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Publication Number:  FHWA-HRT-20-056    Date:  August 2020
Publication Number: FHWA-HRT-20-056
Date: August 2020


Evaluation of Holes Fabricated Using Plasma Arc Cutting

PDF Version (20 MB)


This report documents fatigue and tensile test results of steel plates with round holes fabricated using plasma arc cutting. Bridge owners, designers, and fabricators have shown interest in using plasma arc cutting as a more economical alternative to traditional hole fabrication methods. However, a lack of experimental data demonstrating the behavior of plasma-cut holes under fatigue and tensile loading has hindered their use in steel bridge design and fabrication. FHWA initiated this study to categorize the fatigue and static tension resistance of plasma-cut holes in steel bridge members. This research establishes the design fatigue resistance and assesses the fracture behavior of steel members with plasma-cut holes. Multiple plasma-cutting processes were evaluated. Results showed that fatigue resistance of plasma-cut holes is lower compared to current hole-making methods. Tensile testing showed that certain plasma-cutting processes could cause brittle failure modes in tension members with plasma-cut holes.

This report will benefit those interested in the design and fabrication of round holes in steel bridge members, including State departments of transportation, bridge design consultants, bridge owners, steel bridge fabricators, and researchers.

Cheryl Allen Richter, P.E., Ph.D.
Director, Office of Infrastructure
Research and Development


This document is disseminated under the sponsorship of the U.S. Department of Transportation (USDOT) 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.

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.


Technical Report Documentation Page

1. Report No.


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

Evaluation of Holes Fabricated Using Plasma Arc Cutting

5. Report Date

August 2020

6. Performing Organization Code
7. Author(s)

Christopher Beckett, Ph.D., P.E., and Justin Ocel, Ph.D., P.E. (ORCID 0000-0002-0176-7276)

8. Performing Organization Report No.
9. Performing Organization Name and Address

Professional Service Industries, Inc.
13873 Park Center Road, Suite 315
Herndon, VA 20171

10. Work Unit No. (TRAIS)
11. Contract or Grant No.


12. Sponsoring Agency Name and Address

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

13. Type of Report and Period Covered

Final Report; June 2012–October 2016

14. Sponsoring Agency Code


15. Supplementary Notes

The work reported herein was conducted under Federal Highway Administration contract support services for the structures laboratories. Justin Ocel, Ph.D. (HRDI-40), provided technical oversight/assistance as the Task Manager and wrote portions of the report. Fassil Beshah, Ph.D. (HRDI-40), served as the Contracting Officer's Representative of this contract.

16. Abstract

Modern plasma-cutting equipment and techniques can produce high-quality holes more economically than drilling and punching. However, American Association of State Highway and Transportation Officials (AASHTO) design and construction specifications do not permit the use of plasma-cut holes in primary bridge members due to a lack of experimental data demonstrating their fatigue and tensile strength. Additionally, it is uncertain if holes fabricated using plasma arc cutting meet the AASHTO requirements for hole size accuracy. This research shows that round open holes fabricated using plasma arc cutting would be an AASHTO category E fatigue detail. Bearing connections with nonpretensioned bolts installed in plasma-cut holes would be classified as category E′. Both results represent lower fatigue resistance compared to drilled or punched holes. Most tension members produced a tensile strength equal to or exceeding the theoretical nominal tensile strength. However, several tension members did not attain the theoretical nominal strength and a reduction factor was necessary when calculating the tensile resistance of a member with plasma-cut holes. Tension testing at low temperatures revealed that members with conventional plasma-cut holes can fail with brittle fracture and insignificant inelastic deformation. Lastly, the four fabricators used for this study provided a mostly consistent hole diameter over numerous samples. However, variation in diameter was large enough that close quality control was required.

17. Key Words

Steel bridge, plasma arc cutting, bridge fabrication, hole-making, fatigue

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


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