Modal analysis of a bridge using short-duration accelerations

The application of unmanned aerial vehicle technology to bridge structural health monitoring has become a hot research topic due to its low cost, safety and high energy efficiency. However, flight duration and battery life are substantial technical limitations. Is a short data burst sufficient for damage detection? This paper intends to answer this question by developing a novel approach based on frequency domain decomposition to obtain the mode shapes from a short data burst. Then, the modal assurance criterion is used as an indicator of the differences between the estimated mode shapes from the short data burst and the exact eigenvectors from finite element analysis. Here, the short data burst is obtained from the simulated acceleration response of a bridge beam model due to the crossing of two quarter-cars. A new damage indicator based on the modal assurance criterion profile along the beam is proposed to locate and quantify damage.