Dynamic performance of twin curved cable-stayed bridges

The dynamic behaviour of two curved cable-stayed bridges, recently constructed in northern Italy, has been investigated by full-scale testing and theoretical models. Two different excitation techniques were employed in the dynamic tests: traffic-induced ambient vibrations and free vibrations. Since the modal behaviour identified from the two types of test are very well correlated and a greater number of normal modes was detected during ambient vibration tests, the validity of ambient vibration survey is assessed in view of future monitoring. For both bridges, 11 vibration modes were identified in the frequency range of 010 Hz, being a one-to-one correspondence between the observed modes of the two bridges. Successively, the information obtained from the field tests were used to validate and improve 3D finite element so that the dynamic performance of the two systems were assessed and compared basing on both the experimental results and the updated theoretical models.