A közlekedésépítési szakterület mérnöki és tudományos folyóirata. ISSN 2064-0919
10. szám
2017. ősz
10
Bejegyzés

Nemzetközi szemle: Március

A közúti közösségi közlekedés előnyben részesítése

Prioritising On-Road Public Transport
Szerző(k):
A. Lee, G. McCabe
Austroads Australia
Terjedelem: 68 oldal

On-road public transport provides the ability for people to move between their homes, employment, recreation and services efficiently with less road space being required per passenger than private car use. In response to this, practitioners in many Australian and New Zealand cities are putting in place road space and signalling techniques and technologies which can improve the travel time, travel time reliability, frequency and comfort for on-road public transport users. This report provides a best practice evaluation of priority measures for the provision of road-based facilities for buses and light rail systems (including streetcars and trams) for application in Australia and New Zealand. It highlights case studies across jurisdictions which show a range of impacts from prioritising on-road public transport.

 

Szálerősített polimerek alkalmazása a közúti infrastruktúrában

Use of Fiber-Reinforced Polymers in Highway Infrastructure
Szerző(k):
Y.J. Kim
University of Colorado Denver USA
Terjedelem: 169 oldal

This synthesis presents the use of fiber-reinforced polymer (FRP) composites in highway infrastructure. The state-of-the-art review of FRP applications includes material types and characteristics, application guidelines, FRP-reinforced concrete, FRP-prestressed concrete, FRP-strengthened concrete, FRP stayin-place members and FRP decks, and life-cycle cost analysis. FRP composites consisting of fibers and a polymeric resin provide enhanced engineering properties and performance compared with conventional construction materials; for example, favorable strength-to-density ratio, non-corrosiveness, and reduced maintenance costs. Three types of FRP materials are employed in practice: carbon FRP (CFRP), glass FRP (GFRP), and aramid FRP (AFRP). Basalt FRP (BFRP) is an emerging material. Typical resins used to form FRP composites are epoxy, polyester, and vinylester. To assist practitioners who are interested in FRP applications, several standards organizations or professional societies publish design guidelines, codes, and specifications.

 

Út pályaszerkezet mechanikai-empirikus tervezése – a helyi kalibráció, az alapozás, valamint a tervezési és megbízhatósági határértékek hatása

Pavement ME Design – Impact of Local Calibration, Foundation Support, and Design and Reliability Thresholds
Szerző(k):
N. Tran, M.M. Robbins, C. Rodezno, D.H. Timm
National Center for Asphalt Technology, USA
Terjedelem: 53 oldal

The Mechanistic-Empirical Pavement Design Guide (MEPDG) and the accompanying AASHTOWare Pavement ME Design software (hereafter referred to as the ME Design software) have been developed to replace the empirical AASHTO Pavement Design Guides. The MEPDG represents a quantum leap forward from the empirical pavement design procedures. As indicated in a survey of state agencies conducted in 2013, 43 agencies were evaluating the MEPDG, and 15 agencies planned to implement the new design procedure in the next two years. The implementation plans of these agencies include, among other elements, important steps for conducting local calibration to account for differences in state practices, policies, and local conditions, and selecting design thresholds and reliability levels for acceptable pavement designs. Without properly conducting these important implementation steps, the adoption of the MEPDG will not make the pavement design process “better.” In fact, it has been suggested that use of the globally calibrated ME Design software may potentially yield inaccurate asphalt pavement designs. Recognizing the importance of local calibration and selection of design thresholds and reliability levels, this study provides information and evidence to support the need for local calibration of the MEPDG and careful consideration of design thresholds and reliability levels in the implementation process. The results of this research effort are presented in two reports. This (second) report presents results of a case study that compares pavement designs conducted with global and local calibration coefficients to illustrate the importance of conducting local calibration of the
MEPDG in the implementation process. In addition, it provides results of sensitivity analyses that show the effect of performance criteria, reliability levels, and foundation support on pavement design.
 

Önvezető és összekapcsolt járművek hatása a gyalogosokra és kerékpárosokra

Automated and Connected Vehicles, Pedestrians, and Bicyclists
Szerző(k):
L. Sandt, J.M. Owens,
Pedestrian and Bicycle Information Center, USA
Terjedelem: 26 oldal

Pedestrians and bicyclists are a powerful indicator of the social and economic health and safety of a community. A high level of pedestrian and bicycle activity in a community is often associated with more robust economies and healthier, more socially-cohesive populations, while a lack of pedestrian and bicycle activity on roadways can be an indicator that personal security and safety needs are not being met or that destinations cannot be accessed on foot or by bike. Presently, technology innovations are disrupting the status quo and reshaping the ways in which people travel. Auto manufacturers are offering new vehicle automation technologies in an effort to improve safety, ease the driving task, and appeal to car buyers. At the same time, nontraditional entities—such as technology firms like Google, Uber, and nuTonomy—are adopting new roles in the transportation arena, advancing shared mobility services and hastening the speed of automation technology development. As vehicle technologies become more automated, navigation around and interactions with pedestrians and bicyclists in complex travel environments will determine their success. Public uptake of automated vehicles on a large scale basis will not happen until pedestrian and bicycle safety issues are addressed. Despite this fact, pedestrian and bicyclist safety and health issues are not at the forefront of automated vehicle discussions and research. For example, a January 2017 content analysis of 432 United States and international articles related to automated vehicle issues identified fewer than 20 that discussed pedestrian or bicycle topics, either briefly or in depth. This paper presents ten key challenge areas that need to be at the center of automated vehicle.

 

Az infrastruktúra vagyon teljesítményének mérése és a használói megelégedettség mérése: a működő rendszerek áttekintése

Measuring infrastructure asset performance and customer satisfaction: a review of existing frameworks
Szerző(k):
J. Wilson, D. Mitchell
Bureau of Infrastructure, Transport and Regional Economics, Department of Infrastructure and Regional Development, Canberra, Australia
Terjedelem: 170 oldal

Over the past several decades, Australia has corporatized or privatised many of its major infrastructure assets—including telecommunications networks, electricity assets, airports, railways and major ports—and relied increasingly on the private sector for procurement of new infrastructure. Private sector involvement in infrastructure has delivered considerable economic benefits, through improved productivity, reduced costs to consumers and delivery of projects at a lower cost. However, many infrastructure markets are characterised by high fixed (sunk) costs and low marginal costs, and hence naturally disposed to one or few suppliers, which can lead to less efficient market outcomes. While not a direct substitute for competition or appropriate regulation, customer performance measures can be used to provide a form of accountability for infrastructure operators’ performance, especially where competition is limited. This report presents a consistent and general framework for comparing performance across different infrastructure asset types, combining objective performance measures with customer satisfaction survey results, across various infrastructure performance aspects—reliability, amenity, price, safety, availability and timeliness. The framework can be applied across infrastructure asset types, and allows customers to easily identify which operators are performing well, and in which areas. The infrastructure performance and customer satisfaction framework is a first step towards presenting clearer information on infrastructure performance to customers, and may be a way to prompt infrastructure operators, governments and policy makers to think more critically about the needs and priorities of the users of Australia’s infrastructure.

 

Folytonos behajlásmérő eszközök értékelése Louisiana államban – gördülő kerekes behajlásmérő

Assessment of Continuous Deflection Measurement Devices in Louisiana – Rolling Wheel Deflectometer
Szerző(k):
M.A. Elseifi, O. Elbagalati
Louisiana State University USA
Terjedelem: 151 oldal

The use of the Rolling Wheel Deflectometer (RWD), which measures deflections at highway speeds, offers the potential to characterize the structural capacity of pavements without delays and in a cost effective way. The objective of this study was twofold. First, this project evaluated pre-developed structural capacity indicators in predicting pavement structural deficiency based on RWD measurements. Based on this evaluation, the research team introduced modifications to improve prediction of pavement structural capacity. Second, a methodology was developed to integrate the most promising structural capacity indicator into the Louisiana Pavement Management System (PMS) decision matrix and the State overlay design procedure. Furthermore, this project assessed the cost efficiency of RWD testing in identifying and repairing structurally-deficient sections prior to reaching very poor conditions, which may require complete reconstruction. Among the pre-developed structural capacity indicators, the SNRWD was found to be the most promising model. Modifications were introduced to the SNRWD model to improve its efficiency in identifying structurally-deficient pavements and to allow for predicting the Structural Number (SN) at a 0.1-mile interval. A model was developed to estimate the subgrade resilient modulus (Mr) based on the RWD data. To facilitate implementation of the results, a framework was developed to incorporate RWD testing results in Louisiana PMS and the State overlay design procedure. Results of the study found that RWD can result in significant savings to the Department if implemented in testing medium to high traffic volume roads with an Annual Average Daily Traffic (AADT) of 5,000 or more.

 

Különlegesen nagy teljesítményű beton hídburkolat helyszíni tesztelése

Field Testing of an Ultra-High Performance Concrete Overlay
Szerző(k):
Z.B. Haber, J.F. Munoz, B.A. Graybeal
Office of Infrastructure Research & Development, Federal Highway Administration USA
Terjedelem: 60 oldal

Bridge decks are commonly rehabilitated using overlays depending on the cause of deck deterioration, available budget, and desired service life of the rehabilitated structure. One emerging solution for bridge deck rehabilitation is thin, bonded ultra-high performance concrete (UHPC) overlays. As an overlay material, UHPC can provide both structural strengthening and protection from ingress of contaminates using a 1-in (25 mm) to 2-in (51 mm) layer of material. The first U.S. deployment of UHPC as a bridge deck overlay was completed in May 2016 on a reinforced concrete slab bridge located in Brandon. A few months after installing the UHPC overlay, a field inspection of the bridge identified some locations along the deck where delamination may have occurred. To address this concern, a field study was conducted in November 2016 to evaluate the bond between the UHPC overlay and the substrate concrete bridge deck. Researchers from the Federal Highway Administration’s (FHWA) Turner-Fairbank Highway Research Center (TFHRC) synthesized photographic evidence, conducted a field inspection of the bridge deck surface using a chain drag, and conducted physical testing of the UHPC-concrete interface bond using the direct tension bond pull-off test. Tested samples were taken back to TFHRC and the UHPC-concrete interface subsequently analyzed using scanning electron microscopy (SEM). The pull-off test data indicated that the UHPC overlay and the existing concrete bridge deck was intact, which was confirmed by SEM analysis.
 

Az együttműködő intelligens közlekedési rendszerek és az önvezető járművek biztonsági előnyei Ausztráliában és Új-Zélandon

Safety Benefits of Cooperative ITS and Automated Driving in Australia and New Zealand
Szerző(k):
S. Ballingall, C. Jones, J. Wall
Austroads Australia
Terjedelem: 59 oldal

Two rapidly developing technology areas, Cooperative Intelligent Transport Systems (C-ITS) and Automated Driving applications, are reputed to have a substantial impact on road trauma through the increased use of technology both to assist drivers with the driving task, as well as providing enhanced crash avoidance capabilities. This project aimed to identify emerging C-ITS and AD applications and assess their potential safety benefits for Australia and New Zealand. A comprehensive literature review and expert consultation found that C-ITS and AD were predicted to have significant potential to reduce road crash risk and injury consequences, with estimates varying widely between studies.
Using an analysis of Australian serious injury real-world crashes, expert estimates were made of the potential effectiveness of the following light passenger vehicle applications, as well as estimates of the annual savings in serious injuries Australia and New Zealand-wide. Despite the clear potential benefits, several limitations were found that will need to be addressed before widespread implementation becomes possible.

 

Állami és mega-regionális utazás előrebecslő modellek: áru- és személyforgalom

Statewide and megaregion travel forecasting models: freight and passenger
Szerző(k):
Rick Donnelly, Rolf Moeckel
Parsons Brinckerhoff, USA, Technical University Munich, Germany
Terjedelem: 121 oldal

Statewide and megaregion travel demand models are used to help formulate plans and policies, evaluate and prioritize projects and programs, and assess the economic and social impacts of major transportation investments. They are used in 39 states today, compared with the 19 states documented as using them in a similar synthesis a decade ago. The broader adoption of these models reflects the need to evaluate policies and investments focused on planning for megaregions, intercity travel and freight planning, and better data for statewide planning. In addition to their wider use they have increasingly adopted advanced modeling techniques pioneered in urban areas, such as microsimulation of synthetic households and firms, activity-based demand models, and dynamic traffic assignments. These approaches are applied to both person and freight travel analyses and are poised to take advantage of emerging data and techniques. The goal of this synthesis is to document current practices and emerging trends in statewide and megaregion travel forecasting. Several specific questions were posed to focus the investigation into issues such as the motivation for and capabilities of statewide and megaregion models, options for extending them and challenges states face doing so, data requirements, how they are used and integrated with other models, institutional constraints, and emerging trends and methods. Several related issues were investigated as well, including performance monitoring, alternative forecasting approaches, and how states are addressing hot topics such as pricing and congestion, multi-state corridors, and new transportation modes.

 

Könnyű ejtősúlyos behajlásmérővel végzett modulus mérések szabványosítása a tömörítés minőségének biztosítására

Standardizing Lightweight Deflectometer Modulus Measurements for Compaction Quality Assurance
Szerző(k):
C. Schwartz, Z. Afsharikia, S. Khosravifar

Terjedelem: 147 oldal

To evaluate the compaction of unbound geomaterials under unsaturated conditions and replace the conventional methods with a practical modulus-based specification using LWD, this study examined three different LWDs, the Zorn ZFG 3000 LWD, Dynatest 3031 LWD, and Olson’s LWD-1. These devices were selected to represent the range of commercially available testing configurations. Following the selection, a unique large-scale controlled experimental setting was designed and constructed for preliminary investigations. In addition to evaluation of the LWDs, two non-nuclear water content measurement techniques, namely a volumetric water content sensor and a gravimetric moisture analyzer, were assessed. Additional material was collected for further routine and advanced tests in the laboratory, including compaction moisture-density relations and resilient modulus tests on samples prepared at optimum and field conditions. Lastly, the concept of LWD testing directly on the compacted Proctor mold was developed to derive the target modulus values for the field.

 


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