With the aging of many existing structures, damage identification and health monitoring techniques have been considered. In the event of damage detection in the early stages, while preventing the spread of damage and increasing immunity, it can be repaired at a lower cost. However, providing user-friendly techniques to detect damage with low cost and desirable precision, is especially important. A significant number of steel bridges are in service. Due to the increase in years of service as well as traffic loads, various damage has been caused to them. In addition, the occurrence of some events, more attention to these structures and the development of health monitoring methods for them has been considered more than ever. In the research, an applied technique and a new damage index are proposed to identify damage in steel piers of bridges. The index is based on the CWT and the Pearson's product-moment coefficient. To evaluate the performance of the proposed technique, the FEM model of a large bridge was used. The bridge located at the intersection of Hafez and Enghelab Streets, is one of the most important bridges in the city of Tehran. The bridge model was created based on as built plans, site investigations and field studies. According to the results, the proposed technique with desirable precision can detect damage in steel piers. Due to the simplicity of the technique, needless to the structural characteristics, high performance and favourable results, using the technique to identify damage in steel piers of bridge is recommended.