scholarly journals STREETSCAPE TERRITORIES AND THE CASE OF ADDIS ABABA

2015 ◽  
Vol 19 (2) ◽  
pp. 12-21
Author(s):  
Kris Scheerlinck
Keyword(s):  
Urban Growth ◽  
High Speed ◽  
Large Scale ◽  
Addis Ababa ◽  
Urban Fabric ◽  
Formal Approach ◽  
Ongoing Research ◽  
Planning And Design ◽  
High Speed Trains ◽  
The Relationship

Urban transformation is directly related to the planning, design and use of a series of urban infrastructures, from streets to highways, from pedestrian, bicycle, bus or train lines and their connecting transport hubs to rivers, canals or harbor facilities. They play an essential role in the transformation of the urban fabric. Recent societal changes, especially in developing countries, demanding higher mobility and urban interaction, influence the used planning and design strategies to transform or extend urbanized areas by planning or renewing these infrastructures. However, its relationship to the surrounding urban fabric, more specifically the collective spaces it constitutes at the level of the streetscape, is not always an initial or integral part of providing these infrastructures. In many cases, the urban fabric is wrapped around or fragmented by these infrastructural projects, causing scale contrasts and struggle to integrate within, generating processes of misappropriation or misuse. Especially in developing contexts, new infrastructures are often planned and built in a fast way, rarely considering the qualities of the existing urban fabric. During the last decades, research on planning and design models related to the building or integrating of urban infrastructures has been developed and tested via specialised disciplinary approaches to produce insights on the relationship urban infrastructures have with the surrounding urban fabric (Secchi, 2013; Hasan, et. al. 2010; Shannon and Smets, 2009; De Maulder, 2008; Hillier, 1996;). However, additional in-depth research is needed to achieve critical insights on the relationship of infrastructures and their direct environments, starting from their constituent streetscapes - considering the level of the street that defines the perception and use by the inhabitants at an intermediate scale. This paper focuses on an ongoing research project in Addis Ababa (Ethiopia), where different visions and models of urban growth are at stake (Figure 1). The recent increase of (foreign) investment in major infrastructures, changes the city's streetscapes drastically. This large scale and formal approach of installing high speed trains, Light Rail Transit's (LRT) or expanded highways and ring roads, to stimulate urban growth, contrasts with the daily routines of the proper citizens that move around by walking or by means of mini buses, both adding to the informal qualities of the city's streetscapes. Within this multi-centred capital, the location of built and planned housing projects, commercial centres, administrative or commercial high rises is studied in relation to the present infrastructural axes and questions models of proximity, accessibility and permeability. Keywords: Streetscapes, High Speed Trains, LRT, Addis Ababa, Infrastructure

A real-time control method-based simulation for high-speed trains on large-scale rail network

2017 ◽  
Vol 28 (10) ◽  
pp. 1750126 ◽  
Author(s):  
Yutong Liu ◽  
Chengxuan Cao ◽  
Yaling Zhou ◽  
Ziyan Feng
Keyword(s):  
Real Time ◽  
Traffic Flow ◽  
High Speed ◽  
Large Scale ◽  
Simulation Method ◽  
Real Time Control ◽  
Rail Network ◽  
Time Control ◽  
High Speed Trains ◽  
Rail Traffic

In this paper, an improved real-time control model based on the discrete-time method is constructed to control and simulate the movement of high-speed trains on large-scale rail network. The constraints of acceleration and deceleration are introduced in this model, and a more reasonable definition of the minimal headway is also presented. Considering the complicated rail traffic environment in practice, we propose a set of sound operational strategies to excellently control traffic flow on rail network under various conditions. Several simulation experiments with different parameter combinations are conducted to verify the effectiveness of the control simulation method. The experimental results are similar to realistic environment and some characteristics of rail traffic flow are also investigated, especially the impact of stochastic disturbances and the minimal headway on the rail traffic flow on large-scale rail network, which can better assist dispatchers in analysis and decision-making. Meanwhile, experimental results also demonstrate that the proposed control simulation method can be in real-time control of traffic flow for high-speed trains not only on the simple rail line, but also on the complicated large-scale network such as China’s high-speed rail network and serve as a tool of simulating the traffic flow on large-scale rail network to study the characteristics of rail traffic flow.

scholarly journals Monitoring and Modeling Railway Structures on High-Speed Lines with Asphalt Concrete Underlay: A Study on the Bretagne–Pays de la Loire Line

2020 ◽  
Vol 2674 (12) ◽  
pp. 600-607
Author(s):  
Diana Khairallah ◽  
Olivier Chupin ◽  
Juliette Blanc ◽  
Pierre Hornych ◽  
Jean-Michel Piau ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
High Speed ◽  
Large Scale ◽  
Strain Gages ◽  
Railway Transportation ◽  
Dynamic Stresses ◽  
High Speed Railway ◽  
High Frequencies ◽  
High Acceleration ◽  
High Speed Trains

The design and durability of high-speed railway lines is a major challenge in the field of railway transportation. In France, 40 years of feedback on the field behavior of ballasted tracks led to improvements in the design rules. However, the settlement and wear of ballast, caused by dynamic stresses at high frequencies, remains a major problem on high-speed tracks leading to high maintenance costs. Studies have shown that this settlement is linked to the high acceleration produced in the ballast layer by high-speed trains traveling on the track, disrupting the granular assembly. The “Bretagne–Pays de la Loire” high-speed line (BPL HSL), with its varied subgrade conditions, represents the first large-scale application of asphalt concrete (GB) as the ballast sublayer. This line includes 77 km of conventional track with a granular sublayer of unbound granular material (UGM) and 105 km of track with an asphalt concrete sublayer under the ballast. During construction, instruments such as accelerometers, anchored deflection sensors, and strain gages, among others, were installed on four sections of the track. This paper examines the instrumentation as well as the acquisition system installed on the track. The data processing is explained first, followed by a presentation of the ViscoRail software, developed for modeling railway tracks. The bituminous section’s behavior and response is modeled using a multilayer dynamic response model, implemented in the ViscoRail software. A good match between experimental and calculated results is highlighted.

scholarly journals A Concept of Integration of a Vactrain Underground Station with the Solidarity Transport Hub Poland

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5737
Author(s):  
Olena Stryhunivska ◽  
Katarzyna Gdowska ◽  
Rafał Rumin
Keyword(s):  
High Speed ◽  
Low Pressure ◽  
Advanced Technology ◽  
Planning Stage ◽  
Safety Standards ◽  
Planning And Design ◽  
Railway Infrastructure ◽  
Critical Issues ◽  
High Speed Trains ◽  
Underground Station

This paper provides an analysis of a designed underground station infrastructure for vacuum tube high-speed trains for the planned mega transport hub in Poland. The potential of integrating the infrastructure of the station building with sealed low-pressure tubes system is analyzed. The Solidarity Transport Hub Poland is a planned mega hub to be located in Baranów Municipality, Poland, which is comprised of an airport, an airport city, a road, and railway infrastructure. It is to be integrated with the first route of vactrains in Poland. The aim of this paper is to design a hyperloop station building adequate for the advanced technology of low-pressure high-speed trains. Designing a hyperloop station is not trivial, due to technological aspects which have not been hitherto present in airport or railway planning and design, such as low-pressure zones or airlocks which determine possible passenger paths and evacuation roads. Both the mega airport and Polish hyperloop are in the planning stage, therefore, in this paper, available models and designs of the hyperloop station building and infrastructure are used in order to formulate recommendations for further development and identify critical issues related to the safety and reduction of passenger transit time. The main contribution of this paper is a model of the hyperloop station building which respects the principles of spatial planning and safety standards.

Mapping relationship between dynamic responses of high-speed trains and additional bridge deformations

2020 ◽  
pp. 107754632093689
Author(s):  
Hongye Gou ◽  
Chang Liu ◽  
Hui Hua ◽  
Yi Bao ◽  
Qianhui Pu
Keyword(s):  
High Speed ◽  
Coupled Model ◽  
Dynamic Responses ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Running Safety ◽  
High Speed Trains ◽  
Track Bridge ◽  
The Relationship ◽  
Track Deformation

Deformations of high-speed railways accumulate over time and affect the geometry of the track, thus affecting the running safety of trains. This article proposes a new method to map the relationship between dynamic responses of high-speed trains and additional bridge deformations. A train–track–bridge coupled model is established to determine relationship between the dynamic responses (e.g. accelerations and wheel–rail forces) of the high-speed trains and the track deformations caused by bridge pier settlement, girder end rotation, and girder camber. The dynamic responses are correlated with the track deformation. The mapping relationship between bridge deformations and running safety of trains is determined. To satisfy the requirements of safety and riding comfort, the suggested upper thresholds of pier settlement, girder end rotation, and girder camber are 22.6 mm, 0.92‰ rad, and 17.2 mm, respectively. This study provides a method that is convenient for engineers in evaluation and maintenance of high-speed railway bridges.

scholarly journals Active Control of Contact Force for a Pantograph-Catenary System

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Jiqiang Wang
Keyword(s):  
Active Control ◽  
Contact Force ◽  
High Speed ◽  
Large Scale ◽  
Vibration Suppression ◽  
Numerical Study ◽  
Primary Objective ◽  
Geometric Framework ◽  
High Speed Trains ◽  
Catenary System

The performance of the high speed trains depends critically on the quality of the contact in the pantograph-catenary interaction. Maintaining a constant contact force needs taking special measures and one of the methods is to utilize active control to optimize the contact force. A number of active control methods have been proposed in the past decade. However, the primary objective of these methods has been to reduce the variation of the contact force in the pantograph-catenary system, ignoring the effects of locomotive vibrations on pantograph-catenary dynamics. Motivated by the problems in active control of vibration in large scale structures, the author has developed a geometric framework specifically targeting the remote vibration suppression problem based only on local control action. It is the intention of the paper to demonstrate its potential in the active control of the pantograph-catenary interaction, aiming to minimize the variation of the contact force while simultaneously suppressing the vibration disturbance from the train. A numerical study is provided through the application to a simplified pantograph-catenary model.

La grande dimensione: misura e dismisura

TERRITORIO ◽  
2009 ◽  
pp. 9-13
Author(s):  
Remo Dorigati
Keyword(s):  
Urban Sprawl ◽  
Architectural Design ◽  
Large Scale ◽  
Public Buildings ◽  
Urban Fabric ◽  
Large Size ◽  
Planning Strategies ◽  
The Relationship

- The "mega structure" just refers to itself and its dimensions are simply related to the relationship between economical and technological issues, while its vitality is supported by mobility flows. The large scale, both on the physical and on the conceptual side, asks to reflect about the traditional paradigms of urban and architectural design, but most of all about the new relationship occurring between planning strategies and architecture. Large size buildings are mainly located in the urban sprawl areas, with efficient infrastructures and weak urban fabric, where integration is quite difficult. Mega structures have always existed - monuments, public buildings or infrastructures - as every culture has raised its own monuments as a demonstration of power through an impressive possibility of dominion on nature, a continuous challenge of man.

scholarly journals Design of large-scale streamlined head cars of high-speed trains and aerodynamic drag calculation

2017 ◽  
Vol 44 (4) ◽  
pp. 89-97 ◽  
Author(s):  
Zhenfeng Wu ◽  
Enyu Yang ◽  
Wangcai Ding
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Production Control ◽  
Aerodynamic Drag ◽  
Design Method ◽  
Control Point ◽  
Surface Characteristics ◽  
High Speed Train ◽  
Research Subjects ◽  
High Speed Trains

Aerodynamic drag plays an important role in high-speed trains, and how to reduce the aerodynamic drag is one of the most important research subjects related to modern railway systems. This paper investigates a design method for large-scale streamlined head cars of high-speed trains by adopting NURBS theory according to the outer surface characteristics of trains. This method first created the main control lines of the driver cab by inputting control point coordinates; then, auxiliary control lines were added to the main ones. Finally, the reticular region formed by the main control lines and auxiliary ones were filled. The head car was assembled with the driver cab and sightseeing car in a virtual environment. The numerical simulation of train flow field was completed through definition of geometric models, boundary conditions, and space discretization. The calculation results show that the aerodynamic drag of the high-speed train with large-scale streamlined head car decreases by approximately 49.3% within the 50-300 km/h speed range compared with that of the quasi-streamlined high-speed train. This study reveals that the high-speed train with large-scale streamlined head car could achieve the purpose of reducing running aerodynamic drag and saving energy, and aims to provide technical support for the subsequent process design and production control of high-speed train head cars.

scholarly journals Environmental Design Features for Large-Scale Nature-Based Solutions: Development of a Framework That Incorporates Landscape Dynamics into the Design of Nature-Based Solutions

2021 ◽  
Vol 13 (11) ◽  
pp. 6123
Author(s):  
Bo-Syuan Wu ◽  
Laddaporn Ruangpan ◽  
Arlex Sanchez ◽  
Marzenna Rasmussen ◽  
Eldon R. Rene ◽  
...  
Keyword(s):  
Continuous Monitoring ◽  
Large Scale ◽  
Environmental Design ◽  
Landscape Dynamics ◽  
Evidence Based ◽  
Planning And Design ◽  
Case Study Site ◽  
The Relationship ◽  
The Eu

Large-scale nature-based solutions (NBS) contribute to the change in large-scale landscapes and ecosystems for which continuous monitoring activities would be necessary to reflect the constantly changing environment. To fill the gap in the design-making process of implementing NBS, a framework that incorporates the landscape dynamics into the design of NBS is expedient and beneficial. This research addresses the above gap and presents a practically applicable framework for large-scale NBS that incorporates landscape dynamics into the design of NBS. To amplify the power of stakeholders’ involvement and evidence-based knowledge (i.e., field experiences and literature reports), the framework developed in this study was evaluated on a case-study site in Odense area, Denmark, within the EU-funded RECONECT project. Furthermore, this study also addresses the relationship between landscape dynamics and biodiversity by performing a detailed literature review. The results obtained from this work demonstrate that the framework developed can be applied to existing large-scale NBS and it has the potential to recommend guidelines during the planning and design step of large-scale NBS.

scholarly journals The Cycles of Impermanent Alterity in Nazaré

2018 ◽  
pp. 434-465
Author(s):  
Cidália Ferreira Silva ◽  
Marisa Carvalho Fernandes
Keyword(s):  
Everyday Life ◽  
Large Scale ◽  
The Other ◽  
Small City ◽  
Economic Activities ◽  
Urban Fabric ◽  
The Relationship ◽  
Lived Time

What happens when a small city expands from 15,000 to 100,000 inhabitants in the summertime? How do temporary inhabitants of Nazaré (Portugal) change the rhythms of its everyday life? How does large-scale tourism change their supporting economic activities or even replace activities such as fishing? Is this seemingly rigid urban fabric elastic enough to expand and adapt to these exponential “others”? The “impermanent alterity” explains the result of the relationship established between land and water, between the “I” and the “other” that come to Nazaré to step onto the warm sand during the summer days. There is a visible cycle of summer-winter change, which the network of lived time interconnections can be found in simple things like the gray pavement line organizing uses, as a device that adapts matter to the cycles of change. Time is the operator of this “impermanent alterity,” and the residents and outsiders alike make it visible.

scholarly journals Analysis methods of the dynamic structural stress in a full-scale welded carbody for high-speed trains

2018 ◽  
Vol 10 (10) ◽  
pp. 168781401880591 ◽  
Author(s):  
Yaohui Lu ◽  
Heyan Zheng ◽  
Chuan Lu ◽  
Tianli Chen ◽  
Jing Zeng ◽  
...  
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Large Scale ◽  
Dynamic Stress ◽  
Full Scale ◽  
Structural Stress ◽  
Random Load ◽  
Analysis Methods ◽  
Welded Structure ◽  
High Speed Trains

The calculation of the dynamic stress of a large and complex welded carbody is the key to the fatigue design and the durability evaluation of the carbody. Adopting the advanced structural stress based on the finite element method, a new finite element transformation method between random loads and dynamic stresses is proposed to be applied in carbody for high-speed trains. The multi-axial random dynamic load spectrums of full-scale carbody are obtained by the vehicle system dynamics method, and the shell finite element model of a full-scale carbody is established. Adopting the concept of a surrogate model, the finite element transformation relationship between the random load and the dynamic structural stress at concerned points is constructed by using multidisciplinary methods to compute the dynamic stress spectrums of concerned points at the welding seam, and dynamic structural stresses are compared and validated through carbody rig-test. The analysis methods of dynamic structural stress are performed systematically for a full-scale welded structure, which provides reference methods for the fatigue durability evaluation of large-scale welded structures.

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