U.S. Department of Transportation
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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-2006-002 Vol. 69 No. 4 Date: January/February 2006|
Publication Number: FHWA-HRT-2006-002 Vol. 69 No. 4
Date: January/February 2006
Below are brief descriptions of products recently published online by the Federal Highway Administration's (FHWA) Office of Research, Development, and Technology. Some of the publications also may be available from the National Technical Information Service (NTIS). In some cases, limited copies are available from the 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)
Address requests for items available from:
Federal Highway Administration
R&T Product Distribution Center, HRTM-03
For more information on research and technology publications from FHWA, visit the Turner-Fairbank Highway Research Center's (TFHRC) Web site at www.tfhrc.gov, FHWA's Web site at www.fhwa.dot.gov, the National Transportation Library's Web site at http://ntl.bts.gov, or the OneDOT information network at http://dotlibrary.dot.gov.
Computer-Based Guidelines for Concrete Pavements, Volume I: Project Summary Publication No. FHWA-HRT-04-121
This report documents enhancements incorporated into the HIPERPAV® (HIgh PERformance PAVing) II software. The enhancements include the addition of two major modules: one to predict the performance of jointed plain concrete pavement (JPCP) as affected by early-age factors, and one to predict the early-age (first 72 hours) and early life (up to 1 year) behavior of continuously reinforced concrete pavement (CRCP). Two additional FHWA studies also were incorporated. One predicts dowel bearing stresses as a function of environmental loading during the early age, and the other involves optimizing concrete paving mixes as a function of 3-day strength, 28-day strength, and cost. The researchers also incorporated additional functionality into the software by reviewing and prioritizing feedback provided by users of the first generation of the software, HIPERPAV I.
To complete the project, the researchers conducted an extensive literature search on the mechanistic and mechanistic-empirical models that could be used for this purpose. They used a systems approach for incorporating additional developments in the software following the same methodology used during development of HIPERPAV I. A panel of technical experts helped evaluate the enhancements. Likewise, the model predictions were validated by employing existing databases and by investigating pavements during construction as well as those already in service.
This report summarizes the work conducted to enhance the HIPERPAV concrete pavement design guidelines. This is the first in a series of three volumes that document the tasks carried out to accomplish the objectives of this project.
The NTIS publication order number is PB2005-105417.
Computer-Based Guidelines for Concrete Pavements, Volume II: Design and Construction Guidelines and HIPERPAV II User's Manual Publication No. FHWA-HRT-04-122
This volume provides a comprehensive set of guidelines useful in designing and constructing both JPCP and CRCP. It also provides sample case studies that illustrate the proper use of HIPERPAV II to optimize the behavior of concrete pavements. Further, the document contains a user's manual for HIPERPAV II. This is the second volume in a series of three that documents the tasks carried out to accomplish the objectives of this project. The third document is Technical Appendices, Volume III (FHWA-HRT-04-127).
The NTIS publication order number for Volume II is PB2005-108228.
Field Observations and Evaluations Of Streambed Scour at Bridges Publication No. FHWA-RD-03-052
The variability and complexity of site conditions make it difficult to develop a methodology for predicting scour at bridges. Laboratory investigations often oversimplify or ignore many complexities common in the field. The U.S. Geological Survey, in cooperation with FHWA and many State highway agencies, has collected and compiled field data on scour at bridges at 79 sites in 17 States. Researchers analyzed the data to isolate pier, contraction, and abutment scour. The national database contains 493 local pier scour measurements, 18 contraction measurements, and 12 abutment measurements. The pier measurements were used to evaluate 26 published pier scour equations.
The Froehlich Design, HEC-18, HEC-18-K4, HEC-18-K4Mu, HEC-18-K4Mo (>2 millimeter), and Mississippi equations proved to be better than the other equations for predicting pier scour for design purposes. However, comparison of the scour predicted from these equations with the observed scour clearly shows that the equations do not account for the variability in the field data. Relations between dimensionless variables developed from laboratory experiments did not compare well with the field data. Analysis of the pier scour data indicated the importance of bed material characteristics as a variable in the predictive equations. A new K4 term for the HEC-18 pier scour equation was developed based on the relative bed material size (b/D50), where b = pier width and D50 is the median bed material.
A review of published literature revealed 29 references to abutment and contraction scour data; however, only a few provided complete datasets. Published comparisons of observed versus computed scour were inconclusive. A detailed comparison of computed contraction and abutment scour with field observations for two sites in Minnesota also was inconclusive. The current methodology for computing scour depth provides reasonable estimates of the maximum total scour, but the individual estimates of contraction and abutment scour did not compare well with the observed data. The accuracy of the contraction and abutment scour equations may depend on the degree of contraction, the flow distribution in and configuration of the approach, and how well the hydraulic model represents the true flow distribution.
The NTIS publication order number is PB2005-106540.
Freight Facts and Figures 2005
Publication No. FHWA-HOP-05-071
Freight Facts and Figures 2005 provides a snapshot of the volume and value of freight flows in the United States, the physical network over which freight moves, the economic conditions that generate freight movements, the industry that carries freight, and the safety, energy, and environmental effects of freight transportation. This snapshot helps planners, decisionmakers, and the public understand the magnitude and importance of freight transportation in the global economy. An electronic version of the publication is available at www.ops.fhwa.dot.gov/freight/.