scholarly journals S-Shaped Transition Curves as an Element of Reverse Curves in Road Design

2019 ◽  
Vol 14 (4) ◽  
pp. 484-503 ◽  
Author(s):  
Andrzej Kobryń ◽  
Piotr Stachera
Keyword(s):  
Research Topic ◽  
Vertical Alignment ◽  
Geometric Properties ◽  
Road Design ◽  
Geometric Systems ◽  
Practical Usefulness ◽  
Circular Curves ◽  
Traditional Approaches ◽  
Transition Curves

A road designing involves horizontal and vertical alignment. The horizontal geometry is formed by straight and curvilinear sections that are traditionally formed using circular and transition curves (mainly the clothoid). Different geometric systems that are designed using circular and transition curves are between others circular curves with symmetrical or unsymmetrical clothoids, combined curves, oval curves and reverse curves. Designing these systems is quite complex. Therefore, so-called S-shaped transition curves are an alternative to traditional approaches. These curves are known from literature and are modern geometric tools for the shaping of reverse curves. The paper analyses the basic geometric properties of these curves as well as compare to the geometry of the appropriate geometric systems, which are formed with clothoid or using S-shaped transition curves. In addition, a procedure for designing reverse curves using S-shaped transition curves was proposed. Another research topic was the comparison of the analysed reverse curves (created using polynomial transition curves) with traditional curves (created using the clothoid). The results of the studies, despite the noticeable differences in the geometry of the compared components, confirm the practical usefulness of the S-shaped transition curves for designing the geometry of the route.

scholarly journals Railway Transition Curves: A Review of the State-of-the-Art and Future Research

2020 ◽  
Vol 5 (5) ◽  
pp. 43 ◽  
Author(s):  
Tanita Fossli Brustad ◽  
Rune Dalmo
Keyword(s):  
Vehicle Dynamics ◽  
State Of The Art ◽  
Evaluation Criteria ◽  
Research Topic ◽  
Point Of View ◽  
Future Research ◽  
Geometric Continuity ◽  
Railway Industry ◽  
Literature Reviews ◽  
Transition Curves

Transition curves are a useful tool for lateral alignment of railway segments. Their design is important to ensure safe and comfortable travel for passengers and cargo. Well designed transition curves can lead to reduced wear of tracks and vehicles, which is beneficial from a maintenance point of view. Extensive studies have been performed through decades to find transition curves that can replace existing railway segments for the purpose of enhancing certain properties. Those studies seek to form curves that satisfy desired evaluation criteria, which are often connected to geometric continuity between the curve segments, and vehicle dynamics, to secure a smooth ride. This research topic is still ongoing and active at present. Recent results and findings are in line with the developments on the topic of vehicle dynamics and within the railway industry. For this reason it is appropriate to collect and discuss the latest work, since there are no up-to-date detailed literature reviews available. This paper explores the present state-of-the-art of railway transition curves, and identifies some of the research challenges and future research opportunities in the field.

scholarly journals Does the shape of the road influences wildlife roadkills? Evidence from a highway in Central Andes of Colombia

2020 ◽  
Vol 6 (1) ◽  
pp. 58-70
Author(s):  
Julián Arango Lozano ◽  
Dahian Patiño-Siro
Keyword(s):  
Central Andes ◽  
Traffic Density ◽  
Highway Infrastructure ◽  
The Road ◽  
Road Design ◽  
On The Road ◽  
Conservation Plans ◽  
Straight Lines ◽  
Transition Curves ◽  
Wildlife Mortality

Highway infrastructure is a source of multiple environmental problems, where wildlife roadkills is the most noticeable impact. Most of research in roadkills have focused in how different aspects as seasons, traffic density, location of roads, among others, have implications in the wildlife mortality on roads. However, little research have been developed on understanding how geometrical road design affects wildlife mortality. On a highway in the central Andes of Colombia, we tested whether the geometric design, it is horizontal alignment and vertical curves influence the mortality of vertebrate animals on the road. We determined the number of straight lines, circular, transition curves and vertical convex curves along the entire route of the highway (13.9 km), and between April 2018 and December 2019 we made 4 weekly tours in search of wildlife roadkills. With records, we related and compared groups of animal deaths and road shapes. We got 95 roadkills where reptile’s deaths were more than the 47% of total. We found no dependence in the distribution of deaths by Class of animals on the road shapes; the shape in which most deaths occurred was straight line (58 deaths). However, when the mortality rate per meter of route was obtained on the shape units, we found that the circular and transition curves presented two and three times (respectively) higher mortality rates than straight lines. Curved sections are presented as more dangerous geometric designs than straight lines for wildlife, regardless of their length on the road. Our research provides information necessary to take into account the relationship of geometric road design in the development of management and conservation plans of altered ecosystems with road infrastructure.

scholarly journals Horizontal Alignment Security Design Theory and Application of Superhighways

2020 ◽  
Vol 12 (6) ◽  
pp. 2222 ◽  
Author(s):  
Yu-Long Pei ◽  
Yong-Ming He ◽  
Bin Ran ◽  
Jia Kang ◽  
Yu-Ting Song
Keyword(s):  
Design Theory ◽  
Construction Technology ◽  
Security Design ◽  
Operating Characteristics ◽  
Highway Design ◽  
Vehicle Performance ◽  
Horizontal Alignment ◽  
Road Design ◽  
Design Speed ◽  
Circular Curves

In China, the maximum design speed of highways is 120 km/h, which first appeared in the Highway Engineering Technical Standard (Trial) in 1951. However, vehicle performance, road design, and construction technology have been greatly improved over the past 68 years. To adapt to the development demands of highway design speeds above 120 km/h in the future, it is urgent to study superhighway alignment design theory. Therefore, the horizontal alignment security design theory of superhighways was developed in this paper. First, the definition, classification, and construction mode of a superhighway and suitable vehicles of different grades are presented. Then, the lengths of straight lines were limited to reduce driving fatigue. Next, the minimum radii of circular curves were calculated based on driver characteristics and stress analysis of operating vehicles. Finally, the minimum lengths of transition curves were calculated based on the centrifugal acceleration of the operating vehicles, the travel time, and the passenger visual characteristics. The calculation and analysis results show that the superhighway linear features conform to the vehicle operating characteristics, and can ensure the safety of driving.

Transnational Human Rights Networks

2009 ◽  
Vol 7 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Min Tang
Keyword(s):  
Human Rights ◽  
Critical Analysis ◽  
Research Topic ◽  
International Studies ◽  
International Human Rights ◽  
Future Studies ◽  
Research Scholarship ◽  
International Human ◽  
Human Rights Norms ◽  
Traditional Approaches

‘Transnational human rights networks' has become a hot research topic for international human rights studies in recent years. It mainly documents and theorizes the transnationalization or internationalization of human rights norms and practices during the last several decades. It began as a distinctive field of research scholarship and has grown to challenge the traditional approaches to international studies. This review introduces the major tenets of this field and, without downplaying their contribution to international studies, it also tries to point out several problems in the conceptualization, theorization and methodology of the current studies on human rights networks. This critical analysis is followed by some suggestions for future studies.

scholarly journals Improvement of Characteristics of the Railway Direction Kharkiv-Dnipro with the Purpose of Introducing the high-speed Passenger Traffic

2019 ◽  
Vol 67 ◽  
pp. 02004
Author(s):  
Maksym Kutsenko ◽  
Sergii Zmii ◽  
Oleksandr Rozsokha ◽  
Ganna Shapoval ◽  
Olga Semenova
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Rail Transport ◽  
Small Radius ◽  
High Speed Rail ◽  
Passenger Traffic ◽  
High Speed Trains ◽  
Service Sectors ◽  
Circular Curves ◽  
Transition Curves

The high efficiency of high-speed rail transport contributes to its development both in the service sectors and in the construction of devices for servicing high-speed trains, in particular, track development. At the same time, it is necessary to take into account the obvious problems that accompany the process of reconstruction of railways during the transition to high-speed passenger traffic. Among them, the presence of small radii of circular curves, an insufficient length of straight inserts and transition curves should be noted. In this paper, it is proposed to consider small-radius curves located close to each other as one common module when reconstructing railways with the aim of introducing high-speed passenger traffic. The implementation of this approach will allow solving one of the main problems - straightening of the railway section. This will increase the speed of passenger trains and reduce travel time by reducing the length of the route. The article deals with the task of reconstruction of modules consisting of three adjacent curves, which occur when improving the characteristics of the plan of the Kharkiv-Dnipro railway direction.

scholarly journals Transition curves in vertical alignment as a method for reducing fuel consumption

2014 ◽  
Vol 9 (4) ◽  
pp. 260-268 ◽  
Author(s):  
Andrzej Kobryń
Keyword(s):  
Fuel Consumption ◽  
Comparative Studies ◽  
Vertical Alignment ◽  
New Approach ◽  
Numerical Studies ◽  
Fuel Consumption Reduction ◽  
Consumption Reduction ◽  
Straight Lines ◽  
Transition Curves ◽  
Methods Numerical

This paper presents a new approach to the fuel consumption reduction. This approach is based on vertical curve designs based on transition curves. The work presents selected curves, which are used for this purpose. Moreover, the results of comparative studies are shown for these curves, carried out in order to compare the possible reduction of fuel consumption in vertical curves designed using both conventional and proposed methods. Numerical studies were based on German engineering guidelines. In the case of vertical arcs formed by transition curves, fuel consumption indexes prove to be significantly lower than in curves based on a grade line consisting of straight lines with parabolic arcs. The obtained results indicate the advisability of forming vertical curves using transition curves.

scholarly journals Employing Polyethnography to Navigate Researcher Positionality on Weight Bias

2017 ◽  
Author(s):  
Nancy Arthur ◽  
Darren Lund ◽  
Shelly Russell-Mayhew ◽  
Sarah Nutter ◽  
Emily Williams ◽  
...  
Keyword(s):  
Social Justice ◽  
Research Agenda ◽  
Life Experiences ◽  
Interdisciplinary Team ◽  
Weight Bias ◽  
Research Topic ◽  
Research Approach ◽  
Professional Literature ◽  
Common Life ◽  
Traditional Approaches

Researchers often focus on the content of their research interests but, depending on the research approach, may pay less attention to the process of locating themselves in relation to the research topic. This paper outlines the dialogue between an interdisciplinary team of researchers who were at the initial stages of forming a research agenda related to weight bias and social justice. Using a polyethnographic approach to guide our discussion, we sought to explore the diverse and common life experiences that influenced our professional interests for pursuing research on weight bias. As a dialogic method, polyethnography is ideally suited for the reflexive work required of researchers seeking to address issues of equity and social justice. Beyond more traditional approaches such as journaling, personal interviews, or researcher notes, the intersubjectivity highlighted by this method affords a richer space for exploration, challenging ideas, taking risks, and collectively interrogating both self and society. Following a discussion of positionality, the dialogue between researchers is presented, followed by their critique of the discussion, informed by professional literature.

Sign in / Sign up

Export Citation Format

Share Document