U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
|Project Name:||Steel Bridge Coatings Topics|
|Start Date:||August 1, 2013|
|End Date:||November 28, 2014|
|Office:||Office of Infrastructure Research and Development|
|Team:||Bridge and Foundation Engineering Team [HRDI-40]|
|Program:||High-Performing Steel Bridge|
|Roadmap/Focus area(s):||Infrastructure Research and Technology Strategic Plan and Roadmap|
|Project Description:||This project is addressing multiple topics under one contract to provide a better understanding of steel bridge coatings, either in design or fabrication.|
There are four objectives to this project.
1) For the Federal Highway Administration (FHWA) to publish a paper or report contrasting the pros and cons between conventional paint, galvanizing, and metalizing coatings on steel bridges.
2) Conduct a small study looking at the slip and creep resistance of metalized coating with and without sealers.
3) Conduct a interlaboratory variability study to assess the Research Council of Structural Connection compression slip testing specification and make recommendations to make that testing specification more robust to reduce variability in results from one lab to another.
4) Explore if typical steel bridge bolted connections are more often controlled by slip or strength and determine if two slip coefficients are even needed in design, or is one sufficient.
|Background Information:||Since 2006, the Federal Highway Administration (FHWA) has assembled and convened a technical working group (TWG) of steel bridge representatives from industry, academia, design consultants, and fabricators. The TWG was assembled in support of the current and planned activities relating to steel bridge research, deployment, and education and assembled by FHWA in order to facilitate stakeholder input into, and to provide a continuing source of quality assurance during a new multiyear program for steel bridge research, deployment, and education. In the last TWG meeting, some of the participants suggested FHWA consider funding research activities in steel bridge coatings with heavy consideration given to metalized coatings, as they are gaining in popularity. Two issues were highlighted by the TWG regarding this. First was a suggestion of a white paper to contrast the pros and cons between conventional paint, galvanizing, and metalizing. This white paper would give bridge owners a good introduction into the considerations that should be used in selection of these coating systems. Second was a project looking at the slip and creep coefficients of metalized coatings as there is very little data in the open literature. However, it was suggested this be expanded to cover organic zinc primers, too. There has been a propensity of organic zinc primers to fail Class B slip resistance, when the same formulation used to pass. The new data have been anecdotally described to “just barely fail” Class B slip resistance, though much of the data was proprietary, being paid for by paint manufacturers and not available for public consumption. Therefore, there is a need to take a comprehensive, but neutral, view of the slip resistance of organic zinc primers and understand the variables that might be causing abnormalities in the slip testing results. The creep resistance of organic primers need not be investigated. It is anticipated that one of the task order recommendations may be a reduction of the Class B friction factor to a value less than 0.50. The implications to steel connection design must also be explored if this is pursued.|
|Test Methodology:||Full-scale experimental testing.|
|Expected Benefits:||Better information available for bridge owners to make informed decisions on protective coatings for steel bridges.|
|Deliverables:||1. Name: WORKING TITLE - "Interlaboratory Variability of Slip Coefficient Testing for Bridge Coatings"|
Product Type(s): Technical report
Description: A contractor's final report outlining all the data collected from all the slip coefficient testing from the four participating labs
2. Name: WORKING TITLE - "FHWA Steel Bridge Design Handbook, Volume 19: Corrosion Protection of Steel Bridges, 2nd Edition"
Product Type(s): Technical report
Description: In the project objectives, it was noted that FHWA should publish a pro/con paper of steel bridge corrosion mitigation strategies. It was decided the best place for this was to expand the currently published Volume 19 of the FHWA Steel Bridge Design Handbook
3. Name: WORKING TITLE - "TECHBRIEF: Slip and Creep of Thermal Sprayed Coatings."
Product Type(s): Techbrief
Description: This will be a report of the data collected on the slip and creep testing of sealed and unsealed metalized coatings
|FHWA Topics:||Roads and Bridges--Structures|
|TRT Terms:||Steel Bridges
|Subject Areas:||Bridges and other structures