When I survey civil and structural engineers about the information they desire in a professional magazine like Rebuilding America’s Infrastructure, the same response tops the list every time: research news.

While engineers crave this information, it is difficult for them to keep up — the industry is long on “information,” but the professionals who process it are short on time.

This imbalance initiated the concept for this month’s RAI Exclusive. I scoured the extensive journal databases of the Transportation Research Board (TRB) and the American Society of Civil Engineers (ASCE) to find recent impactful whitepapers about topics related to engineering for bridges and roads. Just reading the abstracts will apprise you of recent findings. However, if you are interested in reading any of these papers in full, you’ll find links for each. (Note: You’ll be required to pay any necessary fees charged by the TRB or ASCE to download these articles.)

General
Practical Solution Concepts for Planning and Designing Roadways
Journal: ASCE Journal of Transportation Engineering, Volume 136, Issue 4, pages 291-297

Authors: Nikiforos Stamatiadis, P.E., University of Kentucky; and Adam Kirk, P.E., AICP, Don Hartman, and Jerry Pigman, P.E., Kentucky Transportation Center

Date: April 2010

Abstract: Developing a procedure that yields up to the maximum margin of return for the investment requires an approach that takes into account specific safety issues and the commensurate design elements for each roadway. Kentucky’s highway agency has embarked upon an initiative tagged “practical solutions,” which sets its goal toward reducing costs throughout the project development process extended into operations and maintenance of all highway facilities. The system-based evaluation of practical design in this study examined the safety and operational performance of various cross-section alternatives, based on highway capacity and highway safety manual procedures. Alternative cross sections ranged from an improved two-lane section representing a practical solution approach to a four-lane-divided highway. A case study of a Kentucky intersection improvement project is presented that exemplifies a practical solution.

Bridges
Use of Precast Bridge Members in Areas of High or Moderate Seismicity
Journal: Transportation Research Record: Journal of the TRB, No. 2131, pages 101-109

Authors: Jugesh Kapur and Bijan Khaleghi, Washington State Department of Transportation, Bridge and Structures Office

Date: January 2010

Abstract: Prefabricated bridge components are in increasing demand for accelerated bridge construction. Precasting eliminates the need for forming, casting, and curing concrete in work zones and makes bridge construction safer while improving quality and durability. Precast bridges consisting of pre-tensioned girders, post-tensioned spliced girders, trapezoidal open box girders, and other types of superstructure members are often used for accelerated bridge construction; however, bridge engineers are concerned with the durability and performance of bridges made of precast members in areas of high or moderate seismicity. The applicability of the American Association of State Highway and Transportation Officials load and resistance factor design specifications to precast prefabricated bridges in areas of high or moderate seismicity was examined. The different seismic design methodologies were reviewed and guidance in their application to precast bridges is provided.

High-Performance Aesthetic Bridge Rail and Median Barrier
Journal: Transportation Research Record: Journal of the TRB, No. 2120, pages 60-73

Authors: Karla A. Lechtenberg, Robert W. Bielenberg, Scott K. Rosenbaugh, Ronald K. Faller, and Dean L. Sicking, University of Nebraska-Lincoln

Date: December 2009

Abstract: Design of high-performance concrete barriers for heavy vehicles has advanced little in recent years. Barrier improvements were needed in terms of design aesthetics, safety performance, and economy. Advancement was deemed necessary for improved barrier geometry design to reduce vehicle instability and the potential for occupant head slap on the barrier, improved understanding of impact loads for heavy vehicles and use of these loads to optimize barriers, and improved barrier aesthetics. This paper describes the development of two National Cooperative Highway Research Program (NCHRP) Report 350 Test Level 5 (TL-5) barriers that address these needed advancements. The open concrete bridge rail and the concrete median barrier were successfully full-scale crash-tested according to the TL-5 safety requirements set forth in NCHRP Report 350. These designs represent a major advancement in the safety and economy of high-performance concrete barriers.

Traffic analysis
Field Evaluation of Model-Based Estimation of Arterial Link Travel Times
Journal: Transportation Research Record: Journal of the Transportation Research Board, No. 2130, pages 149-157

Authors: Hui Xiong and Gary A. Davis, University of Minnesota

Date: January 2010

Abstract: In many urban areas there is increased interest in using travel time and its reliability to assess the level of service provided by surface transportation. This is straightforward on urban freeways with extensive systems of location-based sensors but becomes problematic off the freeways. Traffic volume and flow, collected by permanent and portable traffic counters, are arguably the measures of traffic conditions most commonly available on arterials. These could become a useful part of a travel time monitoring system if they could be converted to plausible estimates of travel time. The objective of this study is to compare several travel time estimation models given different data availability scenarios and to identify the most appropriate one to support estimation of network-wide arterial travel times. It was found that (a) when the site-specific running time is known but the signal timing is not available, the four models produced similar mean absolute percentage errors (MAPEs) from 14.7 percent to 17.4 percent and (b) the Singapore and Skabardonis-Dowling models, using maximal site-specific information, produced MAPE values of 6.9 percent and 6.3 percent, respectively. Using the Skabardonis-Dowling model is suggested because of its flexibility in accommodating data availability conditions and because it tended to have the smallest MAPE values in most data availability scenarios.

Pavement/Asset management
Assessing the Agreement among Pavement Condition Indices
Journal: ASCE Journal of Transportation Engineering, posted online ahead of print

Authors: Nasir G. Gharaibeh, Yajie Zou, and Siamak Saliminejad, Texas A&M University

Date: December 2009

Abstract: Pavement condition indices are numerical indicators of the structural and material integrity of pavement. Because these indices appear to be similar (essentially a 0–100 scale, with 100 indicating excellent condition), it can be tempting to use different indices for comparing the performance of pavement networks in different states or jurisdictions within a state. To ascertain the level of agreement among these condition indices, six pavement condition indices from five departments of transportation in the United States are discussed and compared using distress and ride quality data … The results provide empirical evidence that there are significant differences among seemingly similar pavement condition indices.

Integration of GIS and Data Mining Technology to Enhance the Pavement Management Decision Making
Journal: ASCE Journal of Transportation Engineering, Volume 136, Issue 4, pages 332-341

Authors: Guoqing Zhou and Scott Reichle, Old Dominion University; Linbing Wang and Dong Wang, Virginia Tech Transportation Institute, Virginia Polytechnic Institute and State University

Date: April 2010

Abstract: This paper presents a research effort undertaken to explore the applicability of data mining and knowledge discovery (DMKD) in combination with Geographic Information System (GIS) technology to pavement management to better decide maintenance strategies, set rehabilitation priorities, and make investment decisions. The main objective of the research is to utilize data mining techniques to find pertinent information hidden within the pavement database. Mining algorithm C5.0, including decision trees and association rules, has been used in this analysis. The selected rules have been used to predict the maintenance and rehabilitation strategy of road segments. A pavement database covering four counties within the state of North Carolina, which was provided by North Carolina Department of Transportation (NCDOT), was used to test this method. From the experimental results, it was found that the rehabilitation strategy derived by this paper is different from that proposed by the NCDOT. With the pilot experiment in the project, it can be concluded: (1) use of the DMKD method for the decision of road maintenance and rehabilitation can greatly increase the speed of decision making, thus largely saving time and money, and shortening the project period; (2) the DMKD technology can make consistent decisions about road maintenance and rehabilitation if the road conditions are similar, i.e., interference from human factors is less significant; (3) integration of the DMKD and GIS technologies provides a pavement management system with the capabilities to display treatment decisions against distresses graphically; and (4) the decisions related to pavement rehabilitation made by the DMKD technology is not completely consistent with that made by ITRE, thereby, the postprocessing for verification and refinement is necessary.

Estimation of Remaining Service Life of Flexible Pavements from Surface Deflections
Journal: ASCE Journal of Transportation Engineering, Volume 136, Issue 4, pages 342-352

Authors: Daba S. Gedafa, Ph.D., M.ASCE, and Mustaque Hossain, Ph.D., P.E., F.ASCE, Kansas State University; Richard Miller, P.E., M.ASCE, Kansas Dept. of Transportation, Materials and Research Center; and Thomas Van, P.E., FHWA-Office of Asset Management

Date: April 2010

Abstract: Remaining service life (RSL) has been defined as the anticipated number of years that a pavement will be functionally and structurally acceptable with only routine maintenance. Usually, RSL is computed from pavement condition survey results. This paper presents a methodology for estimating RSL from pavement surface deflections. Deflection data were collected with a Dynatest 8000 falling weight deflectometer (FWD) from 1998 to 2006. … The results showed that a sigmoidal relationship exists between RSL and center (FWD first sensor) deflection. Sigmoidal RSL models have very good fits and can be used to predict RSL at the network level based on the center deflection from FWD.

Retaining walls
Exhumed Geogrid-Reinforced Retaining Wall
Journal: ASCE Journal of Geotechnical and Geoenvironmental Engineering, posted online ahead of print

Authors: Dov Leshchinsky and Christopher L. Meehan, University of Delaware; Baris Imamoglu, Michael Baker Jr.

Date: March 2010

Abstract: An instrumented geogrid-reinforced wall constructed on a highly compressible foundation was deconstructed 16 months after its completion, providing a unique opportunity to exhume and examine the instrumented geogrids that were used to construct the wall. The objectives of this post mortem study were: (1) to inspect the condition of the strain gages that were attached to the geogrid layers before construction and to verify the reliability of their output, (2) to develop a procedure in which the residual (plastic) strains along exhumed geogrid panels could be determined, and (3) to assess the in-situ strain and force distribution along geogrid panels based on the measured residual strains from the exhumed geogrids. … Findings imply that if the same type of reinforcement had been used throughout the height of the wall, the mobilized force along the height would have been relatively uniform. The back-calculated maximum force in the geogrids indicated that the factor of safety on the long-term strengths of the geogrids ranged from about 1.4 on the stronger/stiffer geogrid to about 1.8 on the weaker/softer geogrid.

Conclusion
Special thanks to ASCE and TRB for working with us to connect our readers with the happenings in the technical journal genre of the industry. In January 2009, the ASCE began publishing accepted journal manuscripts online in advance of scheduled print publication. You can find all ASCE journal articles listed here, as well as thousands of others, using the links provided, or by visiting the ASCE publications website.

This article also provides links to all TRB articles. Note that abstracts and summaries of the TRB articles are provided here with permission: Copyright, National Academy of Sciences; used and adapted with permission of the Transportation Research Board. For complete TRB papers, as well as its vast library of guidelines, special reports, and ongoing research news, visit http://pubsindex.trb.org.