U.S. Department of Transportation
Federal Highway Administration
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: FHWA-HRT-09-006 Date: Sept/Oct 2009|
Publication Number: FHWA-HRT-09-006
Issue No: Vol. 73 No. 2
Date: Sept/Oct 2009
Below are brief descriptions of communications products recently developed by the Federal Highway Administration's (FHWA) Office of Research, Development, and Technology. All of the reports are or will soon be available from the National Technical Information Service (NTIS). In some cases, limited copies of the communications products are available from FHWA's Research and Technology (R&T) Product Distribution Center.
When ordering from NTIS, include the NTIS publication number (PB number) and the publication title. You also may visit the NTIS Web site at www.ntis.gov to order publications online. Call NTIS for current prices. For customers outside the United States, Canada, and Mexico, the cost is usually double the listed price. Address requests to:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Toll-free number: 800-553-NTIS (6847)
Web site: www.ntis.gov
Requests for items available from the R&T Product Distribution Center should be addressed to:
R&T Product Distribution Center
Szanca Solutions/FHWA PDC
13710 Dunnings Highway
Claysburg, PA 16625
For more information on R&T communications products available from FHWA, visit FHWA's Web site at www.fhwa.dot.gov, the Turner-Fairbank Highway Research Center's Web site at www.fhwa.dot.gov/research/tfhrc/, the National Transportation Library's Web site at http://ntl.bts.gov, or the OneDOT information network at http://dotlibrary.dot.gov.
Hydrodynamic Forces on Inundated Bridge Decks
Publication No. FHWA-HRT-09-028
When a bridge crossing a waterway is partially or entirely submerged during a flood event, its deck could be subjected to significant hydrodynamic loading. Accounting for the hydrodynamic forces that might be exerted on an inundated bridge deck is critical in the design of bridges. Specifically, the drag and lift forces, the moments acting on the bridge deck (unevenly distributed forces that can cause the bridge to overturn) under various levels of inundation, and a range of flow conditions influence the design and construction of bridges.
This report documents reduced-scale experiments and computer modeling that explore the forces acting on bridges. Analysts used three bridge deck prototypes for the experiments: a typical six-girder highway bridge deck, a three-girder deck, and a streamlined deck designed to better withstand hydraulic forces. The researchers measured the forces on each bridge deck shape in the laboratory with an ultraprecise force balance under a range of scenarios.
Analysts performed computational fluid dynamics (CFD) simulation modeling using two commercial software packages. They tested a range of model options from two-dimensional to three-dimensional. The analysts generated design equations for each of the bridge types and force coefficients.
According to the report, the CFD simulations seem promising as a method to test bridge designs, but more research is needed before complex designs can be tested wholly in the CFD realm. However, the design charts from the experimental results should be a valuable tool for bridge designers in a wide range of design applications.
The report is available at www.fhwa.dot.gov/publications/research/infrastructure/structures/09028/index.cfm. Printed copies are available from NTIS under order number PB2009-111423.
Corrosion Resistant Alloys for Reinforced Concrete
Publication No. FHWA-HRT-09-020
For decades, transportation agencies have recognized that deterioration of concrete bridges due to corrosion of reinforcing steel is a major technical and economic challenge. As one means of addressing the problem, researchers with the Florida Department of Transportation and Florida Atlantic University are looking at corrosion-resistant reinforcements, such as stainless steels.
In the first interim report for this project, the researchers presented results from short-term tests and preliminary results from long-term exposure of reinforced concrete slabs. This, the second interim report, provides longer term data and analyses of chloride exposures that involved four types of reinforced concrete specimens, two of which simulate northern bridge decks exposed to deicing salts, while the remaining two simulate marine substructure elements.
Researchers used three concrete mix designs. Specimen types included combinations with a simulated concrete crack, bent top bar, corrosion-resistant upper bars and black steel lower bars, and intentional clad defects such as an exposed carbon steel substrate. The exposure lasted more than 4 years. The researchers ranked the candidate alloys according to performance and analyzed how they might perform in actual concrete structures.
The report is available at www.fhwa.dot.gov/publications/research/infrastructure/structures/09020/index.cfm.
Long-Term Bridge Performance Program (Brochure)
Publication No. FHWA-HRT-09-033
In April 2008, FHWA's Office of Infrastructure Research and Development launched the Long-Term Bridge Performance (LTBP) program, a flagship research project with the objective of collecting scientific-quality data on the Nation's highway bridges. FHWA envisions the LTBP as a 20-year or longer examination of highway bridges to improve knowledge of bridge performance and ultimately promote the safety, mobility, longevity, and reliability of the country's highway transportation assets. This brochure details the program's objectives and methodologies.
The LTBP program aims to compile a comprehensive database of quantitative information from a representative sample of bridges nationwide, looking at critical bridge elements and the factors that affect their performance—age, material, design, condition, use, and environment. By taking a holistic approach and analyzing the physical and functional variables that affect bridge performance, the program will provide a more detailed and timely picture of bridge health and better tools for bridge management.
Printed copies of the brochure are available from FHWA's Office of Infrastructure Research and Development by phone at 202-493-3024, fax at 202-493-3442, or e-mail Monique Smith at firstname.lastname@example.org.