Dynamic response analysis of a model truss bridge considering damage scenarios

Structural health monitoring plays a key role for maintenance and lifetime extension of bridges under complex loading conditions and damage scenarios. This paper applies vibration-based methods to monitor the structural health of a Warren-type truss bridge. First, acceleration measurements are used to obtain natural frequencies and modal shapes of the bridge by modal identification. Then, a high-fidelity numerical model in a finite element code is calibrated. Damage scenarios with various crack location and severity are considered for a member, and time-domain simulations are carried out to assess the dynamic responses of the bridge under random excitation. An analysis of the acceleration statistics shows that the damaged member displays a more significant increase in accelerations than the intact members, and locations near the supports of the damaged member experience more changes than other locations. This study contributes to a fundamental understanding of bridge dynamics and facilitates development of damage identification methods.