bluuebunny/crossref_metadata_2025 huggingface dataset:
New Model for Applied University Research and Professional Development: Tren Urbano Program
Authors: Izquierdo-Encarnación José M. , Elena Mercado Lydia , Colucci Benjamín , Salvucci Frederick P. , Wilson Nigel H. M.
Published: April 2007

In preparation for operating its first modern urban rail transit system, Puerto Rico faces the challenge of creating the human resources knowledgeable in rail transit as well as the construction of the physical infrastructure itself. Because a rail transit system takes a generation or more to build, typically over several phases, professional development is aimed at the students currently in college at the start of their careers. Professional development and academic research have been implemented on the Tren Urbano program through technology transfer activities that develop local expertise in rail transit design, construction, and operations; promote research applicable to Tren Urbano and public transportation; and provide real work experience to university students supervised by practicing professionals. These goals have been pursued over the past 7 years through two programs: the Tren Urbano University of Puerto Rico–Massachusetts Institute of Technology Professional Development and Research Program, and the Tren Urbano Student Internship Program. These programs are described and their potential to become a model for applied university research in the public transportation field featuring collaboration between universities, public agencies, and private companies is discussed. Although the initial impetus for the program was driven by the unique Puerto Rican situation, its design, implementation, and evolution have pursued multiple goals that are potentially much more broadly applicable.
Estimating Benefits from Mileage-Based Vehicle Insurance, Taxes, and Fees
Authors: De Corla-Souza Patrick
Published: April 2007

Mileage-based pricing involves variabilization strategies, that is, strategies such as pay-as-you-drive insurance or car-sharing that are aimed at converting the fixed charges for driving to variable charges. They do not directly involve pricing of highway facilities. They nevertheless can reduce congestion by inducing some drivers to change their mode of travel or drive shorter distances. Variabilization strategies are particularly promising since about 80% of the user cost of driving is fixed. Once a vehicle has been purchased and taxes, fees, and insurance have been paid, there is little financial incentive not to use it heavily. How effective are variabilization strategies relative to highway facility-pricing strategies, such as pricing of added highway capacity? The congestion reduction and other economic benefits of policies to variabilize fixed vehicle charges are estimated, and they are compared with conventional highway facility expansion and a pricing strategy involving adding a lane and pricing it for free flow. The analysis suggests that a nationwide variabilization policy that adds 10 cents per mile to the variable user cost of vehicle use (without an increase in total vehicle user costs) could produce a 20-year stream of benefits conservatively estimated at over $44 billion.
Identifying Winners and Losers in Transportation
Authors: Levinson David
Published: April 2007

The issues surrounding transportation equity, both external and internal to transportation, are explored. Several examples are provided of transportation improvements that impose transportation costs on more individuals than those who are benefited. Beyond counting the number of winners and losers, several quantitative measures of equity are suggested and applied to a test case: ramp meters in the Twin Cities, Minneapolis–St. Paul, in Minnesota. It is recommended that transportation benefit-cost analyses include an “equity impact statement,” which would consider the distribution of opportunities to participate in decisions and the outcomes of those decisions (in terms of mobility, economic, environmental, and health effects) that different strata (spatial, temporal, modal, generational, gender, racial, cultural, and income) of the population receive. Policy makers would then have additional information on which to base decisions.
Property Values and Highway Expansion: Timing, Size, Location, and Use Effects
Authors: ten Siethoff Brian , Kockelman Kara M.
Published: April 2007

The effect on commercial property of a major capacity expansion of a roadway facility in Austin, Texas, is examined by analyzing parcel-level real estate assessment data over an 18-year period (1982–1999). A land value model, an improvement or structure value model, and a total property value model were each estimated separately. Since total land values are fundamentally related to parcel acreages and improvement values are related to improvement size, parcel and improvement areas were related to appropriate access variables and structural variables. Empirical results suggest that improvement type, freeway proximity, parcel location at key network points (e.g., corner parcels), and timing of construction and completion play key roles in property valuation. The estimates of impacts should prove very helpful in comprehensive cost–benefit assessments of projects of this nature by public agencies and corridor property owners.
Characterization of Cracking Restraint at Saw-Cut Joints Using the German Cracking Frame
Authors: Vepakomma Shilpa , Jeong Jin-Hoon , Zollinger Dan G.
Published: April 2007

Cracking of concrete slabs at saw-cut notches under a given combination of weather and slab conditions is a major concern in the early stages of construction. Several factors affect crack initiation such as material strength parameters, the method and quality of curing, slab–subbase stiffness, and concrete shrinkage and creep. Early-age creep and shrinkage also appear to be key factors in stress and crack development at the tip of the saw-cut notch. These two factors were analyzed and characterized by experiments that provide some insight relative to how shrinkage and creep strain affect crack development. These results can be useful in evaluating the behavior of concrete and the development of cracking at saw-cut notches. The German cracking frame was used to provide restraint and the means to initiate cracking at an artificial notch during early-age strength development in the concrete while the concrete was undergoing creep and shrinkage strains. The cracking frame tests were conducted under constant temperature and relative humidity conditions in the laboratory. A fracture mechanics approach was followed to determine concrete strength at the saw-cut notch. It can be concluded that the development of creep strain in the concrete affects the cracking tendency of the concrete. The data seemed to suggest that a greater cracking tendency at the saw-cut notches did not result until after the incremental creep strain in the concrete had diminished sufficiently. The role of creep and shrinkage under field conditions relative to the control of cracking due to saw cutting in newly constructed concrete slabs is also considered indirectly.
Evaluation of New Nonnuclear Pavement Density Gauges with Data from Field Projects
Authors: Romero Pedro , Kuhnow Frederick
Published: April 2007

The introduction of new devices to measure pavement density requires an evaluation method that is both accurate and fair. Evaluations are commonly done by taking a density measurement with the gauge and comparing this density to the density obtained from a core taken at the same location. This approach must meet two requirements; first, enough cores must be taken at each location to make the comparisons meaningful, and second, evaluation of these devices must be done with as many projects in as many locations as possible to account for all materials used in pavement construction. Unfortunately, given the difficulties in obtaining field cores, large numbers of cores that can be used for evaluations are not available from all projects. Therefore, any evaluation of density gauges must balance rigor with practicality. The correlation coefficient was selected to evaluate the new nonnuclear pavement density gauge. However, because only a limited number of cores are available at each site for development of the correlation coefficient, this parameter by itself cannot be used to evaluate the new gauge. Instead, results from side-by-side comparisons with the accepted nuclear density gauge were used to aid in the evaluation of the new density-measuring device. It was concluded, on the basis of data from 76 projects in six different states, that the proposed nonnuclear density gauge must be further developed before it can be used to determine pavement density. In its current form, the densities obtained with the device do not correlate with the measured densities to the same degree that the densities measured with existing devices do. Use of this nonnuclear device will introduce more uncertainty in pavement density measurements than that which already exists.
Application of Profile Data to Detect Localized Roughness
Authors: Fernando Emmanuel , Bertrand Carl
Published: April 2007

The application of profile data to detect areas of localized roughness is illustrated. The approach presented is based on the deviations of the profile from the moving average coupled with the use of a smoothness statistic, computed from the profile, to estimate the change in pavement smoothness with correction of surface irregularities. In this way, the significance of a surface defect is evaluated on the basis of its contribution to the overall roughness of a pavement section. The approach is illustrated by using profile data from an in-service pavement. By simulating the response of the profilograph to the measured profile, the peak deviations from the moving average were observed to track the bump locations from the simulation.
Evaluation of Eight Longitudinal Joint Construction Techniques for Asphalt Pavements in Pennsylvania
Authors: Kandhal Prithvi S. , Ramirez Timothy L. , Ingram Paul M.
Published: April 2007

Premature deterioration of multilane hot-mix asphalt pavements can occur at the longitudinal joints in the form of cracking and raveling. The National Center for Asphalt Technology initiated a national study that evaluated various longitudinal joint construction techniques in 1992 in an effort to select the technique(s) that improves the performance of longitudinal joints. Test sections were constructed in Michigan, Wisconsin, Colorado, Pennsylvania, and New Jersey. The 6-year performance evaluation of eight different techniques used on a paving project in Pennsylvania in 1995 is provided. In Pennsylvania, longitudinal joint constructed with rubberized joint material gave the best performance, closely followed by the joint made with a cutting wheel. Test sections on which rolling from the hot side 152 mm away from the joint and the New Jersey wedge joint were used also performed reasonably well, with no significant cracking. The remaining four test sections on which the edgerestraining device, joint maker, rolling from the hot side, and rolling from the cold side were used developed cracking at the longitudinal joint to different extents. It has been recommended that the minimum compaction level at the longitudinal joint be specified to ensure its improved performance.
Virginia’s Experience with 9.5-mm Nominal-Maximum-Aggregate-Size Stone Matrix Asphalt
Authors: Prowell Brian D. , Allen Cooley L. , Schreck Richard J.
Published: April 2007

Construction data from two Virginia stone matrix asphalt (SMA) field projects that used 9.5-mm nominal-maximum-aggregate-size (NMAS; Superpave® definition) gradations are presented. Analyses were conducted to evaluate breakpoint sieve size, rut resistance, design compaction effort, and permeability. Rut resistance and permeability results for 9.5-mm NMAS mixes were compared with those for more conventional Virginia 19.0- and 25.0-mm NMAS SMA mixes produced by the same contractor and with the same aggregate source. A sieve size of 2.36 mm was confirmed as being the appropriate breakpoint for 9.5-mm NMAS SMA. For this gradation, 9.5-mm NMAS SMA with both performance-graded binder (PG) 70-22 and PG 76-22 was as rut resistant as previous Virginia SMA mixtures, as tested with the Asphalt Pavement Analyzer. The data for these sections indicate that 9.5-mm NMAS SMA should be designed with 75 gyrations instead of the currently recommended 100 gyrations. SMA with a 9.5-mm NMAS was also shown to be less permeable at the same air void level as the more commonly used 19.0- and 25.0-mm NMAS SMA.
Establishing Variability for Hot-Mix Asphalt Construction in Arkansas
Authors: Hall Kevin D. , Williams Stacy G.
Published: April 2007

The Arkansas quality control/quality assurance (QC/QA) specification for hot-mix asphalt (HMA) construction was initially developed from data and experience gained with the Marshall method of mix design. The implementation of Superpave®, coupled with the initiation of the largest asphalt construction program in the state’s history, resulted in questions relating to the suitability of the QC/QA specification. Research was undertaken to revise the existing program or create a new specification. The first step in the effort was to establish typical HMA construction variability in terms of the pay factors used in Arkansas: air voids, voids in the mineral aggregate, binder content, and field density. Six projects were randomly sampled and tested by three operators: the contractor, the agency, and the research team. Six specimens were prepared by each operator at each of four testing times within each project. The results of the testing showed that the six projects bracketed a wide variation in mixture quality as defined by the HMA properties. The testing data were normally distributed, validating a typical assumption regarding construction. Analyses showed that the testing variability among the three operators could be absorbed into the overall variability of test properties instead of being considered a distinct factor. Three levels of HMA quality were identified by the mean and standard deviation of the test data. These quality levels are expected to form the basis for any revision to the existing QC/QA system or for the development of a new QC/QA system for Arkansas HMA construction.
Variability of Concrete Materials Data in Long-Term Pavement Performance Program
Authors: Tayabji Shiraz D. , Wu Chung-Lung
Published: April 2007

As part of a study sponsored by NCHRP, research was conducted to evaluate the variability of concrete materials data in the Long-Term Pavement Performance (LTPP) program. The following materials-related data were studied: ( a) compressive strength, ( b) flexural strength, ( c) split tensile strength, and ( d) modulus of elasticity. The variability was determined in terms of the standard deviation and coefficient of variability. The strength and stiffness data used came from the General Pavement Study (GPS) as well as the Specific Pavement Study (SPS) test sections. The analysis of data indicates that, in general, the LTPP program GPS test sections as well as the LTPP program SPS test sections exhibit characteristics of well-controlled construction projects with respect to the strength- and stiffness-related properties of concrete. The results of the analysis indicate that on well-controlled concrete pavement construction projects it would not be unreasonable to produce concrete that has a coefficient of variation of 15% or less for compressive strength, flexural strength, split tensile strength, and the modulus of elasticity. The findings from the analysis can be used to refine statistics-based quality assurance/quality control procedures for concrete acceptance and to define the measures of variability to be used in mechanistically based concrete design procedures.
Analysis of TransTech Model 300 Pavement Quality Indicator: Laboratory and Field Studies for Determining Asphalt Pavement Density
Authors: Hausman John J. , Buttlar William G.
Published: April 2007

The pavement quality indicator (PQI) produced by TransTech Systems, Inc., uses principles of electrical impedance and the dielectric constants of materials to determine the densities of asphalt pavements. The Model 300 PQI device was recently evaluated in Illinois as a potential alternative to nuclear density gauges for quality control/quality assurance of asphalt pavement construction. Both laboratory and field testing were conducted to meet these objectives. The PQI has several appealing features relative to the nuclear density gauge, including its light weight and rapid operation in the field without the need for special licensing, handling, or training. The density determined with the nuclear density gauge generally exhibited a closer correlation with the density determined from pavement cores, as denoted by significantly lower squared error of the regression values in the regression analyses performed. Also, although the Model 300 PQI has been improved from earlier models to account for moisture and temperature, the data suggest that the device is still influenced by environmental conditions. On the other hand, the PQI proved to be more operationally convenient for the field technician, being significantly lighter and less time-consuming to operate in the field. On the basis of analysis of the information obtained from the studies, the Illinois Department of Transportation has chosen to base acceptance and statistical pay factors on density values obtained by the AASHTO T166 method with pavement cores. At present, the nuclear density gauge is still the specified device for quality control/quality assurance of asphalt pavement projects in Illinois.
Smoothness Provision for Bridge Decks
Authors: McGhee Kevin K.
Published: April 2007

A contemporary survey of bridge ride quality is described, and use of the survey to support the development of a modern smoothness provision for bridge decks is discussed. The survey found that bridges have an average of 60% more roughness than most mainline highway pavements [as measured by use of the international roughness index (IRI)]. However, a secondary analysis revealed that beam and girder camber can easily contribute more than 1000 mm/km of additional IRI roughness, which suggests that IRI may not be an equitable tool for measurement of the construction quality of bridges. This finding led to an additional analysis that focused on the use of a simulated rolling straightedge as a tool to control smoothness. Ultimately, the study demonstrated how inertial (and high-speed) profiling equipment can be applied to control bridge deck roughness through the use of a simulation that mimics the traditional 3-m straightedge.
Grouting of Segmental Posttensioned Bridges in America
Authors: Pielstick Brett H.
Published: April 2007

Over the past several years the posttensioned concrete bridge industry in America has experienced several tendon failures because of corrosion. These isolated failures resulted in the conduct of additional investigations in Florida as well as several other states. Those investigations have determined that several structures have shown grouting deficiencies. Some of the areas with grouting deficiencies had voids with no corrosion present, but others showed corroded ducts and posttensioning strands. As a result, the owners and the industry have evaluated the process of grouting and have developed a course of action to improve the grouting and thus the long-term durabilities of these structures. The Post-Tensioning Institute Specification for Grouting of Post-Tensioned Structures, The Concrete Society Technical Report 47, as well as the American Segmental Bridge Institute (ASBI) Interim Statement on Grouting Practices address several areas in which the grouting process can be improved. First, several design details have been changed to improve the recharge characteristics and performance of the posttensioning systems. Second, several changes to the grout material have been recommended. The use of antibleed or no-bleed grouts is recommended, and in Florida the use of such grouts is required. Third, improvement of the grout equipment will provide a consistent mix and density for the grout. Fourth, it was recommended that training and certification for grouting technicians and inspectors be required. ASBI and the Florida Department of Transportation have created training and certification programs for inspectors and grouting technicians. Although no structural deficiencies on segmental posttensioned bridges in America have been noted to date, the industry has mobilized to address the grout problems to further enhance the durabilities of these structures.
Infrared Thermographic Analysis of Bridges: Case Study
Authors: Clark M. R. , McCann D. M. , Forde M. C.
Published: April 2007

Infrared thermography has various applications within civil engineering areas. One such application was explored. A survey was carried out to investigate the presence of temperature anomalies that may indicate the existence of delaminations on the underside of a concrete bridge deck. A case study investigating a number of bridge spans from the ground by an infrared survey is reported. The brief required an infrared thermographic survey of Span 5 of the bridge. In the event, however, the technique was so time efficient that infrared and visual images were taken over five spans, with concentration on one span in which there were known areas of delamination. The known areas of delamination were found, as were a number of other areas of possible delamination. The delaminations were found by the infrared thermographic survey despite the worst possible ambient temperature conditions and even though the infrared camera could not be positioned far enough away to survey the entire span at the same time.
Issues Related to Use of Contractor Quality Control Data in Acceptance Decision and Payment: Benefits and Pitfalls
Authors: Killingsworth Brian M. , Hughes Chuck S.
Published: April 2007

Several agencies throughout the United States use contractor data as a means of acceptance. This is a permissible practice as long as certain safeguards are in place and as long as the functions of quality control and quality acceptance remain separate. The benefit of this type of procedure is potential decreases in the personnel and testing facilities required by the state agency. However, this type of approach for acceptance also has inherent risks. In most cases, the changes required to implement a system in which contractor data are used in the acceptance decision are more philosophical than technical. In other words, the amount of testing that the contractor will have to do to meet the requirements of the change will more than likely be about the same as (or only slightly more than) that undertaken in the current specification system. However, even though a state agency may see a drop in the amount of testing required to support acceptance, it will now be faced with the fact that it must trust the contractor’s data for determination of pay factors and, ultimately, acceptance of the work. Thus, when the procedure of contractor testing used for acceptance is fully implemented, there will be two major impacts on a state agency. One is a psychological adjustment for agency personnel to assimilate the fact that contractor test results will be used to establish the pay factor. Discussion is needed to address this adjustment, and the state should plan training sessions to address the reasons for this decision and the importance of the steps that will be taken to implement it. The other impact will be the need to implement and monitor the validation system.
Contractor-Led Quality Control and Quality Assurance Plus Design—Build: Who Is Watching the Quality?
Authors: Ernzen Jim , Feeney Tom
Published: April 2007

Recent innovations by the Arizona Department of Transportation (DOT) in the use of design—build procurement for highway construction are presented. Explosive population growth in Arizona has pushed its DOT to the limits of its capacity and has challenged the department to develop innovative ways to stretch its resources to meet its constituents’ needs. In 1996 the department spearheaded the passage of a pilot design–build law aimed at completing public-sector construction projects more rapidly than could be done by traditional methods. An evaluation of the material quality program used in the second design–build project in this program is described. The project reconstructed an extremely congested 7-mi segment of Interstate 17, a primary artery carrying 180,000 vehicles per day through the city of Phoenix, widening it from 6 to 10 lanes. The design–build contract was awarded after A+B bidding, which considered the bid price to do the work and the time required to complete the project, and was the largest ever awarded at the time. It was won by a design–builder who implemented a very aggressive schedule that required double-shift work for nearly 2 years. In another contracting first, the agency also assigned the design–builder responsibility for the quality control and quality assurance functions on the project, with Arizona DOT providing verification sampling and testing only. The concrete compressive strength and material density for the project are examined and are compared to statewide averages for traditional design-bid-build projects in which Arizona DOT performed the quality assurance function. Analysis of the data shows that despite a highly compressed schedule, the quality of the material on the project exceeded the project specifications and was similar to the quality of work completed for the state under traditional contracting methods with an Arizona DOT—operated quality assurance program.
Quality-Based Prequalification of Contractors
Authors: Hancher Donn E. , Lambert Sean E.
Published: April 2007

The results of research performed for the Kentucky Transportation Cabinet on the development of a quality-based prequalification system for contractors desiring to do work for the cabinet’s Department of Highways (DOH) are reported. For many years Kentucky has had a formal contractor prequalification system that establishes both the type of work that a contractor may perform for DOH and the maximum dollar volume of work that the contractor can do, including work done for other clients, at one time. It was desired to strengthen the weight given to work quality in the prequalification analysis. A new performance evaluation was developed for highway engineers to evaluate the performance of contractors on projects. This will be done annually for all projects or at the end of the project if it is completed before the end of a year. The contractor is given a copy of the annual evaluation and can appeal the rating. A summary rating is calculated for each contractor and subcontractor and is based on the performance ratings for all projects that the contractor and subcontractor worked on for DOH during the year. This overall rating is used in the prequalification process to determine the amount of work that will be allowed in the coming year. Lower-quality work will reduce the allowable work volume, whereas high-quality work will increase the allowable work volume. There is also an appeals process for the final work volume limit set each year. A new performance evaluation was also developed to allow the contractor to evaluate the performance of DOH on a project each year. DOH will use this information to improve its processes and to develop training for its personnel.
Quality Management System for a Highway Megaproject
Authors: Mrawira Donath , Rankin Jeff , John Christian A.
Published: April 2007

Although the concepts of quality management have been successfully applied in many industries, primarily manufacturing, and are equally applicable to the construction industry, highway megaprojects, especially those delivered through private–public partnership (P3) arrangements, present new challenges. The current movement from the use of traditional method specifications to the use of end-result specifications and the transfer of responsibilities for quality to the developer and builder give rise to the need to verify quality performance. A quality information management system becomes a necessity given the volume of information generated. The challenges of developing and implementing a quality information management system for a highway megaproject in New Brunswick, Canada, are discussed. The system developed addresses key needs including support for various levels of management (technical and executive), an open data structure and interoperability, hierarchical information levels, integration with facilitywide management information, and future scalability. The system developed addresses the needs of quality information management for a private project developer but can also be adapted to other project delivery mechanisms. The tool was implemented to support the entire project team, including construction field supervisors and the project’s senior management. A documented analysis is offered of a generic implementation process that can be adopted in other projects to improve efficiency in quality information management in the highway construction industry in general and in megaprojects delivered through P3 arrangements in particular.
Construction Productivity Analysis for Asphalt Concrete Pavement Rehabilitation in Urban Corridors
Authors: Lee Eul-Bum , Harvey John T. , William Ibbs C. , St. Martin Jim
Published: April 2007

The results of a constructibility and productivity analysis for the California Department of Transportation Long Life Asphalt Concrete Pavement Rehabilitation Strategies program are presented. With the assistance of California asphalt concrete (AC) paving contractors, the analysis explored the effects on construction productivity of rehabilitation materials, design strategy (crack seat and overlay, full-depth replacement), layer profiles, AC cooling time, resource constraints, and alternative lane closure tactics. Deterministic and stochastic analysis programs were developed. A sensitivity study that examined the construction production capability within a 55-h weekend closure was performed. Weekend closures were also compared with continuous closures. Demolition and AC delivery truck flows were the major constraints limiting the AC rehabilitation production capability. It was concluded from the study that efficient lane closure tactics designed to work with the pavement profile can minimize the nonworking time to increase the construction production efficiency. The results of the study will help road agencies evaluate rehabilitation strategies and tactics with the goal of balancing the maximization of production capability and minimization of traffic delay during urban pavement rehabilitation.
Evolution of Contractor’s Construction Schedule to Meet Engineer’s Satisfaction
Authors: Abdul-Malak Mohamed-Asem U. , Hassanein Zeina A.
Published: April 2007

With the increasing complexity of construction projects, proper planning and control of project activities now represent key issues in the management function. Pre-tender planning leading to a cost estimate is normally used as a baseline for project control in the subsequent project stages. That is, construction planning and cost estimation are done in parallel to reach a realistic cost estimate. However, not enough scheduling can be done at the tender stage because scheduling requires a certain level of detail for the work items. It is proposed that the misconception that the contractor is able to submit a full-fledged detailed construction schedule on awarding of the contract, followed later by regular updates, be replaced with a rolling-wave concept that permits work items with different levels of detail to be shown simultaneously in any version of the schedule. A procedure for generating the first construction program and gradually developing it during the construction phase is proposed. This procedure is aimed at allowing engineers and contractors the opportunity to understand the intrinsic principles for proper administration of the construction schedule.
Factors of Importance for Determining Daytime Versus Nighttime Operations in Oregon
Authors: Park Sang-Bin , Douglas Kimberly D. , Griffith Andrew S. , Haas Kevin J.
Published: April 2007

The state of Oregon is in the process of developing a decision model that will be used to improve the decision-making process concerning daytime versus nighttime construction and maintenance activities. In reviewing the literature, a comprehensive list of factors was available that was well defined and articulated. However, the literature did not provide information on the relative importance of the various factors. The findings from the literature review and the results from an extensive survey are provided. The survey details the views of 446 respondents from within the state of Oregon and 25 other states. Congestion, traffic control, and safety were the most important factors in making these decisions.
Using a Handheld Computer to Provide Documentation for Construction and Maintenance of Transportation Infrastructure
Authors: Williams Trefor P.
Published: April 2007

Handheld computers can be used to provide electronic reference manuals of transportation infrastructure construction and maintenance information. With the addition of wireless modems, these devices are able to capture information from the World Wide Web and make it available at remote construction sites. Three prototype applications have been developed for a Palm VII handheld computer. One is a web clipping application that retrieves New Jersey Department of Transportation (New Jersey DOT) construction specifications from a website. Palm web clipping applications are written in hypertext markup language. A second application demonstrates how large text documents can be converted to electronic books for use on Palm devices. This application used iSilo software to incorporate New Jersey DOT specifications and construction procedures. The third application uses the FireViewer suite of programs to provide a prototype system of reference documents and educational materials related to highway maintenance activities. The FireViewer suite of programs allows a Palm device both to access web pages in real time and to download and save material from the web. The applications developed illustrate the potential for using handheld computers as electronic reference manuals and as a means of accessing the World Wide Web in the field. The limited capabilities of Palm devices to display graphics and the cost of transmitting data wirelessly indicate that simple web pages should be developed for use with handheld computers. As the devices become more powerful, more elaborate systems of documents and drawings can be constructed for use in the field.
Forensic Investigation of Failed Mast Arms of Traffic Signal Supported Structures
Authors: Chen Genda , Barker Michael , MacKenzie D. Scott , Ramsay Christopher , Alderson Joe , Dharani Lokeswarappa , Yu Jiaqing
Published: April 2007

In Missouri, 11 traffic signal mast arms fractured at the arm-post weld connection in 7 years. To reduce this fatigue failure, the Missouri Department of Transportation developed a fatigue-resistant weld profile that increases the weld leg and reduces the slope of the weld at the toe. This study investigated causes of the failed arms, compared performance of new and old weld profiles, and suggested retrofitting measures for further investigation. The scope included a metallurgical investigation of one failed field mast arm, laboratory fatigue testing of five prototype mast arms (two new and three old profiles), and laboratory failure analysis of one arm tested to cracking. Metallographic and fractographic analyses indicated that the fatigue crack in the failed mast arm initiates near the weld toe of the arm due to undercutting, creating a sharp local toe angle. Location of undercutting at the heat-affected zone of the base material, where the material is softest, further contributed to early fatigue failure. Tests showed that the new weld profile does not consistently increase fatigue strength. Premature fracture surfaces of one tested arm indicated that the fatigue cracks initiate in an area at the weld toe as observed in the failed mast arm. Therefore, changing the weld profile alone is unlikely to increase mast arm fatigue life. Pinning the weldment surface at the weld toe of mast arms is suggested to increase the life of mast arms.
Predicting Deflections in Concrete-Filled Grid Deck Panels
Authors: Mangelsdorf C. P. , Baker Tod H. , Swanson James A.
Published: April 2007

Laboratory test results from six different concrete-filled steel-grid bridge deck panels of one and two spans with approximate midspan loadings were compared with finite difference solutions of a governing differential orthotropic plate equation. The orthotropic plate equation was based on assumptions related to fully composite behavior. The effects of changes in properties due to increasing loads were examined. A means of predicting deflections in other laboratory panels was developed, and the results were extended to permit the estimating of deflections in actual bridge decks.
Effect of Diaphragms on Load Distribution of Prestressed Concrete Bridges
Authors: Cai Chun S. , Shahawy Mohsen , Peterman Robert J.
Published: April 2007

Load testing results for six prestressed concrete bridges were used to evaluate analytical methodologies. The bridges have different span lengths, number of lanes, and skew angles. Maximum strains and load distribution factors predicted by finite element analyses and AASHTO code specifications were compared with those from measurements. This comparison indicated that the diaphragm stiffness of the bridges examined is uncertain due to possible concrete cracking and weakness of the diaphragm-girder connection. Ignoring or considering low diaphragm stiffness gives better strain distributions across the bridge width than considering the full diaphragm stiffness, compared with the test measurements. Sensitivity study revealed that the diaphragm stiffness has significant effects on bridge strains and their distributions. It is important, though difficult, to choose a reasonable diaphragm stiffness in analytical analysis. Theoretically, full diaphragm stiffness can be achieved by posttensioning the diaphragm across the bridge width. If the full diaphragm stiffness does exist, the maximum strain and load distribution factor can be significantly reduced.
Intermediate Diaphragm and Temperature Effects on Concrete Bridge Performance
Authors: Green Tanya , Yazdani Nur , Spainhour Lisa , Cai Chun S.
Published: April 2007

A study was conducted to determine the effects of intermediate diaphragms on bridge superstructure performance, combined with actual bearing stiffness and thermal changes. Parameters studied included the presence of intermediate diaphragms, rises and drops in temperature, and increase in bearing stiffness. A finite element model of a bridge superstructure containing Florida Bulb Tee 78 girders was created using ANSYS software. This model was subjected to HL93 truck load as suggested by the AASHTO load and resistance factor design specifications. The results indicate that intermediate diaphragms have the positive effect of reducing the maximum deflections and stresses for the bridge system. The expansion of the bridge due to a positive temperature change was shown to decrease midpoint deflections, and vice versa. The combined effect of intermediate diaphragms and temperature changes increases the effect brought about by the temperature changes.
Prediction of Settlement in Existing Tunnel Caused by the Second of Twin Tunnels
Authors: Cooper Michael L. , Chapman David N. , Rogers Christopher D. F. , Hansmire William
Published: April 2007

In 1994 to 1996, three 9-m-diameter parallel tunnels were constructed crossing below twin existing tunnels at London Heathrow Central Terminal Area station for the Heathrow Express project at Heathrow Airport in the United Kingdom. Extensive monitoring was undertaken during construction. Settlement curves at various construction stages in the existing tunnels were measured. Marked asymmetry was noted in the settlement curves caused by construction of the two outer tunnels. It has been noted by several authors that the surface settlement trough caused by the second of two closely spaced tunnels is markedly asymmetrical. This has been accounted for by the fact that when twin tunnels are closely spaced, the ground in the region where the second tunnel is to be constructed has already been subjected to appreciable shear strains associated with construction of the first tunnel. This reduces ground stiffness, hence a higher volume loss for the second tunnel, producing an asymmetrical settlement trough with settlements greater on the side nearest to the first tunnel. The data from London Heathrow have been added to a database of case histories of twin tunnels prepared from reported information worldwide. A new empirical method was developed for estimating the settlement trough caused by the second of twin tunnels, along with an exercise demonstrating the use of the method, which is proposed for use as a preliminary predictive tool.
Safety Aspects of Flexible New Austrian Tunneling Method Versus Stiff Shotcrete Linings
Authors: Launay Jean
Published: April 2007

When driving large underground cavities such as metro stations in urban areas, the method of excavation and the type of lining must be adjusted to minimize the surface movements. Two approaches can be envisaged—a flexible lining or a stiff lining. These two approaches can be associated with the original new Austrian tunneling method (NATM) concept (flexible lining) and the sprayed concrete lining (or stiff lining). On the basis of the historical background and definition of these two concepts, typical site movements encountered at two underground stations located under the same soft rock conditions were studied. A theoretical analysis was undertaken to try to explain the reasons why the interaction rock lining support behaves in the way observed.
Risk Management: Illustrated Contribution of Insurers and Reinsurers
Authors: Porro Bruno , Schaad Werner
Published: April 2007

The role of risk management in complex infrastructure projects from the reinsurer’s standpoint was examined, along with the risk assessment and rating techniques for various engineering disciplines. Risk management includes the implementation of project-specific management and monitoring techniques and contingency planning throughout the entire project duration. Machines, equipment, and building technology undergo rapid development. Insurance plays a vital part in supporting innovation, but an appropriate balance must be attained between retained entrepreneurial risk and transferred trade risk.
Development of New Small-Diameter Drainage Pipe
Authors: Brockenbrough Roger L.
Published: April 2007

Over the past few years, a new small-diameter pipe has been developed for storm water drainage, culverts, and similar applications. The product is manufactured from polymer-coated galvanized steel by the helical lock seam process on a new line of equipment developed for that purpose. Known as PolyRib pipe, the profile is composed of sets of three closely spaced ribs with a wider spacing between the sets of ribs to accommodate the lock seam. As part of the process for evaluating the new product, tests were conducted that included hydraulic tests, soil box tests, installation tests, pipe stiffness tests, beam tests, and durability tests. The results of these investigations are summarized. New ASTM standards may be used to design and specify the product. Procedures for determining sectional properties and a table of maximum fill heights have also been developed. Evaluation of the information shows that the product has the required attributes to provide a competitive new drainage pipe for moderate fill heights in the small-diameter market.
Factors for Rating Condition of Culverts for Repair or Replacement Needs
Authors: Cahoon Joel E. , Baker Dan , Carson Jodi
Published: April 2007

Many aspects of transportation infrastructure have benefited from the use of full-scale management systems to quantify condition and predict useful life estimates. Although culvert management models have been tested in the past, none has proven functional. In this study, a condition rating system for culvert repair or replacement was developed. Parameters that describe the condition of an existing culvert were tested for potential as predictors of overall culvert condition. These 33 parameters were recorded at 460 culverts distributed geographically throughout Montana. An ordered probit statistical model indicated that 9 of the initial 33 potential predictors were statistically significant. Measurements of these nine parameters can be used in the resulting model to classify a culvert into a 1-to-5 condition ranking, in which 5 is the best condition and 1 is the worst.
Finite-Element Modeling of Reinforced Concrete Arch Under Live Load
Authors: McGrath T. J. , Mastroianni E. P.
Published: April 2007

Full-scale field tests were conducted on two 8.5-m (28-ft) span reinforced concrete arch culverts. The culverts were subjected to service live loads at depths of cover from 0.3 to 0.9 m (1 to 3 ft). At 1 ft of fill, the culverts were loaded with a simulated single-axle live load greater than 980 kN (220,000 lb). Field data collected included arch deflection, interface pressure, concrete strain, and reinforcing strain. The computer modeling of the live-load tests is reported. Two- and three-dimensional finiteelement analyses were conducted. Nonlinear material models were used for the backfill soil and the reinforced concrete in both the two- and three-dimensional analyses. Results from the finite-element analyses are compared with the field test data. Results of this study indicate that the two-dimensional models are limited in their ability to predict the longitudinal spreading of live load forces in the culverts and to predict maximum moments larger than those in the actual structure. The three-dimensional finite-element deflection predictions were dependent on the properties used to define the concrete material model; however, the design forces (moment, thrust, and shear) did not show the same sensitivity. This indicates that for typical structural design, material parameters may be approximated without seriously degrading the accuracy of predicted design forces. The test structures met AASHTO design criteria for strength and serviceability.
Concrete Bridge Decks Constructed with Fiber-Reinforced Polymer Stay-in-Place Forms and Grid Reinforcing
Authors: Dieter David A. , Dietsche Joshua S. , Bank Lawrence C. , Oliva Michael G. , Russell Jeffrey S.
Published: April 2007

A description is given of laboratory testing, initial test results, and continuing research to develop design procedures and plans for construction of a two-span highway overpass on US-151 in the state of Wisconsin using only a fiber-reinforced polymer (FRP) reinforcement system in the concrete bridge deck. The use of FRP reinforcing is being pursued to increase the durability of bridge decks and to reduce unit cost and time. The unique aspect of the new bridge is that it will use FRP stay-in-place formwork, placed over precast concrete I girders, to serve as formwork and as the bottom transverse reinforcement of the bridge deck. In addition, a heavy-duty prefabricated FRP grid will be used for the top layer of concrete reinforcing. Full-scale prototype laboratory testing is being used to develop design recommendations including effective distribution widths. From the spring to fall of 2003, a construction productivity study comparing the FRP deck construction sequence with that of identical adjacent steel reinforced deck will be conducted. Both bridges will be field load tested before opening to traffic. The FHWA Innovative Bridge Research and Construction Program is supporting the research and construction.