Railway bridges damping identification using traffic induced vibration

this paper presents some results obtained whilst identifying railway bridges damping using traffic induced vibration. In order to enhance the results obtained by the classical logarithmic decrement method, two parametric methods - AR and Eigen Value method - are proposed. These methods are very efficient and can identify damping of several close modes. Application of these methods-to real life measurement gives good results, and damping can be estimated for some modes, in some cases where logarithmic decrement is not applicable. A further development consists in measuring the damping variation during the response decay which allows a more comprehensive approach of damping measurements.