FULL-SCALE DYNAMIC TESTING OF THE ALAMILLO CABLE-STAYED BRIDGE IN SEVILLE (SPAIN)

Accelerations and displacements due to dynamic excitation by simulated traffic consisting of two trucks, were measured on the deck and tower of the Alamillo cable-stayed bridge. Also the dynamic testing program included the measurement with accelerometers of the free-damped vibration of the 26 cables achieved by means of quick-releasing force. From these measurements it was possible to obtain the dynamic parameters of the bridge (natural frequencies and damping ratios) and the real forces in the cables. In the paper, only the tests, results and conclusions related to dynamic parameters of the bridge are presented. The objective of the dynamic tests herein described was to validate the mathematical modelling and the wind-tunnel models used in the dynamic analysis of the bridge in front of traffic and wind-forces. As the agreement between dynamic parameters of the real bridge and theoretical and scaled models was very satisfactory, the correct dynamic behaviour of the bridge in response to traffic and wind (vortex shedding flutter, etc.) can be deduced jointly with the correct alignment and expected internal forces in the permanent state in tower and deck.