Modal testing of Tamar suspension bridge

Abstract

As part of a continuing investigation on the Tamar Suspension Bridge, vibration measurements on the Tamar Bridge were conducted on two occasions. Using three sensors, the first measurement (in 2005) identified possible deck vibration modes and characterised the performance of new additional stay cables. The second measurement, in 2006, used 16 accelerometers to characterise the motion of main and side spans as well as the towers, by means of identification of a full set of modal parameters (except modal masses). The procedures for these two brief operational modal tests are described with the significance of some of the findings in relation to the 'structural mechanisms' of the bridge.