A közlekedésépítési szakterület mérnöki és tudományos folyóirata. ISSN 2064-0919
11. szám
2018 ősz
11
Bejegyzés

Nemzetközi szemle: Január

Aszfalt pályaszerkezet tervezési anyagválasztási útmutató

Material Selection Guidance for Asphalt Pavement Design

Szerzők: C. Rodezno, D. Timm, M. Robbins, N. Tran  ( National Center for Asphalt Technology USA )


Kivonat:

Over the years, the asphalt industry has developed and quickly adopted a number of innovative and sustainable materials and technologies (hereinafter referred to as materials) for use in flexible pavements. While sustainability is a broadly‐used term, within this report it refers to the usage of specific materials meant to reduce the consumption of virgin raw materials or otherwise reduce the carbon footprint of asphalt mixture production. Specific examples of these sustainable and innovative materials include warm mix asphalt (WMA), recycled asphalt shingles (RAS), reclaimed asphalt pavement (RAP), recycled tire rubber (RTR), stone matrix asphalt (SMA), and cold recycled mixtures. These materials offer economic, engineering, and environmental advantages over conventional materials when their use in structural pavement design is carefully considered to arrive at optimized structures. The purpose of this document is to provide guidance for flexible pavement design methods to arrive at optimized pavement structures when innovative and sustainable materials are used, and also to identify the challenges when trying to incorporate these materials. This report also provides a basic understanding of different materials and technologies, mix design considerations, material properties, performance, and possible applications.

A hosszú távú hídviselkedés és a forgalom előrebecslése nagymennyiségű adattal – számítástechnikai keret fejlesztése

Development of a Computational Framework for Big Data-Driven Prediction of Long-Term Bridge Performance and Traffic Flow

Szerzők: I. H. Cho, A. Chen, A. Alipour, B. Shafei, S. Laflamme, I. Song, J. Yan  ( Iowa State University USA )

Terjedelem:  52 oldal

Kivonat:

Consistent efforts with dense sensor deployment and data gathering processes for bridge big data have accumulated profound information regarding bridge performance, associated environments, and traffic flows. However, direct applications of bridge big data to long-term decision-making processes are hampered by big data-related challenges, including the immense size and volume of datasets, too many variables, heterogeneous data types, and, most importantly, missing data. The objective of this project was to develop a foundational computational framework that can facilitate data collection, data squashing, data merging, data curing, and, ultimately, data prediction. By using the framework, practitioners and researchers can learn from past data, predict various information regarding long-term bridge performance, and conduct data-driven efficient planning for bridge management and improvement. This research project developed and validated several computational tools for the aforementioned objectives. The programs include a data-squashing tool that can shrink years-long bridge strain sensor data to manageable datasets, a data-merging tool that can synchronize bridge strain sensor data and traffic flow sensor data, a data-curing framework that can fill in arbitrarily missing data with statistically reliable values, and a data-prediction tool that can accurately predict bridge and traffic data. In tandem, this project performed a foundational investigation into dense surface sensors, which will serve as a new data source in the near future. The resultant hybrid datasets, detailed manuals, and examples of all programs have been developed and are shared via web folders. The conclusion from this research was that the developed framework will serve practitioners and researchers as a powerful tool for making big data-driven predictions regarding the long-term behavior of bridges and relevant traffic information

Kétsávos utak kapacitásának és üzemelési teljesítményének javított elemzése

Improved Analysis of Two-Lane Highway Capacity and Operational Performance

Szerzők: S.S. Washburn, D. Watson, Z. Bian, A. Al-Kaisy, A. Jafari, R. Dowling, A. Elias, T. Luttinen (University of Florida, Montana State University, Kittelson and Associates, Inc. USA, Aalto University, Finland)

Terjedelem: 679 oldal

Kivonat:

Two-lane highways account for a very significant portion of the national highway system and serve an essential function for the movement of people and goods. The Highway Capacity Manual HCM) contains a chapter that provides an analysis methodology for two-lane highways. Unfortunately, the current HCM analysis procedure has been criticized on several issues, such as the speed-flow relationship, appropriate service measures, treatment of large trucks, guidance on base free-flow speed estimation, accuracy of passing lane adjustments, and limitations in analysis scope. This project sought to address these limitations and gaps. Accomplishments from this project include the following: the development of a more realistic speed-flow relationship; the introduction of a new service measure—follower density; a new headway threshold value to better identify follower status; development of a percent followers flow relationship; elimination of passenger car equivalent (PCE) values and direct use of percentage of heavy vehicles in the models for performance measure estimation; the inclusion of a quantitative adjustment based on posted speed limit for the estimation of base free-flow speed (BFFS); the development of new functions for passing lanes—effective and optimal lengths and performance measure improvements for 2+1 sections; and the development of a method for combining the analysis of multiple contiguous segments into a facility-level analysis. This project also introduced features to improve the ease of use of the methodology in the HCM, such as elimination of tables requiring interpolation, treating trucks explicitly instead of through PCE values, using a single service measure, and eliminating the PTSF measure. And finally, two modern microsimulation tools were identified that are capable of accurately modeling two-lane highways: SwashSim and TransModeler.


Kiterjesztett funkcionális útosztályozási rendszer fejlesztése a geometriai tervezés nagyobb rugalmasságáért

Developing an Expanded Functional Classification System for More Flexibility in Geometric Design

Szerzők: N. Stamatiadis, M. King, R. Chellman, A. Kirk, D. Hartman, J. Jasper, S. Wright (University of Kentucky, Nelson\Nygaard, TND Engineering, University of Kentucky USA)

Terjedelem: 230 oldal

Kivonat:

The modern Functional Classification System (FCS) was developed in the 1970s as a basis for communication between designers and planners. It sought to establish a common framework for classifying roadways based on mobility and access. Since its inception, the application of the FCS has expanded, and is now used throughout the entire project development process and influences all transportation project development phases, from programming and planning through design and into maintenance and operation decisions. However, the focus of the FCS is narrow; as it balances only mobility and access. The limited contextual definitions (urban and rural), do not provide the dynamic range of design elements and guidance needed to balance other competing project needs. The objective of this research is to develop a flexible framework that replaces the FCS and facilitates optimal geometric design solutions that take into account context, functions, and user needs. To develop this alternative classification system, a two-phased approach was employed. The first phase involved a literature review, a survey of transportation agencies/practitioners, identification of existing alternative systems, and an evaluation of those existing alternative systems and their components. Work during this phase identified promising elements to be considered for inclusion in the proposed system. In the second phase, the proposed alternative is fully developed, its implications for design are documented, and the effects on other areas are highlighted. The research team produced a new alternative classification system to aid designers in developing contextual designs that balance a range of user’s needs.


Kiterjesztett funkcionális útosztályozási rendszer utak és utcák számára

An Expanded Functional Classification System for Highways and Streets

Szerzők: N. Stamatiadis, A. Kirk, D. Hartman, J. Jasper, S. Wright, M. King, R. Chellman ( University of Kentucky, Nelson\Nygaard, TND Engineering, USA )

Terjedelem: 84 oldal

Kivonat:

This guidance has been developed to demonstrate the application of the Expanded Functional Classification System (Expanded FCS) for highways and streets. The Expanded FCS provides a flexible framework, which can replace the existing functional classification scheme, in order to facilitate optimal geometric design solutions that take into account environmental context, road functions, and user needs. This system builds upon existing efforts of state departments of transportation (DOTs) that have initiated and implemented a new classification system to address contextual multimodal deficiencies of the existing classification system.

Közösségi közlekedési rendszerek első és utolsó mérföldjének értékelése

First and Last Mile Assessment for Transit Systems

Szerzők: C. Liu, R. Porter, M. Zlatkovic, K. Fayyaz, J. Taylor (Mountain-Plains Consortium USA)

Terjedelem: 45 oldal

Kivonat:

The First Mile Last Mile(FMLM) challenge garners significant attention as a means to assess the accessibility of the first leg to transit and the last leg from public transit. As a critical barrier to public transit accessibility, the challenge provides many opportunities to closely analyze conditions from the level of the transit station upwards to the level of the system-wide network. Its usefulness in contributing to the body of knowledge on barriers to transit access provides planners and researchers important information with implications in increasing ridership, transit efficiency, multimodal travel options, and accessible mobility. In this project, we propose a methodological framework for analyzing the FMLM problems by determining varying causes of poor public transit accessibility and identifying areas with immediate needs for improvements. We showcase the analytical framework using a transit network in the state of Utah operated by the Utah Transit Authority. We also conducted analysis on the impacts of reduced automobile use on personal and environmental health. As a companion product, a spreadsheet-based sketch planning tool is developed to estimate health cost savings as a result of mode shifts from private automobiles to active transportation options.

Mobil telefonos helyazonosítási adatok az utazási viselkedés elemzéséhez

Cell Phone Location Data for Travel Behavior Analysis

Szerzők: Cambridge Systematics, Inc., Massachusetts Institute of Technology, USA

Terjedelem: 155 oldal

Kivonat:

The objectives of this research were (a) to evaluate the extent to which cell phone data accurately reflect daily travel and (b) to develop guidelines on how to best use these data to understand and model travel behavior. Given the interest in new sources of locational data, it is critical to evaluate the strengths and weaknesses of this new stream of data and its applicability to the development and application of travel demand models.

Acélhidak élettartamának meghosszabbítása a korrózió megelőzésével

Corrosion Prevention for Extending the Service Life of Steel Bridges

Szerzők: J.P. Ault, J.D. Dolph, (Elzly Technology Corporation USA)

Terjedelem: 87 oldal

Kivonat:

One of the most often cited problems affecting not only the appearance, but more importantly, the structural integrity of steel bridges, is corrosion—an important issue, not only by itself, but as part of the ever-increasing concern over the nation’s aging and deteriorating infrastructure. A synthesis of current practices and existing knowledge on this particular problem seemed timely. Such a synthesis would provide a better understanding of how to help combat the problem and extend the service life of aging and newly designed steel bridges. The primary approaches for gathering information were through a literature review and a survey of transportation agencies.

Integrált közlekedési és terület-felhasználási modellek

Integrated Transportation and Land Use Models

Szerző: R. Moeckel (Technical University of Munich Germany)

Terjedelem: 91 oldal

Kivonat:

As an aid to decision making, the important interaction between land use and transportation is receiving increased attention. Although the relationship between land use and transportation is obvious, modeling the interaction has not been as easily accomplished. However, various integrated transportation and land use models exist that seek to analyze this interaction, and this synthesis identifies methods and levels of integration now being used by select agencies to support decision making with the use of such models. These models differ considerably in their complexity and requirements for data, expertise, and resources. They range from relatively simple sketch-based approaches to complex behavioral urban and areawide models. Models have different appropriate uses, and each differs in the extent to which transportation–land use interactions are captured. The practice affected by these issues was reviewed, and gaps in knowledge and needed research were identified.

Közúti üzemeltetési gépek optimális újra beszerzési ciklusa

Optimal Replacement Cycles of Highway Operations Equipment

Szerző: R. Hamilton (Dye Management Group, Inc. USA)

Terjedelem: 123 oldal

Kivonat:

Optimal Replacement Cycles of Highway Operations Equipment is essentially both a handbook on equipment replacement concepts and an instruction manual for making cost-effective replacement decisions. The research report presents a process for determining replacement needs for highway operations equipment, identifying candidate equipment units for replacement, and preparing an annual equipment replacement program. The products include a guide and an Excel-based replacement optimization tool to support the equipment replacement process and facilitate its implementation. The guide will help fleet managers determine optimal life cycles and implement systematic replacement processes supported by sound data-driven analysis. In this manner, the guide should help fleet managers determine replacement needs and prepare replacement budgets to provide a highway operations program with a high-quality and dependable fleet to support the agency’s mission. The information contained in the research report should be of interest to fleet managers and state maintenance engineers and to others involved in the replacement aspects of equipment fleet assets.



Hozzászólás

Az email címet nem tesszük közzé. A kötelező mezőket * karakterrel jelöltük