Vergleich und Beurteilung unterschiedlicher Lastmodelle für die Ermittlung der dynamischen Antwort von Zugüberfahrten über Brücken bei Hochgeschwindigkeitsverkehr

Comparison and assessment of various load models to calculate train crossings of bridges at high speed.

Three analytical load models to calculate train crossings over bridges are mathematically formulated: a series of concentrated forces, a series of concentrated masses and a series of multi-body systems. The coupling of the load models to the bridge model is carried out within the scope of a two-dimensional treatment of the problem and without simplifications. The differential equations of motion are discretised using the method of Ritz and Galerkin (modal analysis). The three load models are compared with each other using the example of a lightweight beam bridge made of steel which is loaded by a high-speed train. The example shows clearly that the dynamic response of a lightweight bridge is overestimated if the load models consist of concentrated forces or masses. Even the use of simple multi-body systems with only few degrees of freedom lead to considerably more accurate results. This finding particularly holds true for bridges which are at risk of resonance effects. Options for an efficient calculation are available with modal analysis and are discussed. The assessment of resonance effects is also treated.