Dynamic characteristics of bridges with short pylons and outwardly inclined cable planes

This study developed a cable-stayed bridge characterised by short pylons and outwardly inclined cable planes. The dynamic characteristics of this bridge were investigated using the Lanczos eigenvalue and finite element methods. The first ten mode shapes and frequencies were analysed to this end. The influences of key parameters, such as the inclination angle of the pylons and the height and stiffness of the cable-pylon anchorage, on the dynamic characteristics of the bridge were examined. The results showed that the transverse bending modes of the main girder occurred first, while modes related to pylons appeared later. The torsional vibrational modes appeared in the 10th order, indicating the bridge had suitable wind resistance. Further, the outwardly inclined cable planes enhanced the lateral seismic resistance of the bridge. Increasing the rigidities of the cable-pylon anchorage and main girder can improve the dynamic characteristics of the bridge. This is accomplished by reducing the height of the cable-pylon anchorage and adding auxiliary piers.