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Interaction between Bridge Structure and Continuous Welded Rail
Vendel, Jiří ; Salajka, Vlastislav (referee) ; Ryjáček,, Pavel (referee) ; Plášek, Otto (advisor)
Understanding the interaction between a continuous welded rail and bridge structure is knowledge of all influences that participate in mutual coaction. Besides the material and cross-sectional characteristics of the bridge belonging to the scope of bridge design, there are several circumstances derived from external loads which have to be taken into account when designing new systems and assessing existing ones. From the physical point of view, each material has a natural tendency to change in length when the internal temperature changes. The continuous welded rail, concretely its central fixed zone, does not have this possibility due to its principle. However, if it is located on a bridge that freely expanse, the situation is significantly different. Due to the thermal expansion as well as the effects of railway transport, the bridge contributes significantly to the position and stress of the track. Usually, the most observed part of the continuous welded rail is the area above the sliding bearings of the bridge, where extremes of displacement and stress occur. Not only longitudinal expansion but also the rotation of the end of the supporting structure are the main sources of stresses at this point. This is because of the vertical load of the railway combined with the effects of traction and braking. If the exact degree of interaction between the bridge structure and the track (known as the longitudinal resistance of the track) were known, the design of a new or assessment of the existing system would have a better informative value, and we would not commit undesirable inaccuracies resulting from general normative provisions. It has been tested by many years of experience that from an operational and economic point of view, it is undoubtedly advantageous and desirable to establish a continuous welded rail wherever circumstances allow. So the goal of the research efforts is to approach more faithfully the real length limits of the bridge structure, in which
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Interaction between Bridge Structure and Continuous Welded Rail
Vendel, Jiří ; Salajka, Vlastislav (referee) ; Ryjáček,, Pavel (referee) ; Plášek, Otto (advisor)
Understanding the interaction between a continuous welded rail and bridge structure is knowledge of all influences that participate in mutual coaction. Besides the material and cross-sectional characteristics of the bridge belonging to the scope of bridge design, there are several circumstances derived from external loads which have to be taken into account when designing new systems and assessing existing ones. From the physical point of view, each material has a natural tendency to change in length when the internal temperature changes. The continuous welded rail, concretely its central fixed zone, does not have this possibility due to its principle. However, if it is located on a bridge that freely expanse, the situation is significantly different. Due to the thermal expansion as well as the effects of railway transport, the bridge contributes significantly to the position and stress of the track. Usually, the most observed part of the continuous welded rail is the area above the sliding bearings of the bridge, where extremes of displacement and stress occur. Not only longitudinal expansion but also the rotation of the end of the supporting structure are the main sources of stresses at this point. This is because of the vertical load of the railway combined with the effects of traction and braking. If the exact degree of interaction between the bridge structure and the track (known as the longitudinal resistance of the track) were known, the design of a new or assessment of the existing system would have a better informative value, and we would not commit undesirable inaccuracies resulting from general normative provisions. It has been tested by many years of experience that from an operational and economic point of view, it is undoubtedly advantageous and desirable to establish a continuous welded rail wherever circumstances allow. So the goal of the research efforts is to approach more faithfully the real length limits of the bridge structure, in which
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