Communications - Scientific Letters of the University of Zilina, 2007 (vol. 9), issue 3
Articles
A Vehicle - Bridge Interaction
Jozef Melcer
Communications - Scientific Letters of the University of Zilina 2007, 9(3):5-10 | DOI: 10.26552/com.C.2007.3.5-10 
The problem of a vehicle - bridge interaction can be followed in the literature since the year 1849. At the early state the analytical methods were applied. The development of computers brings the change in the approach to the used methods of solution. The Finite Element Method and Component Element Method represent the revolution and qualitative jump in the development. They enable to solve very truthful space computing models numerically. The results of numerical computation must by verified by the in situ experimental measurements. Mutual interconnection of numerical and experimental techniques represents the most effective way in the process of...
Fatigue Assessment of Existing Bridge Members
Josef Vican, Jozef Gocal, Branislav Melis
Communications - Scientific Letters of the University of Zilina 2007, 9(3):11-14 | DOI: 10.26552/com.C.2007.3.11-14
Correct consideration of the service load effects plays a very important role on assessment of railway bridges, especially on fatigue assessment. Eurocode EN 1991-2 introduces twelve types of service trains and prescribes their sequel in normal and heavy duty. The service trains, consisting of locomotive and defined number of wagons, are specified by amount of axle forces and distances between them. However, there is no commentary which would illuminate a background of the service trains technical data. Consequently, it is difficult to say how representative the service load models specified in this standard prescription are in comparison with the...
Dynamic Properties of the Railway Track
Milan Moravcik
Communications - Scientific Letters of the University of Zilina 2007, 9(3):15-20 | DOI: 10.26552/com.C.2007.3.15-20
The paper is focused on different aspects of track dynamics and train-track interaction. The dynamic modeling 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. Dynamic properties of the track structure as a whole is described and evaluated including the dynamics of compound train-track system. The dynamic amplification resulting from the simulated passage of the locomotive of the type E 499.0 (85t) is presented.
Reinforced Subbases and Application of Other Chosen Parameters in Sleeper Subgrade Dimensioning
Libor Izvolt, Jan Kardos, Martin Mecar
Communications - Scientific Letters of the University of Zilina 2007, 9(3):21-27 | DOI: 10.26552/com.C.2007.3.21-27
The paper focuses on reinforced subbases which are frequently applied to modernised railway tracks of Slovak Railways (ZSR) despite certain theoretical and normative deficiencies. Based on the evaluation of laboratory measurements other parameters which are to be taken into consideration when dimensioning a sleeper subgrade construction are specified.
Transportation Planning Model
Jan Celko, Marek Drliciak, Andrea Gavulova
Communications - Scientific Letters of the University of Zilina 2007, 9(3):28-32 | DOI: 10.26552/com.C.2007.3.28-32
The traffic congestion represents a very important problem of the cities at present. The results are a frustration of motorists; longer travel times; an increase of accidents and fuel consumption and negative effect to the environment. The transport relations modeling by exact analysis of the real traffic state is a complex solution. This solution enables a determination of the future demands depending on traffic forecast. The article presents the main process of transport modeling based on four-step solution. This process is completed by its practical using in the town of Zlina. The transport relation analyses, the modal split and traffic distribution...
Relation of Temperature Changes in Asphalt Pavements to Pavement Bearing Capacity Evaluation
Jozef Komacka, Martin Korenko, Jaroslav Piala
Communications - Scientific Letters of the University of Zilina 2007, 9(3):33-36 | DOI: 10.26552/com.C.2007.3.33-36
Temperature changes in asphalt pavements have to be taken into account at the diagnostic and evaluation process of pavements bearing capacity. Theoretical calculations resulting from general theory are not suitable for the practical use. Therefore the experimental test section with flexible and semi-rigid pavement was built and the temperatures were measured at different depths. The examples of typical temperature gradients for the hot summer and cold spring day are presented and their similarities are stated. The development of the simple method for the determination of mean temperature of pavement asphalt layers is described and the correction values...
Effects of Structural Integrity on Improving the Resistance to Dynamic Loads
Emilia Juhasova
Communications - Scientific Letters of the University of Zilina 2007, 9(3):37-46 | DOI: 10.26552/com.C.2007.3.37-46
The paper deals with the approaches to the dynamic response analysis when non-linear response of the structure including its partial damage is expected. This concerns the building and other structures executed near transport lines and possibly subjected to seismic effects from transport or earthquakes. Seismic response is here analysed under the action of near field earthquake that was considered and applied as 6DOF seismic input and 2DOF seismic input. A typical reinforced concrete frame with masonry infills was chosen as the prototype for the experimental tests and next analysis. Two storey one bay 1:1 model was tested on a large shaking table with...
Research on Shear Connection Design in Composite Beams
Jan Bujnak, Kazimierz Furtak
Communications - Scientific Letters of the University of Zilina 2007, 9(3):47-50 | DOI: 10.26552/com.C.2007.3.47-50
The paper deals with a way of determining concrete pressure strength when calculating load carrying capacity of steel perfobond strip connectors. This type of strip connectors has been used in composite bridges only recently and no precise methods of calculating them have been worked out so far. The effect of axial forces on bearing capacity of classical stud shear connectors is also given in the paper as a result of research.
Design of Columns Centrically Loaded in Compression
Ruzica R. Nikolic, Jelena M. Veljkovic, Jozef Vican
Communications - Scientific Letters of the University of Zilina 2007, 9(3):51-55 | DOI: 10.26552/com.C.2007.3.51-55
Design of centrically loaded columns by the axial compressive load is considered in this work. The three methods results are compared: theoretical -procedure and calculations according to standards JUS U.E7.081and Eurocode 3. The analysis is illustrated on an example of a column with a complex cross-section. By comparison between the calculated normal stresses and should be allowable stresses for all the three procedures, one can see that the stresses calculated using both standard procedures are significantly smaller than stresses calculated using the theoretical procedure. This shows that the standard procedures of calculations and design are much...
The Load Testing and Numerical Verifying of the Precast Prestressed Girder
Martin Moravcik
Communications - Scientific Letters of the University of Zilina 2007, 9(3):56-62 | DOI: 10.26552/com.C.2007.3.56-62
Precasting can solve complicated structural details, ambitious demands to quality of surface arrangements and manage hard terms filling at present. The prestressed precast girders are produced to 30.0 m span and are distributed for the realization of big shopping centers. The design and realization of the prestressed precast tie-beam for a skeleton system is presented in this paper. The experimental and numerical analyses were performed to verify the safety and reliable acting of the girder for the next service.
The Transport-Production Coordination Problem
Jaroslav Janacek
Communications - Scientific Letters of the University of Zilina 2007, 9(3):63-67 | DOI: 10.26552/com.C.2007.3.63-67
Vehicle route planning process, which follows a transportation problem solution, often provides a system of cyclic routes of vehicles. This system should cover transportation demands of individual network nodes within a middle term period. Due to non-uniform demand distribution over the period, a new problem emerges in particular parts of the period. This problem consists in balancing the sub-period demands and frequencies, with which the individual routes are performed. This new problem denoted as the transport-production coordination problem is studied in this contribution.We described the problem by mathematical programming tools and proposed a...
Competency or Duty - Methods of Selection in Practice
Gabor Fejes
Communications - Scientific Letters of the University of Zilina 2007, 9(3):68-70 | DOI: 10.26552/com.C.2007.3.68-70
My work deals with the connection between selection methods and competencies. It seeks an answer how company managers interpret the notion of competency, how important labour selection is according to those competencies. The choice among these methods is determined by conscious or rather subjective aspects, traditions and company culture. The findings are the partial results of a current, practical research. The subject is of a significant importance, as there are hardly any researches dealing with selection and its methods. However, its practical importance is beyond doubt, since the reason for the efficiency of organizations and the only resource...