Damage Detection of Bridge Beam Structures under Moving Loads

System identification technique is used widely in the damage assessment of engineering structures. It is regarded as the key part of a structural health monitoring system, which identifies the physical parameters from the raw measurement data. The changes in the identified parameters will be used to assess the damage of the structure. Most system identification methods need the input loading and output response information. However, the input excitations, such as wind forces, traffic or earthquake loads are usually unknown or difficult to be accurately measured under actual operating conditions. This is particularly true for large civil engineering structures such as buildings, long bridges and offshore structures. System identification techniques using measured structural responses only to identify modal or structural parameters invoked great interests in the past few decades. In this paper, a novel method to detect the damage in bridge beam structures under load environment is developed. The load environment is modelled by a group of vehicle-bridge interaction forces moving at a prescribed velocity, and the bridge is modelled as a simply supported Euler-Bernoulli beam. Numerical simulations show the method is effective to identify the damage in the bridge structures.