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Abstract

The paper presents aspects of the design and execution of the Turdas tunnel located on the local variant (route), on the Coşlariu - Simeria section, from the rehabilitation project of Brasov – Simeria railway line, component part of Pan European Railway Corridor IV, for train circulation with maximum speed of 160km/h. The tunnel crosses through alluvial deposits with silt and clay with locally sand layers at the upper part, sand and gravel with water in the middle part and marly silty clay and neogenic marl, with swelling phenomena, at the lower part. The overburden is between 2.00m and 13.00m. The initial project provided execution in underground, on 510.00m in the central area and from surface at both ends, 225.00m at the entrance and 45.00m at the exit. The new optimized project, based on new geological and geotechnical studies, proposed an execution from surface for the entire length of the tunnel. To establish the optimal solution two methods of surface execution and structural solutions were analyzed comparatively: “Cut and Cover” and “Cover and Cut”. The adopted method was “Cut and Cover”, with a structural solution composed of a temporary retaining structure – diaphragm walls with a special internal lining. This has been divided in six sections with different behavioral types, taking into account the ground configuration in longitudinal profile and the geological and geotechnical data. The technological execution phases are presented in detail. To investigate the behavior of this type of structure under soil and swelling actions, three-dimensional finite element analyses were carried out, taking into account the execution phases for each cross section. A monitoring system was provided to verify the stresses in the temporary retaining structure and the internal lining and also to calibrate future calculations.

Abstract

In this paper some aspects regarding the dynamic behavior of footbridge structures under traffic actions correlated with the people’s comfort are presented. The comfort criterion during footbridge passing depends of the frequencies and accelerations of the structure which must be situated between certain limits. If the frequencies and accelerations of the structure are in the critical domains, some measures to modify them must be taken.

Abstract

Car-motorcycle accidents have been reported higher in recent years in Hungary due to increasing number of motorbikes on road. Car-motorcycle collisions mostly lead to fatal and seriously injured accidents mainly due to the vulnerability of motorcyclists and other related factors. The crash investigation studies aim to analyze the main contributing factors that cause fatal road accidents and injury outcomes. The main goal of this study is to evaluate and compare the contributing factors to car-motorcycle accidents in Budapest city by using a microsimulation tool. The procedure utilized the statistical analysis and data sampling to categorize car-motorcycle accidents by dominant accident types based on collision configurations. The police report is used as a data source for designated accidents and simulation models are plotted according to scale (M 1:200). The simulation crash study results observed the main contributing factors to car-motorcycle accidents such as driver behavior, rider behavior and view obstruction. The comprehensive in-depth investigation also found that most of the car drivers and riders could not perform collision avoidance manoeuvres before the collision. This study can help the traffic safety authorities to solve road safety issues by considering the main contributing factors to car-motorcycle collisions. The study also proposes safety measures to avoid car-motorcycle accidents in future.

Abstract

Maintaining the conditions for optimum exploitation of road networks is one of the primary activities of their administrators.

The basic elements for establishing the decision-making act, are obtained by the correct evaluation, from the technical and financial point of view, of what is necessary for the normal unfolding, without interruptions, and in complete safety, of the car traffic.

In the evaluation process, the managers must have at their disposal sufficient information, regarding the technical status of the road network from the administration, when and where it is appropriate to intervene and what maintenance and repairs operations should be performed.

Only in this way, road managers will be able to adopt the appropriate strategy so that the investment reaches the highest rate of return and of course falls within the limits of the allocated funds.

This paper presents A.D.T.S. (Automatic Determination of the Technical Status) application, designed using the Microsoft Access program. The application allows the determination of the technical status of the roads, storage, retrieval, updating and verification of information regarding the technical status of the roads. The information is kept in a road reference table, as a storage model in data banks, which can be used by public road administrators in their work, regarding the scheduling of works and justifying the need to finance road intervention works.

Abstract

In this paper, a rail joint model consisting of three Euler-Bernoulli beams connected via a Winkler foundation is proposed in order to point out the influence of the joint gap length upon the stiffness of the rail joint. Starting from the experimental results aiming the stiffness of the rail joint, the Winkler foundation stiffness of the model has been calculated. Using the proposed model, it is shown that the stiffness of the rail joint of the 49 rail can decreases up to 10 % when the joint gap length increases from 0 to 20 mm.

Abstract

This paper evaluates the possibility of using artificial aggregates from blast furnace slag, considered industrial waste, which can replace, in a certain dosage, the natural aggregates in the composition of an AB 22,4 asphalt mixture. Furthermore, it is presented the possibility to replace the usual filler with powders from industrial wastes such as the desulphurization waste, generated by the combustion of the energetic coal.

Laboratory studies and researches are carried out according to prescribed techniques. For this purpose, for the evaluation of the performance of the asphalt mixture recipes will be evaluated by static and dynamic tests as described in AND 605: 2016.

The results of this study show the possibility of using asphalt mixtures with different dosages of industrial wastes in composition.

The results obtained from the laboratory tests have shown that materials from industrial waste can be used in the design of asphalt mixtures with the purpose of replacing natural materials, used in certain dosages, which demonstrates good behavior in interaction with the usual bituminous binder.

Abstract

The problem of combating urban noise is closely linked to the rational transformation of the urban environment, which must go through the elimination or reduction of the number of sources of noise, the localization of the noise emission zone, reducing the level of sound sources and protection against noise for the residential areas. Theoretical and experimental studies of acoustic loading on the territory along the highway for the typical section of the urban territory have been conducted. To estimate the complex noise impact from all sources and from individual sources, as well as to predict the total noise exposure for this site, a noise map was constructed using software. As a measure to combat traffic noise in the territory along the highway, the location of the noise protection screen was justified, taking into account the loss of part of the national income as a result of the continuous impact of noise on a person.The results of the research allow to assess the degree of technogenic impact of noise pollution during the operation of the highway, which allows regulating, by administrative and legislative methods, the nature of the impact on natural objects and human health of certain types of activities, as well as reasonably proposing measures that ensure environmental safety when organizing urban streets traffic.

Abstract

Segment videos were produced at different peaks to reflect different sampling criteria like land use characteristics, trails, Ciclocarrils and Ciclovia. Each segment was filmed for 20–40 seconds during bicycle rides at a speed of about 5km/h with a camera strapped, at an angle of 45 degrees, on the head. Curb lane variables such as bicycle pathway widths, curb lane motorised volume (veh/h) and vehicle speed (km/h), bicycle volume on segment, and median width were recorded in addition to secondary data. About 1,360 ratings were acquired from study participants and used in the estimation process. Ordered probability models were used to estimate random parameters of cyclists LOS perception to account for unobserved heterogeneity for all respondents. The deviance (1.085) and Pearson Chi-Square (2.309) with 1,635 degree of freedom at 0.05 level of significance shows that our model provides a better fit of the data. The study observed that BLOS was strongly influenced by side path separation, vehicle speed, motorised traffic volume and conflicts with pedestrians. However, many other factors were found to have high probabilities to influence level of service with unit change. They include bicycle lane width, wide outside lane, pavement conditions, trees and benches, daylight, gender and experience of cyclist. The impact of the variety of observed factors affecting bicyclists reveal the nature and character of urban transportation in Bogota which suggests a range of important trade-offs in further planning and management of the Cicloruta bicycle paths.

Abstract

Moisture-sensitive or collapsible soils are materials with high porosity that under the loads transmitted by the superstructure or even under its own weight present additional settlements once the soil is saturated. This category includes loess deposits and other high silt content soils with uneven porosity. A method often used for foundation on these soils is the realization of local loessoid material compacted columns. This paper presents, on one hand, the experimental laboratory programs aiming to achieve some optimal mixtures of local material (loess) and different other materials (sand, bentonite, cement) in order to improve the values of the mechanical parameters of the soil and so, to limit the settlements. On the other hand, it presents a lot of settlement calculations for different case scenarios.