Communications - Scientific Letters of the University of Zilina, 2004 (vol. 6), issue 3
Articles
Stress and compressibility calculation in subsoil of high embankments and effectiveness of speeding up subsoil consolidation
Marian Drusa, Nguyen Giang
Communications - Scientific Letters of the University of Zilina 2004, 6(3):5-9 | DOI: 10.26552/com.C.2004.3.5-9 
When designing a project of speeding-up consolidation of subsoil of high embankments, there are some influences that cannot be missed. Especially in geotechnical engineering, we have to work with influences and uncertainties that have origin in geological space and surveying possibilities. On a practical example we present a possible way of subsoil stress and compressibility calculation and influence of different input data on necessary time of 90% consolidation of subsoil of one leg of a high embankment that has impact also on design distance and amount of sand piles or geodrains.
Vertical track stiffness effect on dynamic behaviour of track structure
Milan Moravcik
Communications - Scientific Letters of the University of Zilina 2004, 6(3):10-16 | DOI: 10.26552/com.C.2004.3.10-16
The dynamic modelling of railway track response and of the interaction of vehicle and track at low and mid frequencies that are significant for the track deterioration, is presented. The response of the track subjected to a moving vehicle is simulated for a stationary randomly distributed ballast stiffness with a standard uniform distribution and a normal distribution. The response of the track components is solved by the Finite Element Method. Monte Carlo simulation was applied to estimate the dynamic track response. The dynamic amplification resulting from the simulated passage of the locomotive of the type E 499 (85 t) is presented.
Mutli-element system reliability using markov chain model
Peter Kotes, Josef Vican
Communications - Scientific Letters of the University of Zilina 2004, 6(3):17-21 | DOI: 10.26552/com.C.2004.3.17-21
Up to now our researches have focused on determining the existing bridge element reliability level. However, the real structures occurring in practice are not just one-element structures, but they are a set of multiple elements with various signification of single element in structure. On this account, current research activities were focused on determining multi-element structure reliability level. In the presented paper, the steel grid system with m-elements subjected to bending was considered. The Markov chain models were used to calculate structure reliability. The results are compared with analytic solution of system reliability. Analogously,...
Shear capacity of rc beams strengthened with externally bonded frp composite sheets
Patrik Kotula, Stefan Zemko
Communications - Scientific Letters of the University of Zilina 2004, 6(3):22-27 | DOI: 10.26552/com.C.2004.3.22-27
The strengthening of concrete structures using fibre reinforced polymer (FRP) materials has become a growing area in the construction industry over the last few years. Valuable research work is going on all over the world.This work is focused on theoretical, numerical and experimental analysis of the RC beam strengthened with a carbon fibre reinforced polymer (CFRP) sheet of the MBT-MBrace CF 640 type in a shear span of the RC beam.The aim of this paper is to present a simple design approach of calculation of a CFRP sheet contribution to the shear capacity of the RC beams and to compare results with values obtained from numerical analysis based on...
Evaluation of pavement friction according to european standards
Jan Celko, Matus Kovac
Communications - Scientific Letters of the University of Zilina 2004, 6(3):28-30 | DOI: 10.26552/com.C.2004.3.28-30
Pavement friction was measured in Slovakia by SKIDDOMETER BV 11. An evaluation of skid resistance by Mu index value for use in the Slovak Pavement Management System (PMS) is based on one parameter of friction, only. The tendency to adapt the Slovak PMS to European standards involves creation of criteria for the skid resistance evaluation by International Friction Index IFI. The Slovak SKIDDOMETER BV11 did not participate in the PIARC harmonisation experiment for pavement friction measurement. Therefore the new approach for IFI calculation was required. The PIARC experiment and concerned equipment were analysed in detail. The British Portable Tester...
Climatic characteristics and the temperature regime of asphalt pavements
Jan Corej, Martin Korenko, Eva Remisova
Communications - Scientific Letters of the University of Zilina 2004, 6(3):31-36 | DOI: 10.26552/com.C.2004.3.31-36
Traffic density and climate are important external factors influencing pavement mechanics. Climatic conditions influence the service life of materials, damage to roads etc. In many countries the climatic characteristics are implemented into calculation systems for pavement construction. The importance of the implementation of climate characteristics into the calculation systems is increasing in the context of global climatic processes and changes, especially the changes in air temperature. The aim of the following paper is to highlight the changes of climatic characteristics used in highway engineering and their effect on the change of pavement thermal flow.
Experimental verification of railway substructure with application of reinforced geocomposite
Libor Izvolt, Martin Mecar
Communications - Scientific Letters of the University of Zilina 2004, 6(3):37-43 | DOI: 10.26552/com.C.2004.3.37-43
In the paper the authors present results of experimental measurements realized in a testing stand which was built for evaluation of reinforced effect of geocomposite MACRIT GTV/50-50 B applied into a railway substructure. Methodology of experimental measurements, observed physical characteristics of used grounds and results of static loading tests for various granularity and thickness of subbase material (150 mm -600 mm) are described. The main result of the experimental evaluation of two-tested subbase materials is a proposal of nomograms for dimensioning the railway substructure with application of topical geosynthetic material.
Experimental and mathematical analysis of a multi-layer system of railway track
Hana Hana Krejcirikova, Martin Lidmila
Communications - Scientific Letters of the University of Zilina 2004, 6(3):44-46 | DOI: 10.26552/com.C.2004.3.44-46
Based on experimental measurement of a model of a multi-layer non-linear system with inserted geosynthetic layers of the permanent way structure, a new design method will be designed for dimensioning the sleeper subgrade structure using classical and geosynthetic materials or sub-ballast vibration-damping matting. The results of measurements on a track structure model in a 1:1 scale performed in a testing box will be verified by means of a numerical model. A two-dimensional solution will be subsequently verified by means of a spatial model. Numerical modelling will serve for transferring the values measured on the experimental model into a current...
GIS application for solution of the problems of public transportation system in Zilina
Dana Sitanyiova, Sona Masarovicova
Communications - Scientific Letters of the University of Zilina 2004, 6(3):47-50 | DOI: 10.26552/com.C.2004.3.47-50
The paper deals with the public transportation system in Zilina. The research study initiated by the Transportation Company of Zilina has been performed with the aim to solve the problems concerning public transportation service in the urban area. The main goal of the research study was to evaluate how well the bus stops serve the public and to identify the segments of the traffic routes, which are risky for buses and trolleybuses operation. Geographic information system was applied to solve these problems by analysing the geospatial data referring to the transportation system. The paper includes the outputs from these analyses.
Geotechnical aspects of railway tunnel construction near rudoltice
Marian Drusa, Vladimir Grof
Communications - Scientific Letters of the University of Zilina 2004, 6(3):51-54 | DOI: 10.26552/com.C.2004.3.51-54
Construction of the tunnel in Trebovice v Cechach has been, from the geotechnical aspect, the most problematic issue ever, and, we would like to define some of the reasons and to sketch a potential solution.
Reliability of electrical security systems in external protection of the military objects
Tatiana Olejnikova
Communications - Scientific Letters of the University of Zilina 2004, 6(3):55-60 | DOI: 10.26552/com.C.2004.3.55-60
In this paper electrical security systems used in military objects and areas of the Slovak Republic Armed Forces are described. There is described a method of reliability calculation of the safety system elements as a probability that the system will operate without a failure during the defined time in the given conditions.