as NCHRP Research Results Digest 364, Validation of LRFD Metal Loss and Service-Life Strength Reduction Factors for Metal-Reinforced Systems.


 


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