Estimation of Damping Matrices of Cable-Stayed Bridges Based on Known Data of Modal Damping

The composition of damping in cable-stayed bridges is complicated. It is difficult to determine the damping matrices precisely. A method to calculate the estimation of damping matrices of cable-stayed bridges by known damping ratios is proposed in this paper. Based on the assumption that the damping coefficients of substructures (i.e. Girder, tower, cable, support etc.) in cable-stayed bridges don't change with frequency or amplitude of vibration, the complex eigenvector and natural frequency of cable-stayed bridges are derived by non-proportional damping state-space method. The results have high precision, which fulfill the requirement of dynamic calculation of structures. The damping matrices have more information than modal damping ratios, which has wide application in reality.