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Simultaneous Influence of the Track Axis Curvature and the Support Line Obliquity at Railway Bridge Superstructures with Steel Beams Embedded in Concrete

Abstract

For new railway bridges with small spans (L ≤ 35.00 m) superstructures with steel beams embedded in concrete are recommended and used, which can ensure the requirements of strength and especially stiffness, regardless of velocity.

In all the design prescriptions used so far for superstructures with steel beams embedded in concrete, and even in the technical literature, there is little information and data on the influence of the support line obliquity and the track axis curvature in the design and calculation of these types of structures.

In the design code, if certain conditions related to the geometry of the superstructure are met (obliquity, curvature) the calculation is a simplified one, made on a single isolated longitudinal beam of the deck; otherwise, if the conditions are not met, finite element program analysis is recommended.

The article aims to study the situations in which the requirements of the design prescriptions are not met.

Open access
Testing the Functionality and Performance of a Rail Damper

Abstract

The rail dampers are mechanical devices which work as dynamic absorbers to reduce the rail vibration and rolling noise. The paper shows the experimental results from the functionality and performance testing of an experimental demonstrative rail damper. The vibration attenuation takes the highest values, namely 6-22 dB, between 160 and 1000 Hz.

Open access
Comparative Study on the Applicability of Analytical and Experimental Methods in the Analysis of the Safe Use of Rail Tankers Carrying Petroleum Products Under Pressure

Abstract

The safety of railways has been and remains a critical topic. Whether it is infrastructure or rolling stock, the issue of safety is a permanent concern of the utmost importance, being reflected in the efficiency of any transport system.

This paper focuses on the safety in operation of pressure vessels that equip railway tanks. There are many articles and works on this subject, and it is well-known that there are both national and international regulations regarding their design, execution, operation and maintenance. Also, there are quite a few reports on the BLEVE (Boiling Liquid Expanding Vapour Explosion) phenomenon resulting in material damage and significant casualties. The BLEVE-type explosion is not considered a chemical explosion derived from a gas-air explosive environment (also present in non-flammable gases), but rather a mechanical explosion through over-pressurization.

Thus, we propose a comparative study between the results obtained using theoretical methods and those obtained as a result of tensoresistive measurements on such a tanker.

Open access
Optimization of the Synergies Between Preparation of High-Speed Railway Train Running Diagram and Station Route Allocation Plan

Abstract

Introduction. Station route allocation plan is an important extension of the train running diagram and the both are closely intertwined so the overall research on the synergetic preparation method is more beneficial in improving the preparation quality of the train running diagram and providing better service for passengers. Therefore, the research topic has practical significance.

Methodology. Based on extensive literatures, this paper studies the synergetic preparation method of train running diagram and station route allocation plan in detail and analyses their association for providing a theoretical basis for the synergetic preparation method.

Results. This work introduces the synergetic, analyses the systematic characteristics of the operation organization system of high speed railway and puts forward the optimization strategy of train running diagram and station route allocation plan.

Conclusions. The work provides the solution for the preparation of the train running diagram and station route allocation plan by solving the examples based on the relevant optimization factors, such as train running in districts and train arrangement.

Open access
Pedestrianism as an Effective Tool for Sustainable Intra-City Commuting in Calabar, Southern Nigeria

Abstract

The promotion of walking has become a global strategy in sustainable urban transportation planning. This is with the aim of reducing the urban commuter’s problems that result from the dominance of motorized urban transit, especially in developing countries with an increasing rate of urbanization. This study is carried out in Calabar, Southern Nigeria with the aim of assessing the conditions under which pedestrianism is enhanced. Research questionnaires were administered to household heads in all 22 localities with political delineation (wards) in the city. Respondents were sampled using the stratified sampling technique where every 10th residential house is sampled after the initial listing of houses. Logistic regression analysis was conducted to predict the conditions under which about 382 household heads (about 98% respondent rate) in Calabar could undertake utilitarian walking using factors such as motorized traffic, weather conditions, lack of safety of pedestrians and socio-economic variables as category predictors. A test of the full model against a constant single model was statistically significant, indicating that the predictors, as a set, reliably distinguished utilitarian walking and non-walking (chi square = 60.544, p < .001 with df = 17). Nagelkerke’s R2 of .232 indicated a moderately strong relationship between prediction and grouping. Prediction success overall was 70.5% (53.5% for non-walking, and 81.5% for walking). The Wald criterion demonstrated that only pedestrian conflict, lack of safety of pedestrian and the age of the pedestrian made a significant contribution to the prediction in model 1 (p = .000). Furthermore, about 99.2% of pedestrians indicated walking distances of not more than 5km while on the other hand, they can afford 0.8km to bus station, 3km to school, 5km for shopping, and about 20km for recreation trips. The study recommended counseling strategies for promoting pedestrianism among which is the development of pedestrian walkways and complementary facilities to enhance pedestrian safety and comfort.

Open access
Rationale of Complex Indicator of Quality of Public Transport

Abstract

The significance of the criteria for assessing the quality of the urban passenger transport is investigated in the article. The results of the processing of field studies have identified factors that can be used for the assessment of the quality of the projects of urban passenger transport. The method of estimation of indicators of quality for the passengers during the trip is given and the values of weighting coefficients of individual quality indicators for the elements of the trip are determined. The method of determining the complex quality indicator during the performance of the trips in the projects of public transport is developed. It is shown that the trip components influence the quality of passenger trips in the following order: waiting time at the stop, time of the pedestrian part of the trip, travel time, dynamic coefficient of capacity utilization.

Open access
Role of CPEC in Development of Trade, Transport and Economy of Pakistan

Abstract

The objectives of the study were to measure the efficiency in trade and transport through China Pakistan Economic Corridor (CPEC) and to ascertain efficiency in trade and economic development through developed transport infrastructures. The present study was conducted in Peshawar, Pakistan. The data was collected from the relevant developing sectors and stakeholders through CPEC including investors of Khyber Pakhtunkhwa Chamber of Commerce and Peshawar Railway Station track employees. Majority of bi-variate analysis through chi-square test result showed that there was a strong and significant association between the project of CPEC and efficiency in trade and transport in terms of economy. Similarly, a strong and significant association was found between the development of transport routes through CPEC and smooth transportation of goods and services. Furthermore, a strong and significant association was found between CPEC project and improvement in travelling potential. Similarly, a significant association was found between development in transport infrastructure and fastness and reliability in business travelling. In the same way, a significant association was found between CPEC and increase in the geographical size of the labour market. As in the chain, a strong and significant association was found between the development of transport infrastructures through CPEC and increase in labour force productivity along with an increase in the range of choice of individual and firms. This could come true that CPEC as a project would ensure smooth efficiency transportation of trade goods and services in terms of reducing time distance and cost. CPEC as a project should not be only limited to economic activities, rather it should contribute to the overall socio-economic development of the region.

Open access
Steel and Concrete Elasto-Plastic Models at Bridges with Steel Beams Embedded in Concrete

Abstract

For new railway bridges with short spans (L ≤ 35.00 m) superstructures with steel beams embedded in concrete are recommended or used, which can ensure the requirements of strength and stiffness in particular, regardless of velocity. They are built relatively easily compared to reinforced concrete structures or steel structures, they have high durability if designed, built and maintained correctly and don’t have high sensitivity to fatigue degradation in service. They are also used for road bridges when it is desired to achieve a reduced construction height.

In all the design prescriptions used so far for structures with steel beams embedded in concrete, the calculation is a simplified one, made on a single insulated longitudinal beam of the deck, if certain conditions related to the geometry of the structure are met (obliquity, curvature). Simplifications are also made regarding the state of deformation of the decks made in this constructive solution by introducing an effective moment of inertia in the displacement calculation, as an average of the inertia moments of the cross section considered to be cracked and respectively un-cracked.

The article aims to validate steel and concrete elasto-plastic models, based on an experiment from the technical literature, necessary for complex analyses of the percentage of concrete involved in the stiffness of the cross-sections, in case of bridges with steel beams embedded in concrete.

Open access
Study on Indirect Tensile Strength of Plastic Waste Bituminous Concrete for Road Construction

Abstract

The rutting and cracking of pavements has become very common problem in India. Also the quantity of plastic waste has significantly increased in the recent year due to industrialization and population growth. Improper disposal of these plastic wastes has caused various environmental problems, hence the alternative use of waste plastic in bituminous concrete for road construction has been encouraged by the community. In the present study the Indirect Tensile Strength Test has been carried out on Marshall Samples confirming to ASTM D6931-12. Three different processes (dry process, wet process and combined process) of mixing of waste plastic were used during experimentation. It was found that the indirect tensile strength (ITS) and tensile strength ratio (TSR) of sample significantly increase up to 8%, 6% and 12% for dry process, wet process and combined process respectively for LDPE and HDPE type of waste plastic.

Open access
Analysis of Delays and Extension of Execution Duration of a Road Project

Abstract

The implementation of road infrastructure projects often results in delays due to objective causes, with repercussions on the final execution deadline and with value implications. The use of critical path method for planning and the executin windows, will result in better time process management and optimization delays.

Open access