Influence of Site and Source Dependent Ground Motion Scenarios on the Seismic Safety of Long-span Bridges in Cologne, Germany

An overlap in frequency between the 1D resonance frequency of sediments and the vibrational frequencies of long-span bridges might lead to a strongly increased structural response of the latter. Interference of surface waves caused by reflections at dipping interfaces may introduce additional unfavourable amplifications. Therefore, the vulnerability of two bridges crossing the Rhine River in Cologne, Germany, was assessed using ground motion scenarios computed for four profiles crossing the Lower Rhine Embayment. Due to their vibrational frequencies being in the vicinity of resonant peaks in the response spectra, the Severinsbridge showed critical loading and the bridge Cologne-Deutz even exhibited grave failure according to the dynamic FE-simulations.