<p>Monitoring the health of critical structures like truss systems has been a key focus for researchers in recent decades due to the growing number of constructed facilities and the associated risks of structural failures. This article introduces a testing method employing a moving source to identify damaged elements within the truss. By analyzing the vibration data collected from each nodal point of the truss, damaged elements are pinpointed through data processing. The technique involves evaluating the Cumulative Damage Index (TDI) values derived from time and frequency domain analyses of nodal velocity responses recorded at upper nodes of the structure. Validation of this damage detection approach is conducted using seismic data obtained from a real truss structure and synthetic data generated through numerical simulations. A three-dimensional truss structure with dual spans is used in the laboratory for this purpose, and various numerical analyses are carried out. The findings demonstrate that the moving source method facilitates precise identification of failure locations and severity levels. Notably, an increase in TDI values at nodes correlates directly with a rise in damage severity within the affected member. However, the TDI pattern varies across different scenarios, with values changing based on the damaged member’s position. Consequently, the TDI parameter serves as a valuable indicator for pinpointing the location and extent of damage throughout the structure during moving source tests.</p>