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This report is an archived publication and may contain dated technical, contact, and link information
Publication Number:  FHWA-HRT-17-020    Date:  February 2017
Publication Number: FHWA-HRT-17-020
Date: February 2017


Optimization of Rib-to-Deck Welds for Steel Orthotropic Bridge Decks

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This report documents fatigue testing results of full-scale geometries of various orthotropic rib-to-deck weld geometries. The Federal Highway Administration undertook this study in order to assess these weld geometries and potentially provide performance data that might alleviate restrictive fabrication specifications. Currently, these restrictions are reducing the competitiveness of orthotropic steel decks versus other alternatives. Parameters explored in the research were welding process, weld penetration, and fit-up tolerance. The results showed that fatigue resistance could be assured in design through simple fabrication rules that define the weld leg size and target penetration and, if implemented, should make rib-to-deck welds more fabricator-friendly to produce while still maintaining reliability against fatigue failures.

This report will benefit those interested in the design and fabrication of steel orthotropic bridge decks, including State transportation departments, steel bridge fabricators, design consultants, and researchers.

Cheryl Richter
Director, Office of Infrastructure
Research and Development


This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.

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Technical Report Documentation Page

1. Report No.


2. Government Accession No. 3 Recipient's Catalog No.
4. Title and Subtitle

Optimization of Rib-to-Deck Welds for Steel Orthotropic Bridge Decks

5. Report Date

February 2017

6. Performing Organization Code
7. Author(s)

J.M. Ocel, B. Cross, W.J. Wright, and H. Yuan

8. Performing Organization Report No.


9. Performing Organization Name and Address

Office of Infrastructure Research & Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296

Virginia Polytechnic Institute and State University
Civil and Environmental Engineering Department
1880 Pratt Drive
Blacksburg, VA 24060-6343

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

DTFH61-04-C-00029 including Task Orders 28–30

DTFH061-10-D-00017 including Task Order 2

12. Sponsoring Agency Name and Address

Office of Infrastructure Research and Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296

13. Type of Report and Period Covered

Final Report, October 2009–July 2012

14. Sponsoring Agency Code


15. Supplementary Notes

Justin Ocel (HRDI-40) conducted the testing at Turner-Fairbank Highway Research Center, was the technical monitor of all task orders, and prepared the final report with assistance from onsite contractor staff under both contracts. The Contracting Officer’s Representative for both contracts was Fassil Beshah (HRDI-40).

16. Abstract

Orthotropic steel decks have been widely used over the decades, especially on long-span bridges as a result of their lightweight and fast construction. However, fatigue cracking problems have been observed in the welds in many cases because of wheel loads. The rib-to-deck welds need special care because they are directly located under wheel loads and are subjected to both local and global stress effects.

When this research began, the current practice in the United States was to use a one-sided partial penetration weld joining the rib and deck plates together with a minimum of 80-percent penetration requirement. Melt-through and blow were also considered rejectable defects. Restrictive requirements such as these result in a very narrowly defined welding procedure with little tolerance for variation. In practice, this leads to numerous weld repairs and rigorous inspection requirements that drive up the cost of orthotropic deck fabrication.

This study shows that the 80-percent penetration requirement can be significantly relaxed because fatigue performance was largely dictated by weld size and not penetration. A simple correlation is provided between weld size and penetration to guarantee American Association of State and Highway Transportation Officials category C fatigue performance that should provide for more relaxed fabrication specifications. Finally, specimens fabricated with purposeful fit-up gaps were found to close provided the original gap did not exceed 0.020 inch.

17. Key Words

Local structural stress, steel bridge, orthotropic steel deck, fatigue testing

18. Distribution Statement

No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161.

19. Security Classification
(of this report)


20. Security Classification
(of this page)


21. No. of Pages


22. Price


Form DOT F 1700.7 (8-72) Reproduction of completed page authorized




Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101