U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| Project Information | ||
| Project ID: | FHWA-PROJ-12-0053 | |
| Project Name: | Fatigue of Plasma and Laser Cut Holes | |
| Project Status: | Active | |
| Start Date: | June 1, 2012 | |
| End Date: | January 1, 2015 | |
| Contact Information | ||
| Last Name: | Ocel | |
| First Name: | Justin | |
| Telephone: | 202-493-3080 | |
| E-mail: | justin.ocel@dot.gov | |
| Office: | Office of Infrastructure Research and Development | |
| Team: | Bridge and Foundation Engineering Team [HRDI-40] | |
| Program: | High-Performing Steel Bridge | |
| Laboratory: | Structures Laboratory | |
| Project detail | ||
| Roadmap/Focus area(s): | Infrastructure Research and Technology Strategic Plan and Roadmap | |
| Project Description: | This project will determine the fatigue strength of plates that have plasma (and possibly laser) cut holes in them. The initial matrix of specimens will be procured from three different sources that will be using different plasma-cutting machines and controlling software. The initial matrix of specimens will determine the effect on fatigue strength that the type of plasma shielding (either oxygen or air), steel type (either regular carbon or weathering grades), and the orientation of the cut termination relative to the primary stress direction may have. In addition, the hardness and cylindricality of the holes from the three different sources will be correlated to the fatigue strength to understand if it is dependent upon the machine making the cut and its controlling software. The project may also address the static strength of plasma cut holes, though this will be dependent upon procurement of a larger testing machine that has been programmed. | |
| Goals: | To determine the fatigue strength of plasma (and possibly laser) cut holes in steel plates. This fatigue strength would be compared to that of a drilled hole that is the currently accepted technique in steel bridge fabrication. | |
| Background Information: | In Article 11.4.8.1 of the 2010 American Association of State Highway and Transportation Officials Load and Resistance Factor Design Bridge Construction Specifications states that bolt holes shall only be made by drilling or punching. Though a provision is provided in the commentary that "with the owners approval, round or slotted holes for non-main members in thin plate may successfully be thermally cut by plasma, laser, or oxygen-acetylene means." However, many owners choose not to exercise this clause because there is no data to show how these holes perform under static and fatigue loading. At the same time, current machines used in steel bridge fabrication have the ability to perform multiple fabrication processes at one time, reducing the amount of handling, thus leading to reduced fabrication costs. Until this research proves otherwise, steel bridge fabricators will have to continue performing multiple material-handling steps to accommodate standard drilling and punching operations. | |
| Product Type: | Technical report | |
| Test Methodology: | Full-scale experimental | |
| Expected Benefits: | Reduced steel bridge fabrication costs. | |
| Deliverables: | Name: WORKING TITLE - "Fatigue Strength of Thermally Cut Holes in Steel Plate." Product Type(s): Technical report Description: A report to document all aspects of the testing, including methodology, testing matrix, results, and conclusions. | |
| FHWA Topics: | Research/Technologies--Turner-Fairbank Highway Research Center (TFHRC) | |
| TRT Terms: | Fatigue (Mechanics) Infrastructure Research Steel Bridges Metal Cutting Fatigue Strength Bridges |
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| FHWA Disciplines: | Structures |
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| Subject Areas: | Bridges and other structures Research |
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