View PDF Version (332 Kb)
The Federal Highway Administration, at the request of the Connecticut Department of Transportation, has investigated the flexural capacity of a set of prestressed concrete adjacent box beams that were damaged in a fire. The U.S. Route 7 bridge over the Norwalk River near Ridgefield, CT was damaged when a gasoline tanker crashed and caught fire on the bridge. During the replacement of the superstructure of this bridge, four beams were saved and transported to the Turner-Fairbank Highway Research Center. Full-scale structural tests were completed on the beams to determine their flexural behavior through ultimate failure. Additional visual and petrographic examinations were also completed. In summary, the investigation found that the flexural capacity of the beams had not been degraded significantly as compared to their anticipated capacity; however, their long-term durability may have been degraded by the fire. This report presents the results of this experimental investigation.
Gary L. Henderson
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. This report does not constitute a standard, specification, or regulation.
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.
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.
1. Report No. FHWA–HRT–07–024 |
2. |
3. Recipient's Accession No. |
|
4. Title and Subtitle Flexural Capacity of Fire-Damaged Prestressed Concrete Box Beams |
5. Report Date February 2007 |
||
6. | |||
7. Author(s) Benjamin A. Graybeal |
8. Performing Organization Report No. |
||
9. Performing Organization Name and Address PSI, Inc. |
10. Project/Task/Work Unit No. |
||
11. Contract (C) or Grant (G) No. |
|||
12. Sponsoring Organization Name and Address Office of Research and Technology Service |
13. Type of Report and Period Covered Final Report, December 2005 - July 2006 |
||
14. Sponsoring Agency Code | |||
15. Supplementary Notes Additional FHWA Contacts - William Wright, Contract Officer's Technical Representative |
|||
16. Abstract A gasoline tanker truck fire caused significant damage to an adjacent member box-beam bridge in southwestern Connecticut. It was unclear whether the type of damage that these box beams experienced was sufficient to critically impair the structure's ability to serve its intended purpose. Four of the beams were removed from the bridge and were loaded in flexure to failure. These tests indicated that each of the beams retained sufficient flexural capacity to resist a 1,572 kilonewton-meter (kN-m) (1,160 kip-feet (kip-ft)) moment prior to ultimate flexural failure. This value is greater than the rated ultimate flexural capacity of each beam. As such, it seems that these beams had sufficient remaining flexural capacity to serve their intended purpose in the immediate aftermath of the fire. The long-term viability of these beams is more questionable. The visual and petrographic examinations indicated that the damage to the bottom flange concrete was sufficient to allow pathways through the concrete to the depth of the bottom strands. Therefore, it is possible that fire may have acted to allow for the accelerated deterioration of the superstructure and thus decreased the long-term flexural capacity of the bridge. |
|||
17.Document Analysis/Descriptors Fire Damage, Prestressed Concrete, Adjacent Box Beam Bridge, Flexural Capacity |
18. Availability Statement
|
||
19. Security Classif. (of this report) Unclassified |
20. Security Classif. (of this page) Unclassified |
21. No. of Pages 35 |
22. Price
|
Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
SI (Modern Metric) Conversion Factors
FHWA-HRT-07-024
TFHRC Home | FHWA Home | Feedback United States Department of Transportation - Federal Highway Administration |