Many structural damages occurs due to breakdown of constituents. The onset of these fractures is usually accompanied by cracks, the spread of which poses a serious threat to their structures and behavior. Accordingly, the methods of diagnosis and detection of cracks have been the subject of much research to date. The existence of cracks changes the natural and mode frequency of seismic deformations, which analyzes these changes by identifying cracks. These methods are known as Structural Health Monitoring (SHM) techniques, which manage and evaluate the expected behavior and performance of structures over the life of the structure. There are various ways to evaluate and identify these changes, each of which has its strengths and weaknesses. These systems should be able to answer questions such as the location of damage and failure to structures. The modern methods of structural health monitoring are based on the dynamic properties of structures, most of which use modal analysis or Fourier series conversion. In the Fourier transform, information is given about the frequencies in a signal, while no information is recorded since a particular frequency occurs. To determine the location of a crack or any other damage of this kind, it is important to know when a particular frequency occurs that Fourier transform in this field is weak. A novel and efficient method of signal analysis, which has been welcomed by researchers in recent years, is called Wavelet Transform (WT) and has great ability to detect all kinds of discontinuities or inconsistencies, such as sudden loss of hardness, loss of performance, and failure. Bridges are one of the most important structural members, so this research will investigate an example of them, because of its historical importance, by the wavelet transform method.
