bluuebunny/crossref_metadata_2025 huggingface dataset:
Saskatchewan Highways and Transportation Reduced Tire Pressure Initiative
Authors: Davies Thomas L. , Wall Tami F. , Carpentier Allan
Published: April 2007

After examination of the research carried out by other agencies, Saskatchewan Highways and Transportation (SHT) embarked on an initiative to adapt low tire pressure technologies to the province's needs and environment. The focus of the initiative was to explore several technical questions from SHT's perspective: (a) Can low tire pressures be used to increase truck weights from secondary to primary without increasing road maintenance costs on thin membrane surface roads? (b) What are the short- and long-term effects of tire heating under high-speed/high-deflection constant reduced pressure (CRP) operations in a Saskatchewan environment? (c) What effects do lower tire pressures have on vehicle stability at highway speeds? To date, significant opportunities have been noted on local hauls (less than 30 min loaded at highway speeds) for CRP operation and long primary highway hauls that begin or end in relatively short secondary highway sections that limit vehicle weight allowed for the whole trip for central tire inflation technology. The background and environment for the initiative and the investigations and demonstrations envisioned and undertaken are briefly outlined.
Effect of Lowered Tire Pressures on Road Erosion
Authors: Foltz Randy B. , Elliot William J.
Published: April 2007

The effect of tire pressure on sediment produced by loaded logging trucks operating on low-quality aggregate surfaced roads is analyzed. Rainfall and runoff were measured for three winter seasons with logging truck traffic. Sediment eroded from the road surface from moderately reduced tire pressure road sections averaged 45 percent less than from the highway tire pressure sections. An average reduction of 80 percent was measured from the section used by trucks operating with low tire pressure sections. Because the processes responsible for sediment reduction are not site specific, lowering tire pressures in logging trucks on unpaved roads can reduce the sediment loss from many unpaved road surfaces. The results were used to calibrate the Water Erosion Prediction Project (WEPP) model. Once calibrated, the model estimated the sediment reduction expected at representative locations for all national forests. The WEPP model demonstrated its ability to be helpful in estimating the sediment reduction from forest roads.
Potential Factors Affecting Flow Consistency Test Method for Controlled Low-Strength Materials
Authors: D'Andria Gilberto G. , Frost J. David , Ashmawy Alaa , Patterson Kyle R.
Published: April 2007

Controlled low-strength material (CLSM) is a mixture of portland cement, fly ash, sand, and water. A provisional standard for evaluating the flow consistency of this material has been recently developed by ASTM (PS 28-95). The procedure consists of filling a standardized cylinder with CLSM and lifting the cylinder by a steady upward motion, thereby allowing the CLSM to flow out and form a conical pile. The spread diameter is the average of two manually taken measurements of the base of the pile in orthogonal directions. The authors are developing a flow index test (FIT) for granular materials based on the CLSM flow test. During development of this index test, a number of parametric studies have been done to investigate the influence of material- and procedure-related factors on the test results. These studies indicate that the results obtained with the FIT procedure depend on a number of factors. Because inertia forces and surface friction coefficients are important factors for both wet and dry granular flow, the same factors are expected to affect the results of the CLSM flow consistency test.
Dust Control: Australasian Experiences with Various Chemical Additives
Authors: Giummarra George J. , Foley Graham , Cropley Stephen
Published: April 2007

Road dust can degrade agricultural produce, affect health, reduce road safety, increase wear and tear on vehicles, and increase the rate of deterioration of the roadway. In October 1996, Australian Road Research Board Transport Research completed and published a study of various dust-control techniques. That report encompassed a worldwide literature search on various measures to control dust and a survey of municipal councils and other road authorities across Australia and New Zealand to ascertain what experiences people have had with the use of dust suppressants. The outcome of this study is to provide a guide to the reported effectiveness of particular dust suppressants under given circumstances and other methods to better control dust emissions.
Evaluating Groundwater Pollution Susceptibility of Dust Suppressants and Roadbed Stabilizers: Case Study of a Petroleum-Based Product
Authors: Kimball Colin E
Published: April 2007

Current environmental regulations have prompted regulatory officials, users, and manufacturers of roadbed stabilizers and dust suppressants to evaluate the environmental impact of these products to ensure that human health and the environment are not compromised through their use. Because roadbed stabilizers and dust suppressants are inherently designed to prevent dust emissions and erosion, this study focuses on evaluating the groundwater pollution susceptibility of roadbed stabilizers and dust suppressants. Current techniques used in evaluating hazardous waste sites to estimate the fate and transport of constituents in the subsurface are useful for evaluating roadbed stabilizers and dust suppressants. Chemical properties of roadbed stabilizers and dust suppressants along with generic soil property parameters can be incorporated into screening-level mathematical models to estimate constituent target-level concentrations in groundwater. These techniques were applied to a petroleum-based soil stabilizer and dust suppressant known as Pennz-Suppress D (petroleum-based product). The content of Environmental Protection Agency priority pollutants was determined by laboratory analysis. Further testing with leachate extraction methods provided additional data on leachability of the petroleum-based products under assumed worst-case conditions. Mathematical modeling was used to qualify the results. Groundwater pollution susceptibility results indicate a low risk for the product to adversely affect groundwater.
Effect of Aggregate Degradation on Specimens Compacted by Superpave Gyratory Compactor
Authors: Collins Ronald , Watson Donald , Johnson Andrew , Wu Yiping (Peter)
Published: April 2007

Aggregate degradation during gyratory compaction may cause changes in the original gradation of the aggregate, and it may also affect volumetric requirements for Superpave Level I mix design. The effect of aggregate degradation on the design gradation and final volumetric properties of the asphalt mix compacted by the Superpave gyratory and Astec vibratory compactors was evaluated. Because vibratory compaction is an alternative compaction method that simulates field compaction, a vibratory compactor developed by Astec Industries, Inc., was used for comparison with the Superpave gyratory compactor. Aggregates with high and low Los Angeles abrasion losses were used to evaluate the effect of aggregate toughness or abrasion resistance on gradation change and volumetric properties. The changes in the amount of material passing the 0.075-mm sieve due to aggregate degradation during compaction were not significant enough to prevent specimens from meeting dust proportion requirements, regardless of whether low-or high-abrasion loss aggregates were used. A mix containing high-abrasion aggregate was less likely to meet restricted zone requirements than a mix using low-abrasion aggregate after degradation resulting from compaction.
Fracture Morphology and Fracture Toughness Measurement of Polymer-Modified Asphalt Concrete
Authors: Bhurke Alekh S. , Shin E. Eugene , Drzal Lawrence T.
Published: April 2007

Pavement distress occurs through a variety of mechanisms, but it is always controlled by the adhesive and cohesive performance of the asphalt binder. Although the causes of pavement failures are known, the precise mechanisms by which they occur remain to be understood. Observation of the fracture morphology of asphalt concrete can provide some information in this respect. The fracture morphology of asphalt concrete is dependent on the morphology of the binder. A network structure was observed in thin asphalt binder films and the fracture morphology and engineering properties of asphalt concrete were found to be dependent on the network morphology of the asphalt binder. Addition of polymers to asphalt binders causes changes in the nature of the network structure, and its effect can be qualitatively determined by characterizing the fracture morphology. Styrene butadiene styrene (SBS), styrene ethylene butylene styrene (SEBS), styrene butadiene rubber (SBR) latex and an epoxy-terminated reacting polyolefin (Elvaloy AM) were used in this study. A quantitative method to determine the effect of polymer modification on the fracture properties of asphalt concrete is the J-contour integral fracture toughness measurement. An experimental protocol to measure the critical J-integral fracture toughness ( J1 c) was developed and the low temperature (-10°C) J1 c values were determined for SEBS and Elvaloy AM-modified asphalt concrete at three different concentrations.
Interpretation of Indirect Tension Test Based on Viscoelasticity
Authors: Drescher A. , Newcomb D. E. , Zhang W.
Published: April 2007

The diametral indirect tension test is a convenient configuration for determining the modulus of asphalt concrete samples. The resilient modulus test has been a traditional approach to characterizing the stiffness of asphalt concrete, but it leaves much to be desired when considering the viscous behavior this material exhibits, even at low temperatures. A method for determining the complex compliance, complex modulus, and phase angle of asphalt mixtures using the indirect tensile test and a haversine load history is presented here. This test may be performed over a range of frequencies and temperatures as demonstrated on materials used in the Minnesota Road Research Project. The use of the haversine loading simplifies the test when compared with the pulse loading and rest time used in the resilient modulus test, and it allows for the characterization of the elastic and viscous components of the material's overall behavior, which is very difficult, at best, with the current test methods.
Evaluation of Rut-Resistant Properties of Asphalt Mixes Under Field and Laboratory Conditions
Authors: Oliver John W. H. , Jameson Geoffrey W. , Sharp Kieran G. , Vertessy Nicholas J. , Johnson-Clarke James R. , Alderson Allan J.
Published: April 2007

The AUSTROADS Pavement Research Group and the Australian Asphalt Pavement Association agreed to support an accelerated loading field trial using the accelerated loading facility (ALF) to determine if newly developed test equipment and procedures could produce asphalt mixes with improved resistance to rutting. An extensive laboratory evaluation program was also undertaken for comparison of the predicted results with those observed under ALF loading. The results of the field trial and the laboratory tests, and their relationship, are presented.
Design, Construction, and Analysis of Pavements Using Accelerated Loading Facility
Authors: Roberts Freddy L. , Mohammad Louay N. , Djakfar Ludfi , Raghavendra Amar
Published: April 2007

The Louisiana Transportation Research Center has recently completed the construction of a full-scale pavement test facility using the accelerated loading facility (ALF) machine. This facility contains nine pavement test sections, 12-m (38-ft) long and 3.66-m (12-ft) wide that are loaded by the ALF machine with loads ranging from 34.71 to 111.25 kN (7,800 to 25,000 lbf) on a dual-tire assembly. The advantage of this testing facility is its ability to cause a pavement to fail in a short period of time. In addition, the data acquisition methods and instrumentation used in this testing facility allow researchers to obtain reliable and representative performance data. The first test section has been loaded to failure and a preliminary analysis of the data is completed. VESYS 3A-M, a microcomputer version of the VESYS series, has been selected for the analysis due to its ability to predict damage and its flexibility. The analysis consists of the primary response analysis to determine strains, stresses, and deflection of the pavement and damage-prediction modeling that includes rutting, fatigue cracking, and roughness. The analysis was conducted by comparing the data obtained from field with that predicted by VESYS 3A-M. The performance data obtained from the field include fatigue cracking, rutting, and roughness. The analysis showed that VESYS 3A-M outputs are in good agreement with those obtained from the field.
Analysis of Pavement Rutting Data from FHWA Pavement Testing Facility Superpave Validation Study
Authors: Bonaquist Ramon F. , Mogawer Walaa S.
Published: April 2007

Since 1986, FHWA has been performing accelerated pavement tests at its Pavement Testing Facility (PTF) located on the grounds of the Turner-Fairbank Highway Research Center. At this laboratory, FHWA uses two accelerated loading facility pavement testing machines to simulate the effects of heavy vehicle loading on full-scale test pavements. In 1992, FHWA, with help from Strategic Highway Research Program staff and contractors, started an experiment to validate selected aspects of the Superpave binder specification using accelerated pavement tests. Twelve test lanes with 48 individual test sites were constructed at the PTF in 1993. The results of accelerated pavement tests on these pavements will be used to validate the Superpave binder parameters for rutting and fatigue cracking.
Selecting Most Desirable Hot-Mix Asphalt Mixtures
Authors: Sebaaly Peter E. , Ridolfi Dan , Gangavaram Raja S. , Epps Jon A.
Published: April 2007

Aggregate properties and gradations have been shown to have a significant impact on the strength and performance of HMA mixtures. Strength properties, such as the resilient modulus and tensile strength, and performance properties, such as moisture sensitivity, permanent deformation, and low-temperature cracking, play a major role in the field performance of HMA mixtures. However, it is believed that by changing the aggregate gradation and the asphalt binder, a desirable hot-mix asphalt mixture can be achieved for any source of aggregate. The data and analysis of a laboratory research study that evaluated four gradations and four asphalt binders in conjunction with five sources of Nevada aggregates are summarized. The measured material properties include the Superpave binder and aggregate properties, the strength properties, and the permanent deformation and low-temperature cracking of the mixtures. The data analysis indicated that the resilient modulus and tensile strength tests can be used in lieu of the more complicated triaxial repeated-load test to ensure against rutting and that the binder property can be used to ensure against low-temperature cracking.
Relation Among Average Speed, Flow, and Density and Analogous Relation Between Density and Occupancy
Authors: Cassidy Michael J. , Coifman Benjamin
Published: April 2007

To counter the growing body of literature disputing that average vehicle speed is the ratio of flow to density, the relation is shown to hold as an identity when the variables are defined in the manner described by Edie. In similar fashion, the analogous relation between density and occupancy is shown to be true. These identities are illustrated with data measured by paired loop detectors, which underscores that Edie’s definitions are natural ways to treat the variables. The detector data are further used to show that any disputes surrounding the validity of these identities are largely the result of having defined (i.e., measured) the traffic variables in some other ways.
Modeling and Estimation of Headway Distributions
Authors: Hoogendoorn Serge P. , Botma Hein
Published: April 2007

A simple analysis to derive Branston’s generalized queueing model for (time-) headway distributions is presented. It is assumed that the total headway is the sum of two independent random variables: the empty zone and the free-flowing headway. The parameters of the model can be used to examine various characteristics of both the road (e.g., capacity) and driver-vehicle combinations (e.g., following behavior). Furthermore, the model can be applied to vehicle generation in microscopic simulation models and to safety analysis. To estimate the different parameters in the model, a new estimation method is proposed. This method, which was developed on the basis of Fourier-series analysis, was successfully applied to measurements collected on two-lane rural roads. The method was found to be both computationally less demanding and more robust than traditional parameter techniques procedures, such as maximum likelihood. In addition, the method provides more accurate results. Parameters in the model were examined with the developed estimation method. Estimates of these parameters at a specific period and a specific measurement location were to some extent transferable to other periods and locations. Application of the method to road capacity estimation is discussed.
Establishing National Distributed Network For Long-Term Pavement Performance Information Management System
Authors: Rowshan Shared , Harris Sandra B. , Rabinow Scott D.
Published: April 2007

FHWA’s Long-Term Pavement Performance (LTPP) information management system (IMS) is a relational database management system that has been developed to collect the data necessary to accomplish the goals of the LTPP program established under the Strategic Highway Research Program. The LTPP database and the technology available to collect and manage the data have evolved a great deal since the initial design of the system in 1988. Data from this system are available to users by request by filling out a form. Although some upgrades have been made to hardware and software, a comprehensive evaluation of the computing environment and general IMS procedures had not been performed until the migration analysis. The original design of the LTPP IMS is based on four stand-alone IBM-compatible single-user personal computers transferring data to a minicomputer at the national center that houses all the data collected throughout the United States and Canada. The design concept and some details for the establishment of a national distributed network for the internal operation of the LTPP IMS, intended to migrate to a system that is more compatible with the current hardware and software technology, are described. On the basis of the evaluation of the options considered, cost, technical criteria, and management considerations, the design platform for migration is established as upgrades to Oracle V7, Windows NT, and a national distributed client-server environment. An Integrated Services Digital Network solution is recommended for the network communication. The proposed environment will greatly enhance the data processing and administrative capabilities of the FHWA LTPP IMS. As a result, the data availability and customer service to end users of the data such as state highway agencies would improve.
Advancements in Pavement Management Activities of Illinois Department of Transportation
Authors: Knox Ron , Babb Bill , Felts Dave , Trello George , Freeman Leigh Ann , Zimmerman Kathryn A.
Published: April 2007

For more than 20 years the Illinois Department of Transportation (IDOT) has been using the results of its Condition Rating Survey (CRS) to make policy decisions regarding pavement rehabilitation activities, assess overall network condition throughout the state, and present funding requests to the state legislature. Before the early 1990s the CRSs were conducted manually by assigning a subjective rating ranging from 1.0 to 9.0 to each pavement section in the network. Since 1994 IDOT has used automated equipment to record roughness, rutting, and faulting information and videotapes at a workstation to identify additional distress. The acquisition of the automated equipment resulted in changes to the CRS procedures. Instead of subjectively assigning a rating to a pavement section, automated sensor data are used in conjunction with the identification of up to five predominant distress types and severity levels to calculate a CRS value. Models were developed to accommodate this change within the department so that CRS ratings determined by the new procedures would be within one-half point of the rating that would have been assigned by manual procedures. In addition, the models were developed to minimize the amount of time spent biennially conducting the CRS for Interstate pavements and primary highways. As a result of the changes in the CRS procedures, the rating of the predominant distress types and severities for each pavement section became more important. For this reason, the department identified the need for additional training that could be used to supplement the annual training class and provide immediate support to the CRS raters as they performed the condition surveys. An interactive, compact-disc (CD)-based training program that features full multimedia capabilities such as video, audio, and photograph was developed. An interactive testing and assessment package is also being developed as part of the training package. A summary of the development of the CRS rating models and the CD-based training program designed to be used at the workstation as surveys are conducted is presented.
North Carolina’s Experience in Development of Pavement Performance Prediction and Modeling
Authors: Chan Paul K. , Oppermann Mary C. , Wu Shie-Shin
Published: April 2007

Development efforts in pavement performance prediction by the North Carolina Department of Transportation are described. Research into other states’ approaches was also conducted. The initial idea was to use family curves. However, because of a lack of data in key areas, it was decided to use an individual section’s pavement condition rating (PCR) data for performance prediction. The process of selection and justification of a functional form for curve fitting is detailed. An adaptive scheme to accommodate a realistic PCR history containing cycles of decline and improvement in the ratings is detailed. Abnormal sections that did not fit the models developed for individual sections were identified. These were either ( a) section with too few datum points for modeling or ( b) sections in which the last few ratings leveled out, resulting in a prediction of an unreasonably long life span. The development of family curves and their application in the processing of abnormal sections are also discussed. The developed models were then evaluated by comparing the predicted rating with the actual rating.
Roughness Level Probability Prediction Using Artificial Neural Networks
Authors: Huang Yangcai , Moore Raymond K.
Published: April 2007

The accuracy of pavement condition prediction is a major concern associated with a pavement management system (PMS). The PMS used by the Kansas Department of Transportation (KDOT) includes a project-level optimization system that requires models that estimate the probability of a given level of distress occurring. These models are based on historical pavement condition data and specific project-level data concerning pavement structural characteristics, traffic, and climatic conditions. Multiple linear regression and two artificial neural network (ANN) structures are used to predict roughness distress level probability for bituminous pavements as defined by the KDOT PMS. Since the response variable is the probability of being in a given roughness distress level, within the historical database the probability values are binary (1 if the pavement exists in a given roughness distress level or 0 if the pavement is in any other roughness distress level). This produces poorly conditioned data for regression analysis. Therefore, results indicate that ANNs have a superior ability to predict the probability of roughness distress level compared with multiple regression methods.
Evaluation of Panel Characteristics and User-Based Pavement Serviceability
Authors: Chou Chia-Pei , Wu Cheng-Lung
Published: April 2007

The effects of raters’ characteristics, vehicle classes, and highway classifications on panel ratings are described. Development of the present serviceability index (PSI) models as well as determination of the terminal PSI values for different highway classes in Taiwan also are investigated. Freeways and provincial highways as well as city streets were selected for use in evaluating road serviceability. A rating panel of 20 people rated the selected sections while they were in passenger cars and on buses. Pavement roughness also was measured with the Mays ride meter, and a manual distress survey was conducted to collect the pavement distress data. It is found that raters’ ages did not have a significant effect on the ratings, but factors of raters’ seat location on the bus, driving experience, and gender affected the ratings significantly. Another interesting finding is that raters tended to give lower ratings for freeways and provincial highways than for city streets, even if they were equally rough. Therefore, the terminal PSI of the former (2.1) was higher than that of the latter (1.8). Two PSI models that describe the relationship between panel ratings, pavement distresses, and roadway roughness are established and presented. Due to the large percentage of passengers who travel on buses within the city, a PSI model based on the ratings of city streets by a panel of raters on buses is recommended for the city system, and a PSI model developed from data for ratings of freeways and provincial highways by a panel of raters in passenger cars is recommended for highway systems.
Methodology for Developing Generic Performance Curves for Flexible Pavements in Puerto Rico Using Clustering Techniques
Authors: Colucci Benjamín , Ramírez-Beltrán Nazario , Rodríguez-Dosal Francisco
Published: April 2007

One of the major challenges that state highway agencies face is the need to estimate performance curves for different functional classifications of highways and traffic loads, considering the limitations of resources and equipment required for data collection and management activities. The need to estimate the remaining useful life of pavements in different climatic regions with a variety of subgrade conditions is crucial for the efficient allocation of maintenance and rehabilitation funds. A methodology that addresses both the performance and regional climatic aspects is presented. Essential elements of this methodology include clustering techniques for identifying the homogeneous climatic regions and determining serviceability in terms of accepted relationships of roughness and the use of nonlinear optimization to estimate performance curves based on equivalent 18-kip single axle loads and pavement serviceability index parameters. Generic performance curves have been developed for each climatic region. Application of the methodology for the cluster corresponding to the humid region is presented. The proposed methodology is expected to provide support to the Puerto Rico Highway and Transportation Authority, Strategic Highway Research Program, and the Long-Term Pavement Performance program in their pavement evaluation processes, thus contributing to the ongoing pavement management system in Puerto Rico.
Evaluation of Long-Term Pavement Performance Data Using HDM-III Probabilistic Failure-Time Models for Crack Initiation in Bituminous Pavements
Authors: Van Dam Thomas J. , Chesher Andrew D. , Peshkin David G.
Published: April 2007

Cracking is perhaps the most important distress in bituminous pavements. It plays a key role in modeling bituminous pavement performance in the World Bank’s Highway Design and Maintenance Standards Model Version III (HDM-III) with the belief that a cracked pavement is susceptible to moisture ingress, which accelerates pavement deterioration. Strategic Highway Research Program Long-Term Pavement Performance (LTPP) data were analyzed by using the probabilistic failure-time crack initiation models previously developed for use in HDM-III. On the basis of that analysis, it is concluded that the HDM-III models do not accurately capture the climatic factors that play a role in linear cracking initiation typically observed in North America. When considering only fatigue-related cracking, HDM-III models could be successfully fit to the data, but concerns related to the shape parameter call into question their general applicability. It is concluded that although some aspects of this analysis suggest that HDM-III models adequately model fatigue-related crack initiation in LTPP pavement sections, overall the results are inconclusive and a more in-depth analysis needs to be conducted.
Capabilities of Multimedia Pavement Distress Identification Training
Authors: Lake Angela I. , Van Dam Thomas J. , Zimmerman Kathryn A.
Published: April 2007

In recent years the interactive training capabilities available through multimedia technology have dramatically influenced the way in which technical material is taught. These interactive training programs feature training approaches combining graphics, audio, and video in an electronic environment that allows the user to create an individualized training process customized to each person’s level of understanding and expertise. Procedural changes in collecting pavement distress information and in the pavement condition rating process itself have created an opportunity for the Illinois Department of Transportation (IDOT) to develop a training package for its pavement distress identification program. This package demonstrates the capabilities of multimedia-based training within the pavement distress identification arena. The compact disc-based tutorial has been created for IDOT using Folio VIEWS multimedia production software and various other application software. The information contained in the program is from the Condition Rating Survey (CRS) distress manual and the Long-Term Pavement Performance program (LTPP) distress identification manual. Both distress identification procedures (CRS and LTPP) are presented in full detail, using text and graphics, to accommodate a greater number of users. The development of the training tutorial is documented, and some of the capabilities of interactive training tools are demonstrated.
Using Traffic Counts in Rural Statewide Transportation Planning
Authors: Wang Jiangyan , Wilson Eugene M.
Published: April 2007

Statewide transportation planning in a rural state is presented to illustrate demand modeling using spreadsheet programs. An interactive planning approach is developed through the planner-computer interface approach to select the most applicable traffic count data for model input. For rural states in which spatial segmentation between communities is large, modeling fewer specific trip purposes is proposed. In Wyoming, this stratification resulted in two analysis trip purposes for rural statewide planning. This simplification and the results of the interactive modeling procedure illustrate the benefits of a tailored approach to statewide transportation planning for rural states with limited commuter work trips.
Location Translation Within a Geographic Information System
Authors: O’Neill Wende A. , Harper Elizabeth
Published: April 2007

Location translation allows the use of multiple spatial referencing methods within a geographic information system (GIS). Most GIS users are familiar with planar or spherical coordinates expressed as (x, y) pairs of numbers whose values reflect the map projection used. Coordinates are characterized as unique physical locations on the earth’s surface. Transportation professionals have added many methods of referencing data that occur along lines. Linear referencing systems generally reflect a measure of distance from a known point. Common linear referencing methods are route–milepoint and route–reference post–offset. Street (postal) address systems also fall into the category of linear references. Linear referencing methods do not uniquely define locations on the earth’s surface without additional information about the location of the line (or road) on the earth’s surface. Although many of the off-the-shelf GIS systems allow conversion among a wide variety of planar or spherical referencing systems, few accommodate linear referencing systems, and none are capable of translating among linear referencing systems or between planar or spherical and linear systems. Some of the issues that arise in the development of location translation systems are discussed. A description of the data model and database requirements of the system designed for the Utah Department of Transportation is included. This location translation system was developed to facilitate crash reporting in urban areas, although there are numerous applications within transportation agencies.
Monotonic and Cyclic Moment-Inelastic Rotation Behavior for Inelastic Design of Steel Girder Bridges
Authors: Hartnagel Bryan A. , Barker Michael G. , Unterreiner Kara C.
Published: April 2007

Inelastic design of steel girder bridges offers flexibility for innovative bridge structures. The moment-inelastic rotation behavior of interior pier sections is the most important and also the most confusing aspect of the design process. This moment-rotation relation and how it pertains to the service and strength limits of inelastic design are presented. The results of a family of four girder component tests with various properties and expected behaviors are compared with those obtained with theoretical moment-inelastic rotation design models. The fourth of these was subjected to rigorous simulated moving load tests to examine variable repeated loadings. The experimental results matched those obtained with the design models in behavior, and the test moment capacities at the various design levels exceeded those that were predicted. The moving load test showed no degradation of stiffness or strength compared to monotonic loading tests.
Steel-Concrete Composite Columns
Authors: Furlong Richard W.
Published: April 2007

Structural steel shapes and tubes can be used with concrete to produce structural components. The performance of such composite systems, is better than the sum of responses of the parts taken separately. In a concrete-filled steel tube caisson, for example, the steel casing resists flexural tension efficiently while confining the concrete core as the core resists axial compression, whereas it also stabilizes the steel casing. Concrete encasement of structural steel shapes can provide lateral stability to the steel shape, restraining local buckling as well as reducing the slenderness ratio below that of the steel shape alone. Concrete encasement serves as insulation for fire and shock loading. Characteristics of the structural behavior of composite columns are described as the basis for design recommendations. Strength design principles from Load and Resistance Factor Design of the American Institute of Steel and Construction and the American Concrete Institute are used in design. Shear transfer for the effective interaction of concrete and steel is considered, and requirements for transverse bar reinforcement of shear mechanisms are discussed. Design examples of strength estimates for two types of composite columns are included.
Time-Dependent Prestress Losses in Prestressed Concrete Girders Built of High-Performance Concrete
Authors: Lwin M. Myint , Khaleghi Bijan
Published: April 2007

The Washington State Department of Transportation is one of several state departments of transportation involved in demonstration projects to acquire information and data on the design, fabrication, and construction of prestressed concrete bridges with high-performance concrete (HPC). Predicting the time-dependent prestress losses due to the creep and shrinkage of HPC and the relaxation of prestressing steel is difficult because of the limited experience with and data on the creep and shrinkage properties of HPC. The AASHTO load resistance factor design specification approach to estimating prestress losses is discussed, and the time-step method and the modified rate-of-creep method are introduced as ways of predicting more accurately the time-dependent prestress losses. A design example is used to compare and discuss numerically the prestress losses computed by the various methods. The modified rate-of-creep analysis method yields the lowest losses. The modified rate-of-creep method is a desirable, comprehensive, applicable, and practical method for estimating time-dependent prestress losses in composite and noncomposite prestressed concrete girders with HPC. This method is suitable for manual and electronic computation.
Collapse Load Test of 1:3 Shell Bridge Model
Authors: Fanous F. S. , Farmer B. M. , Klaiber F. W.
Published: April 2007

Previous analytical and experimental work by the authors has determined that integrated shell-deck segments can be used to construct short- or medium-span bridges. This system consisted of integrated shell-deck concrete segments that are post-tensioned together to form a simply supported bridge. A 1:3-scale segmental concrete shell bridge model was tested to failure. The bridge model was subjected to increasing load until failure occurred. Before failure, excessive deflection, cracking, and buckling of some of the steel elements connecting the deck to the shell edge beams were observed. Failure of the model resulted from the formation of excessive diagonal shear cracks in the shell portion of one of the segments. The fabrication and the behavior of the bridge model indicated that shell bridges can be used to construct short- and medium-span segmental bridges.
Seismic Design and Retrofit Issues for Bridges in New Jersey
Authors: Saadeghvaziri M. Ala , Rashidi Saeid
Published: April 2007

An overview of guidelines and requirements for seismic design of new bridges and retrofit of existing ones in New Jersey is presented. The results of an ongoing study on seismic assessment of existing bridges in New Jersey are also presented. It is shown that for many older bridges the seismic capacity in the transverse direction is minimal and the bearings can be damaged. However, because of the redundancy of multi-girder bridges, failure of the bearings may not cause collapse of the bridge as long as the columns and piers possess adequate ductility and strength. Circular columns do have adequate lateral reinforcement, but square columns lack the needed ductility demand. In the longitudinal direction, again, failure of the bearings because of shear failure of the bolts is a strong possibility. Unlike in the transverse direction, because of impact and separation of adjacent spans and inadequacy of seat width at the abutments and the tops of piers, loss of span and total failure of the bridge can occur. Therefore, it is important that essential bridges be retrofitted in the longitudinal direction, as proposed. Future research and development needs are also discussed
Causes of Mechanical Damage to Alabama Bridge Decks
Authors: Castaneda Duane E.
Published: April 2007

Excessive damage to Alabama bridge decks that required premature bridge replacements prompted the Alabama Department of Transportation to sponsor an extensive study of the causes of severe deck damage. The mechanical causes of damage, such as the use of slender decks and heavy truck loadings, the magnitudes of service load stresses, and how progressive damage occurs were addressed. Such causes are particularly important for decks constructed in the southern United States, where damage caused by deicing salts and freeze-thaw is not as prevalent as it is in northern U.S. states. To assess the significance of these factors, five damaged decks and five reasonably undamaged decks, as controls, were investigated. Studies conducted on these bridge decks included condition surveys, weigh-in-motion surveys, finite-element analyses, and load tests. The observed damage predominantly consisted of severe transverse cracking at the top surface of the decks. Although restraint of deck shrinkage strains by girders occurred at some of the damaged decks, thus initiating cracking, damage appears to be progressive, and major factors determined from the study to contribute to damage include slender decks, lack of longitudinal reinforcement, aggregate selection, and high axle group loadings.
Role of Dynamic Testing in Assessment of Bridges
Authors: Das P. C. , Owen J. S. , Eccles B. J. , Woodings M. A. , Choo B. S.
Published: April 2007

Six reinforced concrete beams were loaded incrementally up to failure. After each increment the load was removed and measurements of the modal properties of the beams were made by impulse testing. The variation of the natural frequencies, frequency ratios, mode shapes, and the level of damage were investigated. It was found that on completion of the tests the natural frequencies of the beams had been reduced by an average of 25 percent in each mode. However, changes in mode shape were very small, and appreciable differences were only observed when the damage was highly localized. Modeling of the beam by using finite elements predicted trends that compared well with experimental observations. It is concluded that if dynamic testing were used in monitoring reinforced concrete structures, then the changes in frequency due to initial concrete cracking or yield of the reinforcement could be detected. More useful information associated with the spread and type of cracking through a structure may be detectable, although the level of the frequency changes is of the same order as those due to changes in ambient conditions.
Steel Bridge Testing in Alabama
Authors: Conner G. H. , Stallings J. M. , McDuffie T. L. , Campbell J. R. , Fulton R. Y. , Shelton B. A. , Mullins R. B.
Published: April 2007

Interest in nondestructive testing of highway bridges has grown dramatically in recent years. Much of the interest results from the large number of older bridges on state inventories that have posted load limits below normal legal limits. The Alabama Department of Transportation started using load testing to rate highway bridges in 1990 and has since made a significant investment in equipment and personnel in developing the Bridge Rating and Load Test Section. The section provides the capability for many special tests and investigations as well as standard tests for load rating. Insights gained from 46 load tests for bridge ratings are presented to inform other states that are considering the development of load testing capabilities. The procedures used to test and rate steel girder bridges are described.
Structure Movement Systems Approach to Effective Bridge Design
Authors: Burke Martin P.
Published: April 2007

To achieve more effective designs for small- and medium-size highway bridges, bridge designers are urged to view such bridges holistically as structure movement systems instead of elementalistically as a collection of relatively independent structural elements to be shaped and sized to meet only stress, strength, and durability requirements. A number of design examples in which such holistic views were not in evidence and in which movement system components were not recognized as such are presented. Consequently, for these and similar examples, component designs were ineffective and damage- and maintenance-prone structures were the result. It is explicitly recognized that small- and medium-size highway bridges, especially integral and semi-integral bridges, achieve their primary vertical support and longitudinal and lateral stability by being constructed compositely with and functioning in concert with in situ foundation materials, embankments, backfill, pavements, and so forth. Because of the critical importance of such construction, transportation engineers are also urged to recognize that bridges are major components of larger composite structures requiring a multidisciplinary effort to achieve satisfactory designs. Consequently, bridge engineers should cooperate with other transportation engineering specialists to devise and provide more fully effective movement system components, and thus more functional movement systems and more economical and durable structures.
Modular Bridge Expansion Joints for Lacey V. Murrow Floating Bridge
Authors: Van Lund John A. , Kaczinski Mark R. , Dexter Robert J.
Published: April 2007

The Lacey V. Murrow Bridge (LVM Bridge) is a 2013-m-long floating bridge on Interstate 90 across Lake Washington in Seattle, Washington. Single-support-bar, swivel-joist modular bridge expansion joint systems are located at each end of the bridge between the shore approach spans and the floating pontoons. These joints were designed for 960 mm of longitudinal movement as well as horizontal and vertical rotations caused by wind, wave, temperature, and changes in lake level elevation. A similar joint in an adjacent floating bridge had experienced premature fatigue cracking at welded attachment details because of low fatigue strength. For the LVM Bridge the joint components were fatigue tested and designed by using fatigue limit-states loads, resulting in welded attachment details with improved fatigue strength. In addition, a stiffer center beam and reduced center-beam span lengths produced lower fatigue stress ranges. Joint movements and rotations, fatigue design methodology, results of dynamic analyses, field measurements of the dynamic response, and construction details are described. The total cost of the LVM joints was 1 percent of the final bridge cost. The Washington State Department of Transportation required a 5-year guarantee for the LVM joints. These are the largest modular bridge expansion joints in the United States to be tested and designed for fatigue.
Emergence of Semi-Integral Bridges
Authors: Burke Martin P. , Gloyd Charles S.
Published: April 2007

At the 73rd TRB Annual Meeting in January 1994 the paper “Semi-Integral Bridges: Movements and Forces” was presented. It described the attributes, limitations, and peculiarities of a presumably new bridge concept developed by the Ohio Department of Transportation. That presentation elicited a comment from an attendee at the TRB meeting about recent research on a Washington State bridge, a bridge that was later found to be based on this same concept except that it predated Ohio’s earliest prototype by more than 10 years. This discovery of the Washington State experience provoked a state and province inquiry about semi-integral bridge construction, an inquiry that revealed the startling fact that fully 26 state transportation departments have constructed one or more of these structures; some departments have been constructing them for more than 20 years, and two departments have been constructing them for at least 40 years. Another surprising indication of semi-integral bridge experience was the discovery that the design of more than 80 percent of bridges built by two departments are based on the semi-integral concept. Because semi-integral bridges are deck-jointless bridges that can be designed to operate well within usual stress limits, because they are suitable for most moderate-bridge-length applications, because they can be designed to resist the destructive effects of rigid pavement growth and earthquakes, and because so many departments have achieved favorable performance with them, it appears that interest in semi-integral bridges will continue to increase, as will their numbers. However, since the stability of some semi-integral bridges depends to a great extent on composite backfill-structure interaction, future applications of this innovative bridge concept will depend to a great extent on the development of suitable soil-structure interaction research to provide the necessary experimental background to guide future designs.