bluuebunny/crossref_metadata_2025 huggingface dataset:
Predesign Foundation Load Test Program for US-17 (Wilmington) Bypass over Northeast Cape Fear River
Authors: Hidden Scott , Abar Nariman
Published: April 2007

The North Carolina Department of Transportation is currently conducting a predesign foundation load test for a new bridge over the Northeast Cape Fear River near Wilmington, North Carolina. The primary purpose of the load test program is to determine whether concrete piles can penetrate a very dense and cemented sand layer and what side friction and tip bearing capacities should be used for the design of the drilled piers. Significant cost savings could be realized if pile foundations instead of drilled piers could support the approach spans of the bridge. For this determination, three concrete piles will be installed 30 m into the ground. Significant cost savings could also be realized by making a more accurate determination of the drilled pier capacities. For this determination, the side friction and tip bearing capacities of the dense Peedee sands and the underlying hard marine clays will be determined with Osterberg cell tests on two 2130-mm-diameter drilled piers. The different subsurface layers (muck, alluvial sands, and Peedee sands) will also be tested laterally with both static and statnamic testing to assist in the foundation design. The load test program incorporates an NCHRP research program on pile groups. The program includes testing a reusable instrumented steel pile group and frame at various sites in various soil conditions around the United States. The load test program results to date, the effect of the results on the foundation design, and the construction, testing, and instrumentation of the drilled piers are described.
Evaluation of Compaction Methods for Pipe Trench Backfill in Areas of High Water Table
Authors: Ahmad Irtishad , Putcha Sastry
Published: April 2007

Determining the density of backfill material and attaining the desired degree of compaction in the backfill under a high water table, typical operations in South Florida, present a difficult problem to the Florida Department of Transportation (FDOT) engineers and contractors. As a first step in seeking the solution to this problem, variations in soil conditions, determined by standard penetration test (SPT) N-values, that corresponded with varying methods of compaction were evaluated. In the experimental phase of the project, five field conditions were tested: Condition A, control dry, backfilling in the dry condition above water; Condition B, dump soil, no compaction, backfilling under the water table, no tamping; Condition C, dump soil, compact per FDOT specifications, no dewatering, backfilling under the water table, tamping with a 2 by 4 as specified; Condition D, control wet, compact per FDOT specifications, dewatering during pipe installation and backfilling with periodic compaction according to FDOT specifications; and Condition E, dump soil, no compaction, dewatering during pipe installation and backfilling by dumping. For each of the five field conditions, SPT N-values were obtained at seven locations. As expected, the highest N-values were obtained for the control dry condition (Field Condition A). The next best set of N-values was obtained for the control wet condition (Field Condition D). This result was also expected. In Field Condition B, backfill was dumped without tamping. In Field Condition C, backfill was compacted by hand tamping in accordance with FDOT specifications (Section 125-8.3.3, 1996). It was evident from the SPT values that the result did not noticeably improve from Condition B to Condition C. In Condition E, dewatering was continued after the pipe segments had been placed and bedded. Lifts of backfill material were dumped without compacting or tamping. The N-values obtained from Field Condition E were not significantly different from the values obtained for either Condition B or C. The provision of hand tamping in the FDOT specifications is questioned as a result of these findings, and the benefit of dewatering, although obvious, is substantiated.
Long-Term Durability Study: Long-Span Structures
Authors: Hensley Scott I. , Perry Phil
Published: April 2007

Well over 2,000 long-span structural plate structures have been constructed in the United States over the past 25 years, both as grade-separation structures and culverts. Long-span structural plate structures are short-span bridges defined in the AASHTO Standard Specifications for Highway Bridges, Section 12, as structural plate structures (pipe, pipe-arch, and arch) that exceed the maximum sizes imposed by Article 12.6 on flexibility factor limits. Both applications have the potential to subject the long-span structure to corrosive action from runoff and deicing chemicals and also to abrasion from an abrasive bedload. In an effort to ensure that current design methods incorporate proper protection, if required, 21 long-span structures were inspected and rated in terms of condition with regard to the effects of corrosion and abrasion. Core samples were extracted from each structure and analyzed for metal loss. Samples of runoff and backfill were also taken and analyzed for pH, resistivity, and chloride content. Given this information, structure performance was compared with accepted methods of projecting metal loss in corrugated steel drainage structures.
Long-Span Deep-Corrugated Structural Plate Arches with Encased-Concrete Composite Ribs
Authors: Morrison Timothy D.
Published: April 2007

The design and construction of two long-span reinforced deep-corrugated structural plate arch culverts are described. The arch structures have maximum spans of 23.3 and 19.0 m. They were constructed on the Alaska Highway in northern British Columbia, Canada, during the fall of 1998. The 23.3-m-span arch is the largest of its kind in the world. Both structures are intermittently reinforced using a system of encased-concrete stiffeners. This system employs concrete pumped into the cavities formed by opposing deep-corrugated steel plates fitted with shear studs. The reinforcement for the 19.0-m structure was terminated at a location above the springline of the arch. The reinforcement for the 23.3-m-span arch extended to the top of the foundation. The arches were designed in accordance with the provisions of the Ontario Highway Bridge Design Code and the new Canadian Highway Bridge Design Code for Buried Structures. They were also reviewed using a nonlinear frame analysis (Structural Optimization Design and Analysis, or SODA) and a finite-element analysis (Nonlinear Soil-Structure Interaction Program, or NLSSIP). The deflected shapes of the two arches were monitored by instruments in the field during the construction and backfilling operation. The design results and field-measured deflections are evaluated.
Effects of Fiber Reinforcement on Strength and Volume Change in Expansive Soils
Authors: Puppala Anand J. , Musenda Chisha
Published: April 2007

The results of a research study to investigate the influence of discrete and randomly oriented polypropylene fiber reinforcement on expansive soil stabilization are presented. Two expansive soils were used as control soils in the testing program. Two types of fibers and four fiber dosages (0,0.3,0.6, and 0.9 percent by dry weight of soil) were considered. Both raw and fiber-reinforced clayey samples were prepared and subjected to unconfined compressive strength (UCS), volumetric shrinkage, three-dimensional free swell, and swell pressure tests. Test results were statistically analyzed to investigate the effectiveness of fiber reinforcement on strength, swell, and shrinkage characteristics of expansive clays. Results indicated that the fiber reinforcement enhanced the UCS of the soil and reduced both volumetric shrinkage strains and swell pressures of the expansive clays. The fiber treatment also increased the free swell potential of the soils. Practical implications of the findings and future research directions are discussed.
Acceleration Characteristics of Starting Vehicles
Authors: Long Gary
Published: April 2007

Acceleration characteristics of starting vehicles are needed for many transportation analysis and design purposes involving driveways, turning bays, intersecting streets, traffic signals, railroad crossings, simulation software, and so forth. Constant acceleration is sometimes assumed, or AASHTO Green Book values based on piecewise-constant accelerations are sometimes adopted. However, continuing research has shown that linearly decreasing acceleration rates better represent both maximum vehicle acceleration capabilities and actual motorist behavior. It is not acceleration that usually is constant during speed changes; it is the rate of change in acceleration. The evolution of AASHTO acceleration values for design is traced, and the literature is reviewed for pertinent field observations. Linearly decreasing acceleration (and some deceleration) model parameters are calibrated for various sets of observational and design data. Despite published results from thousands of field measurements, the values selected for design were found to be based mostly on vehicle performance capabilities, with conjecture about how many of these capabilities are normally used by drivers. Design accelerations were found to deviate substantially from observed accelerations. At the start of motion, observed accelerations were about 15 percent faster for passenger cars and 45 percent faster for SU (single unit) trucks than design accelerations. As speed increased, observed accelerations dropped three to four times faster than design accelerations for these vehicles. Observed accelerations for WB-15 trucks began 40 percent to 75 percent slower than design accelerations, and they were considerably slower than the values in the Green Book for trucks at railroad crossings. Voids in the available information base are identified. Linearly decreasing design acceleration rates for motorists operating different classes of vehicles in different design situations are recommended, and revisions for Green Book parameters and charts are suggested. The recommended acceleration model greatly simplifies acceleration parameters but implies using different acceleration relationships for different design speeds instead of one for all.
To LDT or Not to LDT: Assessment of Principal Impacts of Light-Duty Trucks
Authors: Maria Kockelman Kara
Published: April 2007

Light-duty truck classification allows manufacturers and owners to avoid a host of passenger-car regulations, including gas-guzzler taxes, safety standards, and more stringent emissions and fuel-economy standards. The distinct policies that govern light-duty trucks and passenger cars are described; the emissions, safety, and fuel economy differences that have resulted are evaluated; and the household use differences across such vehicles are investigated. The result is that when the average new pickup truck or sport-utility vehicle is compared with a passenger car, there appears to be an implicit subsidy of roughly $4,400 favoring the light-duty truck. When minivans are compared with passenger cars, this subsidy is estimated to be around $2,800. With more equitable vehicle regulations, it is likely that prices would more accurately reflect the true cost differences resulting from the use of these vehicles, causing light-duty trucks to lose some of their popularity or clean up their act.
Carbon Dioxide Emissions from World Passenger Transport: Reduction Options
Authors: Schafer Andreas
Published: April 2007

Today, passenger transport worldwide is responsible for almost 15 percent of anthropogenic energy-related emissions of carbon dioxide (CO2), the most abundant greenhouse gas. If the strong forces that generate travel demand and concomitant greenhouse gas emissions continue, world passenger traffic volume may rise more than fourfold over the 1990 level by 2050. During the same period, carbon dioxide emissions due to passenger transport are expected to multiply by a factor of more than 3, ultimately accounting for 2.7 billion tons of carbon in 2050. Based on these projections, the present study evaluates a range of emission-reduction options. Among these, technological measures offer the greatest potential and are key to drastically reducing carbon dioxide emissions. Radical fuel efficiency improvements in the world’s automobile fleet—along with continuations of past trends in the energy intensity of other passenger transport modes—could curtail the projected 2050 baseline emissions level by about 40 percent. Simultaneous substitution of oil products by natural gas could reduce CO2 emissions by another 25 percent and ultimately lead to emission stabilization at 1.2 billion tons of carbon in 2050; any further significant reduction in CO2 emissions would require the largescale introduction of zero-carbon fuels. Although the CO2-reduction potential of transportation systems management measures is comparatively limited, such measures are needed to abate other transport sector externalities such as accidents, noise, and traffic congestion.
Land Use as an Air Quality Control Measure: Review of Current Practice and Examination of Policy Options
Authors: Ang-Olson Jeffrey , Fischer Michael , Dulla Robert
Published: April 2007

The inclusion of sustainable land use policies and programs for emissions credit in the air quality planning process is examined. Reviewed first is the role of land use in procedures for development of the state implementation plan (SIP) and the transportation conformity determination. Twenty-seven metropolitan areas were surveyed to identify how land use currently is incorporated into air quality plans. The survey found nine metropolitan areas that include a control measure involving land use in an air quality plan, though only two of these actually quantify an emission reduction from the measure. Then three general policy options are examined that could allow for better accounting of the air quality benefits of sustainable land use. One option is to enhance transportation and land use forecasting procedures so that they better capture land use and design features. A second option is to adopt land use policies as an explicit SIP control measure. A third option is to show an emissions reduction from land use as part of a transportation plan conformity determination. Existing rules are reviewed concerning each of these options, and how they would apply to land use measures is discussed.
Toward a Strategic Plan for Transportation—Air Quality Research, 2000-2010
Authors: Savonis Michael J.
Published: April 2007

The challenge of jointly addressing transportation and air quality concerns has been the subject of research for some time, but it reached its apex after passage of the Clean Air Act Amendments of 1990 and the Intermodal Surface Transportation Efficiency Act of 1991. Since that time, the legislative and regulatory context that prompted extensive research has been in continual flux, leading to ever-new areas even as the original agenda set in the early 1990s has yet to be completed. Critical relationships between transportation behavior and air quality impacts have yet to be clarified, and more data and better analytical tools will be necessary before greater understanding is achieved. The advent of new strategies related to telecommuting, e-commerce, vehicle insurance, car sharing, and “sustainability” poses serious questions for the research community. Concurrently, new challenges abound spawned from current and future developments. New air quality standards have redefined the meaning of “clean” air. Air toxics loom as the next focus area from the 1990 amendments. New vehicle and fuel standards are being adopted. Greenhouse gases and global warming pose particular challenges for transportation, but radically new vehicle-fuel systems for cars, trucks, and buses show promise that the transportation community can again rise to meet these challenges. Knowing where the greatest air quality problems exist and how best to address them is the stuff of cutting-edge research, which will pose a challenge into the next decade. It is an exciting time to be in transportation and air quality.
Alternatives to Diesel Fuel in California: Fuel-Cycle Energy and Emission Effects of Possible Replacements due to the Toxic Air Contaminant Diesel Particulate Decision
Authors: Saricks Christopher L. , Rote Donald M. , Stodolsky Frank , Eberhardt James J.
Published: April 2007

Limitations on the use of petroleum-based diesel fuel in California could occur pursuant to declaration by the California Air Resources Board (CARB) that the particulate matter component of diesel exhaust is a toxic air contaminant subject to the state’s Proposition 65. It is the declared intention of CARB not to ban diesel fuel, per se, at this time. Assuming no total ban, Argonne National Laboratory (ANL) explored two feasible “midcourse” strategies that result in some degree of (conventional) diesel displacement. In the first case, substantial displacement of compression-ignition (CI) by spark-ignition engines occurs and diesel fuel remains admissible for ignition assistance as a pilot fuel in natural gas–powered heavy-duty vehicles. Daily gasoline demand in California increases by 32.2 million L (8.5 million gal) overall, about 21 percent above the 2010 baseline demand projected by California’s energy and environmental agencies. Daily natural gas demand increases by 13.6 million diesel L (3.6 million gal) equivalents, about 7 percent above projected (total) consumption level. In the second case, CI engines utilize substitutes having similar ignition and performance properties for petroleum-based diesel. For each case, ANL estimated localized air emission plus generalized greenhouse gas and energy changes. Fuel replacement by dimethyl ether yields the greatest overall reduction in nitrogen oxide emissions. All scenarios bring about fine particulate matter (PM10) reductions relative to the 2010 baseline, with greatest reductions from the CI-displacement case and the least from fuel replacement by Fischer-Tropsch synthetic diesel. Institutional and cost implications of vehicle and engine replacement were not formally evaluated.
Benefit-Cost Evaluation of Traveler Information: Seattle’s Washington State Department of Transportation Website
Authors: Lee Douglass B.
Published: April 2007

The Washington State Department of Transportation website allows those with access to a computer and the Internet to obtain current information about traffic conditions on freeways and bridges in the metropolitan Seattle area. Potential benefits of disseminating real-time traveler information are time and cost savings to users as a result of informed travel choices (route, time, mode, destination, add or forgo a trip), increased user confidence in travel choices, and reduction in congestion, pollution, and other external costs. These benefits depend on how many users access the information, what choices they make, how much time they save or in what other ways they find the information valuable, and how their choices affect the transportation system. Although a good deal of this information is available for Seattle or can be estimated from comparable contexts, the data are inadequate to determine within a broad range whether net benefits are positive or negative. A spreadsheet model is presented that allows relevant data to be applied—and “what if” numbers to be inserted where necessary—as a basis for identifying the performance characteristics and levels needed to make a traveler information service a worthwhile investment.
New Carquinez Bridge, Northeast of San Francisco, California: Technological Design Advancements
Authors: Spoth Thomas , Khazem Dyab , Orsolini Gregory I.
Published: April 2007

The new Carquinez Strait Bridge, northeast of San Francisco, California, will be the first major suspension bridge to be constructed in the United States since the second Chesapeake Bay Bridge in Maryland in 1973. It will replace an existing steel cantilever truss bridge, built in 1927, that was found to be seismically inadequate. The new bridge consists of an orthotropic closed steel box girder superstructure, two main cables 512 mm (20 1/8 in.) in diameter, reinforced concrete towers, and gravity anchorages. The design has set a new standard in modern suspension bridge design in the United States, particularly with respect to seismic safety. Some of the key elements of the design that are discussed are the global design loading criteria for long-span suspension bridges, the design of allowable stresses in main cable wire, the state-of-the-art design detailing of critical welded connections, the finite-element analysis approach for the box girder to determine the actual plate stresses and stress concentrations, and the design of the reinforced concrete tower leg sections for enhanced ductile seismic performance.
Field Performance of Stress-Laminated Timber Bridges
Authors: Ritter Michael A. , Rimal Duwadi Sheila , Wacker James P.
Published: April 2007

Stress-laminated timber bridges were introduced into the United States in the late 1980s. Since then this concept has been used for more than 500 bridges constructed on roadways throughout the United States. To evaluate the performance of these bridges, the Forest Products Laboratory of the U.S. Department of Agriculture Forest Service and FHWA initiated a nationwide bridge-monitoring program. A field evaluation and the results obtained through that monitoring program for stress-laminated bridges that have been continuously monitored for 2 or more years after installation are presented. Included are discussions related to bridge design and construction, moisture content, stressing bar force, vertical creep, load test behavior, and condition evaluation. On the basis of the monitoring program results, the performance of stress-laminated timber bridges is generally satisfactory, although there are areas in which performance can be improved.
Upgrading Missouri Transportation Infrastructure: Solid Reinforced-Concrete Decks Strengthened with Fiber-Reinforced Polymer Systems
Authors: Alkhrdaji Tarek , Nanni Antonio , Mayo Randy
Published: April 2007

More than 40 percent of the bridges in the United States need repair, strengthening, or replacement. Because of limited funds, many states are forced to post load restrictions on their bridges as a temporary measure. Recently, fiber-reinforced polymers (FRPs) have emerged as a practical solution for repair or strengthening of highway bridges. Since there are no nationally accepted specifications for design and construction with bonded FRP reinforcement, the Missouri Department of Transportation (MoDOT) has funded a research program aimed at validating the design and analysis procedure through strengthening and testing to failure of bridges under realistic highway loading and conditions. Two bridges, Bridge G270 and Bridge J857, were selected for this demonstration. Both bridges are solid reinforced-concrete (RC) slab bridges. Bridge G270 was strengthened to increase its load-carrying capacity by using externally bonded carbon FRP and is still in service. Two of the three deck slabs of Bridge J857 were strengthened with FRP composites. Elastic tests were conducted on Bridge G270 before and after strengthening. Laboratory and field tests were conducted to validate the analytical model and design capacity. The decks of Bridge J857 were tested to failure under static loads. Test results indicate that strengthening with FRP can increase the capacity of solid-slab bridge decks. Strength and failure modes can be predicted by using the classical approach for RC design and analysis, based on equilibrium and compatibility. The research program, strengthening techniques, test results, and modes of failure of the bridge decks tested are reported.
Winter Friction Project in Norway
Authors: Dahlen Jon , Vaa Torgeir
Published: April 2007

The Winter Friction Project in Norway deals with practical, technical, and economic problems arising in providing good friction on winter roads. One of the main activities throughout the whole project period will be to carry out field studies, which will consist of (a) a testing program (scientific studies) to document performance of different friction improvement methods and (b) a follow-up study on roads in 10 counties to document existing winter maintenance practice on both salted and sanded roads. Scientific studies during the 1998–1999 winter season revealed that new measures carried out with sanding methods last longer than do traditional sanding methods. Although the effect of using cold and dry sand can disappear after the passage of 50 vehicles, it has been proved that by using heated materials or adding warm water to the sand it is possible to maintain a friction level above the standard, even after the passage of 2,000 vehicles. In particular, a method using a mix of hot water and sand showed promising results. During summer and autumn 1999, the warm-wetted sanding method was further improved by development of two new Norwegian prototypes. These new spreaders have been tested together with alternative ways of adding water (type of spreader and temperature of the water). Wet sand has been compared with traditional sanding using dry materials. The field tests carried out during the winter season 1999–2000 with wet sand and roller distributor confirm the results from last season. Good results were achieved with the Norwegian trucks.
Taking Tire Slip Ratio into Account and Estimating Friction Coefficients in Rear-End Collisions on Winter Roads
Authors: Nakatsuji Takashi , Hosseinlou Mansour , Kawamura Akira , Onodera Yuki
Published: April 2007

Road surface conditions in winter are very transient. A small change in the friction coefficient can have a large effect on vehicular movements. A friction coefficient measured at the scene directly after an accident may be different from the one at the time when the accident occurred. A traffic accident reconstruction method that can estimate friction coefficients based indirectly on in situ data is presented. First, it is pointed out that the friction coefficient is largely dependent on the tire slip ratio, in particular that of studless tires whose tread rubber is very soft and adhesive. It is emphasized that it makes sense to use a tire model that considers the slip ratio to estimate the friction coefficients more precisely. Rear-end collision accident data were collected. The types of vehicles involved in accidents were identified, and their friction coefficients at the time of skidding were estimated by the new reconstruction model. The friction coefficients estimated by this model were compared with those estimated by a conventional rigid-body model. In addition, by inversely calculating the friction coefficient required to avoid accidents, how an increment in the friction coefficient could greatly improve traffic safety is considered. Finally, it is shown that a threshold defined as the intersection of the cumulative curves of both friction coefficients provides useful information for winter maintenance.
Liquid Anti-Icing Chemicals on Asphalt: Friction Trends
Authors: Leggett Timothy S. , Sdoutz Gerald D.
Published: April 2007

Research was done to determine whether there existed a chemical “slipperiness”on an asphalt surface as a result of a transition of typical anti-icing chemicals currently in use from a liquid to a solid state, and vice versa. The research has shown that during the state transition of most anti-icing chemicals a “slurry”phase is formed. This produces a relatively short-lived reduction in the coefficient of friction for most chemicals. At relative humidity levels in the high 20s to low 30s, most chemicals begin to dry out after application as a liquid, causing the state transition. Humidity values above those required to cause the state transition appear not to affect the friction dramatically. All chemicals, upon continued dehydration, reached a solid state. The solid state coefficient of friction of most chemicals is essentially equivalent to that of a clean and dry asphalt roadway. Some even increased the coefficient of friction above 1.0. It appears that prudent use of the chemicals, particularly with regard to application rate, frequency, and other contaminants, while bearing in mind expected humidity levels, can further reduce the likelihood of slickness developing, particularly in the fall season when most incidents are reported. It is believed that most anti-icing agent-related incidents are probably a result of the chemical being applied after a dry period, which likely causes a slippery emulsion to be formed by the chemical and the contaminants that have built up on the roadway.
Methods for Measuring and Reporting Winter Maintenance Activities
Authors: Vaa Torgeir
Published: April 2007

The Winter Friction Project in Norway deals with practical, technical, and economic problems that arise in providing good friction conditions on winter roads. The project started in 1997, and the final report is scheduled for 2002. A main activity throughout the project period is to carry out field studies. The field studies consist of a testing program (scientific studies), to document performance of different friction improvement methods, and a follow-up study on roads in 10 counties, to document existing winter maintenance practice on both salted and sanded roads. The project has a need for measuring and reporting winter maintenance activities and winter standards in connection with scientific studies and as a part of the follow-up study. A system has been developed to evaluate the effects of different actions. The difference in standard achieved between salted and sanded roads is clear and is reflected in the number of measures and the friction standard. The results so far show that there is a difference in practice, which can be explained in part by different climatic and traffic conditions. But the results also show that there are differences in practice where the outer conditions are similar. This indicates that there is a potential for improvement, and changes will be made in view of the results from the scientific study.
Procedures for Winter Storm Maintenance Operations in Northern Arizona
Authors: Boselly S. , Blackburn Robert R. , Amsler Duane E.
Published: April 2007

The Arizona Department of Transportation (ADOT) is responsible for snow and ice control on state-designated highways in Northern Arizona. The processes and procedures for winter maintenance have evolved from the early days of snow removal only. These procedures sometimes prevent adequate mobility of the motoring public during winter storms or result in road closures because of snow or ice problems on the roads. In 1997, ADOT contracted with a team of snow- and ice-control experts to review existing practices and procedures and to make recommendations to improve snow and ice control. The review process included investigating ADOT’s use of weather information, the location of Road Weather Information System (RWIS) sites and plans for new sites, existing resources and procedures for snow and ice control, maintenance of RWIS and snow- and ice-control equipment, and training of personnel. The original statement of the research problem and its objective are presented, the research findings are summarized, and recommendations delivered to ADOT, designed to improve snow and ice control in Northern Arizona, are documented. Attention was given throughout the analysis and subsequent recommendations to the special need for snow and ice control in the transition zone, the region between the desert valley and the high country of Arizona.
Client-Oriented Winter Road Maintenance: A Case from the Savo-Karjala Region of Finland
Authors: Karjalainen Jukka
Published: April 2007

The development of client-oriented winter road maintenance began in spring 1998. Road users were not satisfied with the level of winter maintenance based on national winter maintenance standards. The standards could not address specific needs of individual roads. The objective of client-oriented winter road maintenance is to improve service provided for road users through better timing and focused maintenance activities that are based on the needs of clients. The special terms of client-oriented maintenance were first included in bid solicitations for winter 1998–1999. Selection of road sections and definition of requirements were based on information from the customer-feedback system, from a survey of companies, and from the experience of road masters and site engineers. On the low-traffic road network, client-oriented maintenance requirements were used on roads where normal condition demands and cycle times were not adequate for commercial traffic. On main roads, requirements included “jubilee quality” maintenance for busy holiday traffic, and some road sections had extra demands for nonskid treatment beyond the standard. The client-oriented maintenance experience has been positive. Client satisfaction and traffic safety appear to have improved. The extra cost is small because most of the requirements can be fulfilled through better timing of maintenance activities. Opinions concerning the effects of client-oriented winter road maintenance largely are based on the experience and observations from the trial winter. More research work is needed so that effects can be better estimated.
Evaluation of Virginia’s First Heated Bridge
Authors: Hoppe Edward J.
Published: April 2007

The goal of the Heated Bridge Technology Program, established in 1991 under the Intermodal Surface Transportation Efficiency Act, is to find durable and environmentally friendly heated bridge technologies for ice and snow removal. The first heated bridge built in Virginia is evaluated. The bridge is on Route 60 over the Buffalo River in Amherst County. The project was monitored from its construction in 1995 through winter operations terminating in spring 2000. Data were collected remotely using an electronic data logger interfaced with various temperature and environmental sensors. An infrared camera was used to examine heat distribution across the bridge deck. The results of the study demonstrate that heat pipe technology can provide a feasible option for heating decks. However, substantial problems were encountered in getting the system to perform as designed. It appears that the control aspect of this technology requires additional improvements to ensure reliable operation under field conditions.
Modeling Approach to Design of a Ground-Source Heat Pump Bridge Deck Heating System
Authors: Chiasson Andrew , Spitler Jeffrey D.
Published: April 2007

The approach taken to design a hydronic snow-melting system for a bridge deck on an Interstate highway in Oklahoma is described. A vertical borehole, closed-loop ground-source heat pump system is to be used as an energy-efficient means to provide the heating requirement. It is proposed to use the bridge deck as a solar collector in the summer months so that the ground can be thermally “recharged” by circulating fluid from the bridge deck to the ground. A design of this type involves the determination of a number of interdependent variables that are difficult or impossible to accurately quantify by conventional design practices. Therefore, mathematical models of a hydronically heated pavement slab, water-to-water heat pump, and a ground loop heat exchanger were developed for use in a detailed system simulation. The simulation allowed design parameters such as minimum heat pump entering fluid temperature, number of heat pumps, and flow rate to be varied, and several potential designs that kept the bridge surface temperature above freezing were selected. The hourly heating loads for candidate configurations were then used to estimate the required size of the ground loop heat exchanger. There is a trade-off between the number of boreholes that make up the ground loop heat exchanger and the number of heat pumps required. Of the configurations examined, a system with 16 heat pumps of nominal 106-kW capacity and 250 boreholes, each 76 m deep, was selected.
Impact of New Railway Technology on Grain Transportation in Western Canada
Authors: Dick C. , Clayton Alan M.
Published: April 2007

The impacts on railway technical productivity, infrastructure, and costs created by the introduction of new railway technology to the movement of grain in Western Canada are evaluated. By creating a geographic information system model of the railway system and assigning grain traffic to individual railway lines, operational and maintenance parameters are determined for each railway segment under a variety of scenarios. The scenarios consider the implementation of new high-horsepower locomotives and heavier freight cars. Because four new trains can do the work of five current trains, new technology decreases the number of trains and amount of equipment required, decreasing the cost of transport. Although the new cars negatively affect the infrastructure through higher axle loads, decreases in the number of trains operated more than offset associated roadway maintenance increases. The benefits of the new technology are more apparent on Canadian Pacific than on Canadian National because of the steep grades and long trains associated with Canadian Pacific operations. Over the service life of the new technology, approximately $260 million [in Canadian dollars (C$1 = US$0.65)] will be saved. Additional benefits can be obtained by performing additional upgrades to the railway infrastructure.
Estimation of Investment in Track and Structures Needed to Handle 129 844-kg (286,000-lb) Railcars on Short-Line Railroads
Authors: Resor Randolph R. , Zarembski Allan M. , Patel Pradeep K.
Published: April 2007

Ownership of the U.S. rail industry is divided between eight Class I railroads (those with more than $258.5 million in annual revenue) and about 550 regional and short-line railroads. The eight large railroads own about 70 percent of the 273 700 track-km (170,000 track-mi) and account for about 90 percent of industry revenues. The remaining 30 percent of track kilometers belongs to the regional and short-line railroads, which must operate and maintain them with 10 percent of industry revenues. U.S. railroads function as an integrated network; freight originating on a short-line railroad can be delivered anywhere in the United States, Canada, or Mexico. Equipment is freely interchanged, so the small railroads must handle the same heavy cars as the Class I railroads even though maximum freight car weights have increased in recent years, with cars of 129 844 kg (286,000 lb) becoming common. Many of the smaller railroads own trackage that had been branchlines belonging to the larger companies, and track components and condition are often marginal or inadequate to handle the heavier loads. Yet, if short lines cannot handle heavier cars, they face a loss of revenue and ultimately business failure. ZETA-TECH conducted a survey of short-line and regional railroads to determine the quantities of track materials, bridge repairs, and replacements needed to handle heavier cars. Using standard railroad industry unit costs, ZETA-TECH estimated the cost of this work at $6.86 billion in 1999 dollars.
Results of California Department of Transportation Litter Management Pilot Study
Authors: Lippner Gary , Johnston John , Combs Suzanne , Walter Kimberly , Marx David
Published: April 2007

Litter is receiving increasing attention as a water pollutant, especially near Southern California beaches. To investigate the characteristics of litter in freeway storm water and the effectiveness of various best management practices (BMPs), the California Department of Transportation (Caltrans) conducted a 2-year litter management pilot study in the Los Angeles area. New litter sampling and monitoring protocols were devised to characterize litter and to test BMP effectiveness. Twenty-four freeway catchments were monitored. Half the catchments were treated with one of five BMPs; the others were controls. The BMPs tested were increased street sweeping frequency, increased frequency of manual litter pickup, a modified drain inlet, a bicycle grate inlet, and a litter inlet deflector (LID) developed during the study. Litter discharges were quantified by weight, volume, and count and were further classified by composition. Roughly half the freeway storm water litter was found to consist of paper, plastic, and Styrofoam. With the exception of cigarette butts, the origins of most litter items could not be identified because of their small size. Of the five BMPs tested, only increased litter pickup and the modified drain inlet demonstrated some apparent reduction of litter in storm water runoff, although the data are highly variable. Increased frequency of sweeping, the bicycle grate, and the LID did not reduce litter effectively in storm water discharges monitored during the study.
Step-Pool Morphology in High-Gradient Countersunk Culverts
Authors: Maxwell A. R. , Papanicolaou A. N. , Hotchkiss R. H. , Barber M. E. , Schafer J.
Published: April 2007

Bed stability and morphology in countersunk culverts on steep slopes were examined to improve understanding of the parameters governing sediment flow characteristics in mountain streams. The knowledge gained was used to provide preliminary construction guidelines for the stream simulation approach of countersunk culverts, an approach that is under consideration in Washington State. Prototype conditions were evaluated in a flume for a 30 percent countersunk culvert with slopes ranging from 3 percent to 7 percent and particle relative submergence varying from 0.5 to 2.0 for three bed size distributions. The experiments were designed to satisfy the conditions of dynamic similarity, and they are preferred to field measurements because they allow a high degree of control over testing conditions. It was found that step-pool bedforms are the most ubiquitous features along the culvert gravel bed. A new formula was developed that correlates step height with the gravel-bed size distribution, relative submergence of the particles, and the Froude number. The step spacing was found to be related to step height and streambed longitudinal slope. This information was combined into a generic design method for streambed simulation of high-gradient countersunk culverts. An example case that illustrates the application of the newly derived formulas to the construction of a gravel bed for a countersunk culvert is provided.
Compliance Testing of a Bullnose Median Barrier System; NCHRP Report 350
Authors: Bielenberg Bob W. , Reid John D. , Faller Ronald K.
Published: April 2007

A new bullnose guardrail system for the treatment of median hazards was developed and successfully crash tested according to the safety criteria set forth in NCHRP Report 350. The new system consists of a nose section 4500 mm wide by 4824 mm long, comprising three sections of curved thrie beam guardrail attached to parallel sides of thrie beam guardrail 4500 mm apart. The nose section was designed to safely capture and contain vehicles impacting the nose. Two 6 × 25 steel cables were attached behind the top two humps of the nose section to ensure vehicle capture in the event the thrie beam ruptured. Additionally, the first five sections of guardrail had horizontal slots cut in the valleys of the rail to improve vehicle capture and reduce the formation of large kinks that could pose a threat to a vehicle as the system deformed to absorb an impact. The research study included computer simulation modeling using LS-DYNA and full-scale vehicle testing using 2000-kg pickup trucks and 820-kg small cars in accordance with the Test Level 3 safety performance requirementd specified in NCHRP Report 350. Nine full-scale crash tests were performed on the new system. Several changes were made to the bullnose system to improve its safety performance during the course of the testing and development.
Washington State Cable Median Barrier
Authors: Albin Richard B. , Lance Bullard D. , Menges Wanda L.
Published: April 2007

In the mid-1960s, the New York State Department of Transportation developed a three-strand cable barrier that has several desirable characteristics as compared with other roadside barriers. This system was crash tested in accordance with the NCHRP Report 350 crash test criteria as a roadside barrier. In the roadside barrier, all three cables are placed on the traffic side of the posts. Since 1988, the AASHTO Roadside Design Guide has contained information on a cable median barrier design in which the middle cable is mounted on the opposite side of the posts so that it can contain and redirect vehicles that strike the system from either side. In the early 1990s, the Washington State Department of Transportation (WSDOT) became interested in using this design for medians that are more than 10 m wide. WSDOT sponsored crash tests to evaluate the performance of this barrier, in accordance with NCHRP Report 350 criteria, with a small car and a pickup truck. In both tests, the vehicle was contained and brought to a stop. The occupant risk values were within the preferred limits set by NCHRP Report 350, and the damage to both vehicles was relatively minor.
W-Beam Guardrail Adjacent to a Slope
Authors: Polivka Karla A. , Fallen Ronald K. , Sicking Dean L. , Rohde John R.
Published: April 2007

A W-beam guardrail system was developed and successfully crash tested for use on a 2:1 foreslope. The guardrail design was constructed with W-beam rails 2.66 mm thick (12 gauge) totaling 53.34 m in length, and it incorporated a half-post spacing section of 17.15 m. The W-beam rail was supported by 15 W150 × 13.5 steel posts 1829 mm long, spaced 1905 mm on center, and 19 W150 × 13.5 steel posts 2134 mm long, spaced 952.5 mm on center. Routed, 150 × 200 × 360 mm wood spacer blockouts were used to block the rail away from each post. The research study included bogie testing on steel posts placed in sloped fill, computer simulation modeling with BARRIER VII, and one full-scale vehicle crash test, using a 2000-kg pickup truck. The test, impacting at a speed of 100.7 km/h and an angle of 28.5 degrees, was conducted and reported in accordance with the Test Level 3 (TL-3) requirements specified in NCHRP Report 350. The safety performance of the W-beam barrier system was determined to be acceptable according to TL-3 criteria.
Improvements to the Weak-Post W-Beam Guardrail
Authors: Ray Malcolm H. , Engstrand Klas , Plaxico Chuck A. , McGinnis Richard G.
Published: April 2007

The weak-post W-beam guardrail has been widely used in the Northeast for many decades. Weak-post guardrails are characterized by larger dynamic deflections in a collision and are considered more forgiving than other, stiffer barriers. Most states have experienced good performance with these barriers over the last several decades if adequate clear space is provided behind the barrier. Unfortunately, recent crash tests of the standard weak-post W-beam guardrail involving a 2000-kg pickup truck resulted in a series of unacceptable test results, including overriding and penetrating the guardrail. Design modifications to the weak-post W-beam guardrail were explored by using finite element simulations and full-scale crash tests. An improved version of the weak-post W-beam guardrail system was developed and tested, and this was found to satisfy the requirements of NCHRP Report 350 for Test Level 3.