Vibrations and aerodynamic stability of a prestressed pipeline cable bridge

A method is presented for analysing the vibrations and aerodynamic stability of a prestressed pipeline cable bridge structure. The structure of the bridge and the method for calculation of the natural vibration frequencies are described. Some of the natural vibration frequencies were tested by measuring dynamic quantities on a bridge structure in situ.A sectional model was designed for testing in a wind tunnel of diameter 1.8 m; the model was investigated by means of a drag balance, and the aerodynamic coefficients C_L, C_D and C_M were determined. The same model was suspended elastically in a wind tunnel and its response to an airstream studied. The results of the measurements for the rigidly and elastically suspended model are used in calculating the critical flutter velocity and in analysing the model's aerodynamic stability.