Parallel FEM Simulations for Large Infrastructures

Another activity concerning partial differential equations is the analysis of large/complex infrastructures, like a long-span suspension bridge crossing the Bosphorus, by means of large scale parallel FEM simulations.

This research combines methodological and computing aspects which are tackled best in interdisciplinary cooperation adding the know-how of the ATML to the disciplinary background of the partners.

For the investigation of the seismic behaviour of the Second Bosphorus Bridge, Istanbul, which has a length of more than 1 km, partners form Bogazici University, Istanbul, Fachhochschule Aachen and Forschungszentrum Jülich cooperate in the development of a high resolution FEM model and performing different kind of simulations.

The new FEM model was validated by an eigenvalue analysis computing more than one hundred of the eigenmodes and a comparison with the measured modes of this suspension bridge. The good agreement of computation and experimental data proved that the detailed model is a valid representation of the bridge.

In the next step the behaviour of the bridge under the load of two different recorded earthquakes was calculated. The overall performance of the bridge as well as the detailed forces, stresses etc. of critical components were studied and compared to the design loads. The explicit FEM code LS-DYNA is used for these simulations, since all kind of seismic loads can be applied directly in the time domain and the response of the bridge components can be calculated with high spatial and time resolution.

The relevant damage to the bridge during the more severe earthquake motivates further investigations like the introduction of viscous dampers to the existing FEM model. The results show that a sufficient number of high capacity dampers could be used in order to mitigate the impact of bridge deck and towers.