A 3D finite element model of the single-tower and self-anchored suspension bridge

the main bridge of Jiangxin island in Nanjing

was established with the software ANSYS to analyze its natural vibration property with the subspace iteration method considering the influence of the geometrical nonlinearity.The method of response spectrum analysis was used to calculate the seismic responses of the bridge under earthquakes in longitudinal

transversal

vertical

longitudinal+vertical

and transversal+vertical directions;and the seismic response on main cross-sections of the bridge were further analyzed in detail.The result shows that the stress at the tower bottom under the transversal earthquake is greater than that under the longitudinal or the vertical earthquake;the stress on the bridge deck under the vertical earthquake is greater than that under the transversal or the longitudinal earthquake;the displacement at the tower top assumes its maximum value under the combination of longitudinal+vertical earthquakes.And it can offer a reference for the seismic analysis of the same type of bridges.