Damage Detection of Truss Bridges Using Wavelet Transform of Rotation Signal

Although some researchers indicated that the rotation response of the structure is a proper index to identify the damage location, Wavelet Transform (WT) of rotation response of the bridge is not yet used to detect the damage location in the previous studies. In this regard, a numerical model of a truss bridge was developed using finite element method. The static response of the model under one point-load and a six-axle locomotive was calculated. The response obtained from the model was compared with that of the literature to investigate the validity of the model developed in this study. The WT coefficients of horizontal, vertical and rotation responses of each member of the bridge were obtained based on the Gaus2 wavelet basis function. Several damage scenarios were considered for the bridge to investigate the effectiveness of WT of rotation response of the bridge to detect the damage location. The obtained results show that the WT of horizontal displacement is not a proper index to detect the damage in the bridge members. A Comparison between WT coefficients of vertical displacement and rotation for all members indicates that the rotation response is a proper index to identify the damage and loading locations. In some cases, while the damage causes a significant jump on the WT coefficients of rotations of the members, the WT coefficients of vertical displacement of these members are not influenced by the damage.