engleski

Experimental analysis of vibrations of the Dubrovnik bridge

Paper presents the testing results of modal parameters of the Dubrovnik bridge superstructure and each cable. These testings were a part of the standard and detailed inspection of the bridge which was extended to these dynamic testings due to vibration of cables under certain wind conditions. The measuring was carried out using highly precise accelerometers in combination with electronic integrators and fast A/D converter, with a 16-bit resolution. Experimental analysis of acquired data was processed using PC portable computer and software with FFT analyzer. Theoretical analysis of natural frequencies of the superstructure was carried out using numerical model made of plate and beam finite elements. The results were directly compared graphically and tabularly. Very good agreement is found between compared theoretical and experimental results. Measured natural frequencies of the cables were used to determine cable forces which were then compared with the forces from the protocol of prestresing during construction. Experimentally determined frequencies are important starting parametrer for the future diagnostics of the bridge state and a very good parameter for numerical simulation of the dynamic behaviour of the bridge.

cable; bridge; vibration; frequencies; modes; damping; forces

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