Abstract:
The Falling weight deflectometer test (FWD) is a commonly used method for the evaluation of the structural performance of pavement systems. In the FWD test, a large weight is raised off the ground and dropped onto a rubber loading pad creating an impulse load representative of the real loading imposed by heavy traffic on the pavement. The excitation produced by the loading sets off waves in the pavement and underlying soil. Deflection time histories are gathered by an array of sensors placed at several nearby locations. The traditional method for interpreting the FWD data to backcalculate structural pavement properties, involves extracting the peak deflection from each displacement trace of the sensors (deflection basin) and matching it through an iterative optimization method to the deflections predicted by a static model of the pavement. This approach is computationally efficient; and when the depths of the layers are known, and their properties are largely homogeneous with depth, the procedure is effective in backcalculating layer properties. However, when the depths are uncertain or when the moduli vary within a layer, the static backcalculation scheme may not yield reliable results.The goal of this study is to investigate the feasibility and effectiveness of using the complete time history of the FWD test to overcome some of the limitations of the static backcalculation procedure, and recover pavement layer moduli distribution and thickness. The problem is also formulated as a numerical minimization problem, where the unknowns are the resilient moduli of thin "computational layers" that discretize the profile. Our initial finding is that this optimization formulation regularized by constraints on the magnitude and spatial gradient of the moduli, coupled with a continuation scheme for imposing the regularization terms, can overcome the ill-posedness nature or the original optimization problem. The computational effort for solving this inverse problem, however, is very significant as it requires repeated calls to the expensive forward problem: an elastodynamic simulation in stiff heterogeneous media. Additional work is needed to speed up the forward problem to be able to perform a more comprehensive evaluation with field data.

Authors:
Turkiyyah,G. M.

Keywords:
research, falling weight deflectometer, weight, evaluation, performance, pavement, systems, traffic, data, moduli, profile, speed

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/586.1.pdf http://wsdot.wa.gov/Research/Reports/500/586.1.htm

Abstract:
This research was Phase III of field investigations carried out over 12 years at a test section in southwest Washington State in an effort to quantify the contribution of geotextile separators to the long-term performance of pavement sections. Five different geotextile separators, as well as a control (soil-only) section, were installed in a test section covering two lanes with different base course thicknesses on a low volume but heavily loaded rural highway west of Bucoda, Wash. Phase I evaluated the performance of the separators during construction. Phases II and III were conducted to evaluate the performance of the separators 5 and 12 years after construction, respectively. Field and laboratory tests were conducted on the subgrade, granular base materials, and the geotextiles as part of the effort to correlate the performance of the pavement section to the presence of the geotextile separators. Falling weight deflectometer (FWD) testing was also performed at the site as part of the effort to quantify the performance of the pavement section. The laboratory tests indicated that the geotextiles successfully performed their separation function over the 12-year period. However, the soil-only sections had a minimal amount of intermixing at the base course/subgrade interface, indicating that the separation benefits of geotextiles may not be realized under relatively thick pavement sections. Field density tests indicated that the density of the subgrade in the sections with a geotextile generally increased between construction and the first field investigation, whereas the density of the soil-only sections remained about the same. Similarly, the FWD tests showed that the most significant increase in the subgrade moduli occurred in the first few months following construction. However, the soil-only sections exhibited behavior similar to the sections with geotextiles during the FWD testing, suggesting that for the relatively thick pavement sections, incorporation of geotextiles may not have provided a significant contribution to the overall performance of the section over the 12-year period. Some of the FWD results did suggest that geotextiles might contribute to an increase in the base course modulus over time.

Authors:
Collins,B. M., Holtz,R. D.

Keywords:
base, behavior, benefit, benefits, construction, control, density, falling weight deflectometer, field investigations, geotextile, geotextile separators, highway, materials, moduli, pavement, pavement performance, pavement section, research, rural, separators, subgrade, tests, volume, Washington, Washington state, weight, performance

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External Links: http://www.wsdot.wa.gov/research/reports/fullreports/595.1.pdf http://wsdot.wa.gov/Research/Reports/500/595.1.htm

Abstract:
This study describes the analysis of truck volume data collected by the Washington State Department of Transportation (WSDOT) over four and one half years, from 1988 through 1993. The primary objectives of this research were to: investigate the patterns in truck volumes at various locations in Washington State; determine whether seasonal factors can be developed and applied to short-duration truck volume measurements to better estimate average annual conditions; develop an easy procedure that other states can use to create their own seasonal factoring process, and produce a guidebook that explains this process and lists the necessary steps and concisely. This report summarizes all but the last of these objectives. This last objective is met in another summary report.

Authors:
Hallenbeck,M. E., Kim,S.

Keywords:
traffic surveillance and control, transport, weight, pavement management systems, truck counts, traffic counting

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Abstract:
Large trucks are often perceived to restrict the free flow of general traffic and present a safety hazard. In addition, the delay caused by trucks is thought to detrimentally affect the economy, and repetitive heavy loads increase pavement deterioration. Truck lane restrictions attempt to achieve one or more of four purposes: (1) improve highway operations, (2) improve the level of safety, (3) facilitate more even pavement wear, and (4) ensure better operation and safety through construction zones. Three study sites and a control site were selected in Puget Sound region to test the effectiveness of truck lane restrictions in achieving these purposes. Three types of analysis were performed: (1) an in-depth analysis to determine how the implementation of a lane restriction would impact the operation, safety, and life of the facility and the economic impacts for the region, (2) a site comparison analysis to determine whether the results from the in-depth analysis could confidently be applied to other areas in the region, and (3) a survey analysis to determine the opinions of truckers, motorists, industry, and enforcement officials with respect to lane restrictions. At this time, truck lane restrictions are not recommended for further implementation in the Puget Sound region. This recommendation is based on (1) a lack of obvious operation, safety-related, economic, or pavement related benefits, (2) lack of consistency between the sites, and (3) some noted resistance to lane restrictions from the motor carrier industry.

Authors:
Mannering,F. L., Loehne,J. L., Araucto,J.

Keywords:
transport, weight, large truck, lane restrictions, route restrictions, time-of-day restrictions, speed restrictions, operational impacts, safety impacts

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Abstract:
This is the second report for an FHWA sponsored project that is investigating the barriers to implementing IVHS commercial vehicle operations (CVO) technologies in seven northwestern states. This report describes the barriers to implementing the IVHS CVO technologies and the steps needed to surmount those barriers. The report is intended to serve as a blueprint for state agency efforts to use to successfully and incrementally improve the efficiency with which they regulate trucking industry operations.The project team concludes that the primary barriers to implementation of IVHS CVO technologies are neither institutional nor regulatory. Instead, the barriers are a combination of economic uncertainty and a lack of shared vision among the various states, state agencies, and trucking industry groups. Although institutional and regulatory barriers exist in the seven participating states, these barriers are relatively unimportant in comparison to the barriers that arise from disagreements over the system's intended functions, the cost of providing the system, and the parties responsible for paying those costs.The project team has reached the conclusion that the only way to surmount the barriers produced by the above conditions is to create a modular system that will allow both states and private companies to enter into the IVHS CVO process for little cost. 'Me system will have to be expandable to allow its capabilities to grow as the benefits from IVHS CVO technologies become more apparent and as funding becomes available. The initial system must be simple, low cost (for both states and trucking firms), relatively easy to implement, and flexible enough to meet the needs of different states and state agencies. Finally, benefits commensurate with the costs of participating in the system must be available to all involved agencies and trucking firms.

Authors:
Hallenbeck,M. E., Koehne,J., Scheibe,R. R., Rose,D., Leech,J.

Keywords:
transport, weight, truck, weights, borders

Abstract:
This is the second report for an FHWA sponsored project that is investigating the barriers to implementing IVHS commercial vehicle operations (CVO) technologies in seven northwestern states. This report describes the barriers to implementing the IVHS CVO technologies and the steps needed to surmount those barriers. The report is intended to serve as a blueprint for state agency efforts to use to successfully and incrementally improve the efficiency with which they regulate trucking industry operations.The project team concludes that the primary barriers to implementation of IVHS CVO technologies are neither institutional nor regulatory. Instead, the barriers are a combination of economic uncertainty and a lack of shared vision among the various states, state agencies, and trucking industry groups. Although institutional and regulatory barriers exist in the seven participating states, these barriers are relatively unimportant in comparison to the barriers that arise from disagreements over the system's intended functions, the cost of providing the system, and the parties responsible for paying those costs.The project team has reached the conclusion that the only way to surmount the barriers produced by the above conditions is to create a modular system that will allow both states and private companies to enter into the IVHS CVO process for little cost. 'Me system will have to be expandable to allow its capabilities to grow as the benefits from IVHS CVO technologies become more apparent and as funding becomes available. The initial system must be simple, low cost (for both states and trucking firms), relatively easy to implement, and flexible enough to meet the needs of different states and state agencies. Finally, benefits commensurate with the costs of participating in the system must be available to all involved agencies and trucking firms.

Authors:
Hallenbeck,M. E., Koehne,J., Scheibe,R. R., Rose,D., Leech,J.

Keywords:
transport, weight, truck, weights barriers

Abstract:
This is the second report for an FHWA sponsored project that is investigating the barriers to implementing IVHS commercial vehicle operations (CVO) technologies in seven northwestern states. This report describes the barriers to implementing the IVHS CVO technologies and the steps needed to surmount those barriers. The report is intended to serve as a blueprint for state agency efforts to use to successfully and incrementally improve the efficiency with which they regulate trucking industry operations.The project team concludes that the primary barriers to implementation of IVHS CVO technologies are neither institutional nor regulatory. Instead, the barriers are a combination of economic uncertainty and a lack of shared vision among the various states, state agencies, and trucking industry groups. Although institutional and regulatory barriers exist in the seven participating states, these barriers are relatively unimportant in comparison to the barriers that arise from disagreements over the system's intended functions, the cost of providing the system, and the parties responsible for paying those costs.The project team has reached the conclusion that the only way to surmount the barriers produced by the above conditions is to create a modular system that will allow both states and private companies to enter into the IVHS CVO process for little cost. 'Me system will have to be expandable to allow its capabilities to grow as the benefits from IVHS CVO technologies become more apparent and as funding becomes available. The initial system must be simple, low cost (for both states and trucking firms), relatively easy to implement, and flexible enough to meet the needs of different states and state agencies. Finally, benefits commensurate with the costs of participating in the system must be available to all involved agencies and trucking firms.

Authors:
Hallenbeck,M. E., Koehne,J., Scheibe,R. R., Rose,D., Leech,J.

Keywords:
transport, weight, truck, weights

Abstract:
This report outlines the Washington State Department of Transportation's truck weight data needs and the potential plans that might be used to meet those needs. It summarizes the requirements of HELP, SHRP, the Traffic Monitoring Guide, and special state needs, and recommends alternative plans for purchasing and deploying weigh-in-motion equipment within the state.

Authors:
Hallenbeck,M. E.

Keywords:
transport, weight, weigh-in-motion, WIM, traffic data collection, weight monitoring, SHRP data collection, program

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Abstract:


Authors:
Hallenbeck,M. E.

Keywords:
transport, weight

Abstract:
As part of the pooled fund research project, the Washington State Department of Transportation was selected to field-test approximately 100 tons of Calcium Magnesium Acetate (CMA) to evaluate its potential as a deicing chemical with direct comparison to salt (Sodium Chloride) and Urea. Evaluation included all aspects of storage, handling, use, and performance. CMA was applied whenever necessary at each test site, using the same application rates as presently used for salt. Typical equipment consisted of front dump trucks with the spinner ahead of the rear axle, and rear discharge hopper trucks. All equipment was used without modification.The use of CMA at the beginning of a storm reduced the amount of bonding of snow to the roadway surface. This effect of keeping the roadway surface bare for longer periods of time reduced the cost of snow fighting. This was accomplished with chemical application rate of 125 Ibs. per lane mile.The addition of sand to CMA reduced the problems of dust, caking and uneven distribution. The sand provided moisture and weight to the application resulting in a smoother, more even distribution. CMA spread above was excessively dusty creating problems in the spreading and distribution. CMA is slower to react on compact snow and ice than salt or Urea. This delay in reaction time was not considered a handicap in the overall snow fighting procedure.The conclusion was that CMA shows promise as a deicing-melting chemical. The problems of dust, light-weight and brittleness need further work and may be significantly alleviated by development of a hydrated compound.

Authors:
Ernst,D. D.

Keywords:
Alternative, axle, chloride, cost, Deicing (CMA Research), development, evaluation, field test, ITS, lightweight, performance, research, roadway, salt, snow, transportation, truck, trucks, Washington, Washington state, weight

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Abstract:
This report documents the testing of a piezo-electric cable weigh-in-motion (WIM) truck scale. The equipment tested was developed by the French national laboratory, Laboratorie Central des Ponts et Chausees. Tests were made on the accuracy of the system's static weight estimates, its estimates of vehicle speed, and its classification of vehicles. Speed and vehicle classification estimates were quite good. Weight estimates did not meet the proposed HELP system specifications. The standard deviation of the difference between WIM and static gross vehicle weights was approximately 20 percent. Tests were also performed to examine the effects of tire pressure, speed and lane position on the voltage output of the cable. Of these variables, tire pressure was determined to most highly effect cable voltage output. Reduction of tire pressures from 105 psi to 75 psi had a statistically significant effect on cable voltage output.

Authors:
Hallenbeck,M. E., Hawkins,N. M., Chang,J.

Keywords:
transport, weight, weigh-in-motion, truck scales, piezo-electric

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Abstract:
NOT PRINTED This report documents Washington state's experiences with the FHWA's bridge weigh-in-motion system. The system was tested on four concrete bridges (one arched slab, one box girder and two pre-tensioned concrete girders) with moderate to heavy traffic volumes. The system gave reasonable axle and gross vehicle weights under ideal conditions, but showed major limitations under high volumes. Over the life of the project, mean gross vehicle weight errors for individual trucks ranged between 11 and 18 percent with tandem and single axle weights having high mean errors. Errors for mean population gross vehicle weight estimates averaged two percent.

Authors:
Hallenbeck,M. E.

Keywords:
transport, weight, truck

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Abstract:
This study involved an in-depth evaluation of the Washington State Department of Transportation highway data development and analysis activities. It developed statistically-based procedures and recommendations for a streamlined highway data collection program. Opportunities to reduce manpower and equipment costs, streamline work activities, improve the quality of data collection and provide accurate and timely data for the various users were identified. Given the focus on highway data, the major effort was devoted to the Department's traffic counting program. However, many data items and programs were considered, with the following receiving particular attention: traffic volume counting, including estimation of annual average daily traffic at any location throughout the state highway system; associated seasonal, axle and growth factors; vehicle classification; truck weights; and the relationship between the statistical sampling requirements recommended for these items and those associated with the FHWA Highway Performance Monitoring System in the state.

Authors:
Ritchie,S. G., Hallenbeck,M. E.

Keywords:
analysis, Annual, axle, cost, costs, data, data collection, developed, development, equipment, evaluation, highway, monitoring, performance, performance monitoring, program, quality, sampling, seasonal, Study, System, traffic, traffic counting, transportation, truck, vehicle classification, volume, Washington, Washington state, weight, weights

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Abstract:


Authors:
Hallenbeck,M. E., Hooks,J.

Keywords:
transport, weight, weigh-in-motion, bridge

Abstract:
This report describes the techniques used to evaluate the effects of various axle configurations with dual and single tires on pavement performance and the current State of Washington Regulation RCW 46.44.042. Equivalent wheel load factors were developed for various widths of single tires on both rigid and flexible pavements. Single tires with widths 10 to 18 inches were analyzed and it was found that by equivalent axle loads the predicted damage to pavements was greater for axles with single tires that those with dual tires. To verify the theoretical analyses, two field experiments were conducted. First, extensometers were placed in the outer wheel path of the pavement ramp at the Fife I-5 weigh station. Truck induced pavement surface deflections were measured after the vehicles were weighed on the scale. A comparison of measured and calculated deflections revealed good agreement thus in part verifying the theoretically based calculations. Second, a field site near Edmondton, Alberta was also used in the verification process by use of the WSDOT Falling Weight Deflectometer. Again the theoretical approach was further verified.

Authors:
Mahoney,J. P., Sharma,J.

Keywords:
pavement management, transport, weight, evaluation, regulation, tire

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Abstract:
The Motor Carrier Act of 1980 and the Staggers Act of 1980 have partially set aside decades of rigid regulations of interstate freight movement. These actions have the potential to bring forth significant changes to the networks of interstate freight transportation. The object of this research was to ascertain the impacts of deregulation of the Washington State transportation system. Information was obtained by surveying and interviewing shippers and freight transportation providers throughout the state. Anticipated impacts, e.g. accelerated rail abandonment or lost of motor carrier service to small communities were not present. The study reflects a relative increase in truck service and decrease in rail service since deregulation. Indications are this may be further amplified in certain regions of the state. The study recommends that potential highway impacts be incorporated into pavement management systems. Transportation officials are enjoined to treat issues relative to truck size and weight, highway cost allocation and deregulation as a single issue. Also, the Local Rail Service Assistance Program should be considered for use to offset any adverse impacts resulting from deregulation. During this period of the study, general economic conditions were poor. This resulted in a decrease in freight shipments and would suggest that some impacts of deregulation have been suppressed.

Authors:
Public Transportation and Planning Division, Washington State Department of Transportation

Keywords:
condition, cost, Deregulation, freight, highway, highway impacts, impact, impacts, management, management system, management systems, motor carrier, networks, pavement, pavement management, pavement management systems, program, rail service, railroads, regulation, research, System, systems, transportation, truck, trucking, trucks, Washington, Washington state, weight

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Abstract:
This report summarizes the placement and performance of sulfur extended asphalt (SEA) paving mixtures at a highway test site (SR 270) near Pullman, Washington. The report includes a summary of the mixture and structure designs and construction details. This is followed by a discussion of the data collection and analysis accomplished over a three year evaluation period (1979 - 1982). A major experimental feature of the study was the use of 0/100 (conventional asphalt concrete), 30/70 and 40/60 SEA binder ratios (sulfur/asphalt ratios are expressed as weight percents) in the experimental paving mixtures.

Authors:
Mahoney,J. P.

Keywords:
analysis, asphalt, asphalt concrete, asphalt pavement, concrete, construction, data, data collection, data collection and analysis, design, evaluation, experimental, extended asphalt, highway, mixture, pavement, pavement performance, performance, Study, sulfur, Washington, weight

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Abstract:
This study was made to obtain information on the noise levels being emitted by vehicles currently using the highways of the State of Washington. The Washington State Highway Commission requested this study for guidance in proposing vehicle noise control legislation. The main controversy in states with existing comprehensive vehicle noise legislation has concerned trucks traveling on roads with posted speeds above 35 mph. The main thrust of our study is therefore concerned with this particular area, although data were also taken on automobiles and on roads posted at less than 35 mph. This study is unique in that the noise level - and the speed of all vehicles were measured. In addition, all trucks over 10,000 lb were weighed. Our large body of data has been graphed in numerous ways to illustrate various aspects--including how the noise factor varies with speed, weight, and percentage of full load, etc. Some photographs of the trucks together with their noise data a real so included.

Authors:
Foss,Rene N.

Keywords:
control, data, highway, Highways, noise, Noise Levels, speed, Study, truck, trucks, vehicle noise, Washington, Washington state, weight

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