Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Dynamic analysis of a portal frame railway bridge using frequency dependent soil structure interaction
With the development of high-speed railroads the dynamic behaviour of railroad bridges is increasingly important to explore. Deeper knowledge about the influence of different factors and what should be included in a model is essential if the designer shall be able to make reliable estimates of responses in existing and new structures. One factor is the soil-structure interaction (SSI), describing how the foundation of the bridge and the soil properties affect the behavior of the bridge under dynamic loading. In this thesis, the influence of including SSI in a model of a portal frame railway bridge is studied, and an analysis procedure in the frequency domain for models with frequency-dependent boundary conditions is described. A 3D finite element model of an e isting bridge has been built up, based on the theory of linear elasticity. The model has been given three different types of boundary conditions: clamped, static stiffness and frequency-dependent stiffness from SSI. Results from simulated train passages, with a train set consisting of two wagons, were compared for the different boundary conditions. The models have also been compared with measurement data from the bridge, which has given indications about which model describes reality in the best way. The results show that the model in which SSI is included by frequency dependent boundary conditions is in slightly better agreement with measurement data than the clamped model and the model with static stiffness. The model gives a slightly better damping of the free vibrations and the natural frequencies correspond better with experimental data. The difference in maximum acceleration from a train passage is very small between the different models, even if it is found that the clamped model generally has lower accelerations and hence is non-conservative. It appears that the train speed affects the maximum acceleration, the size of the free vibrations and the natural frequencies that are present in the free vibrations in the models. Further studies are ...
Dynamic analysis of a portal frame railway bridge using frequency dependent soil structure interaction
With the development of high-speed railroads the dynamic behaviour of railroad bridges is increasingly important to explore. Deeper knowledge about the influence of different factors and what should be included in a model is essential if the designer shall be able to make reliable estimates of responses in existing and new structures. One factor is the soil-structure interaction (SSI), describing how the foundation of the bridge and the soil properties affect the behavior of the bridge under dynamic loading. In this thesis, the influence of including SSI in a model of a portal frame railway bridge is studied, and an analysis procedure in the frequency domain for models with frequency-dependent boundary conditions is described. A 3D finite element model of an e isting bridge has been built up, based on the theory of linear elasticity. The model has been given three different types of boundary conditions: clamped, static stiffness and frequency-dependent stiffness from SSI. Results from simulated train passages, with a train set consisting of two wagons, were compared for the different boundary conditions. The models have also been compared with measurement data from the bridge, which has given indications about which model describes reality in the best way. The results show that the model in which SSI is included by frequency dependent boundary conditions is in slightly better agreement with measurement data than the clamped model and the model with static stiffness. The model gives a slightly better damping of the free vibrations and the natural frequencies correspond better with experimental data. The difference in maximum acceleration from a train passage is very small between the different models, even if it is found that the clamped model generally has lower accelerations and hence is non-conservative. It appears that the train speed affects the maximum acceleration, the size of the free vibrations and the natural frequencies that are present in the free vibrations in the models. Further studies are ...
Dynamic analysis of a portal frame railway bridge using frequency dependent soil structure interaction
Arvidsson, Therese (Autor:in) / Li, Jiajia (Autor:in)
01.01.2011
328
Hochschulschrift
Elektronische Ressource
Englisch
Simplified analysis of the dynamic soil–structure interaction of a portal frame railway bridge
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