Abstract：In order to investigate the influence of spatial distribution characteristic of near-fault ground motions on the seismic
response of a cable-stayed bridge, Chi-Chi(Taiwan) Earthquake records distributed in Forward District (FD), Middle District (MD) and
Backward District (BD), which are divided based on the position of the sites of the district relative to the fault rupture, are selected
as seismic input. The response spectrum analysis shows that the seismic ground motions in MD and FD district contain abundant low-
frequency component, while the spectral values in BD are generally significant in the short period range. The seismic responses of a
406m-span cable-stayed bridge are analyzed with above seismic ground motions as input. The calculation results show that the bridge
under MD earthquakes has the maximum seismic responses, the displacements at the top of the tower and internal forces at the base of the
tower are 4.03 and 2.0 times than those under BD records, respectively. The average value of longitudinal displacement under FD
earthquakes is 2.06 times that under BD earthquakes, while the average value of moment and shear force decreases 35.5% and 32.2%,
respectively. It is also revealed that different parameters of near-fault ground motions have various correlations with the dynamic
responses of cable-stayed bridge in 3 districts. Numerical results illustrate that the seismic design of structures in MD should take
into account higher strength and deformation demand. The parameters, such as PGV and PGA value, can be selected as intensity indices to
evaluate the dynamic seismic responses of structures, and seismic ground motions in the reasonable direction should be selected. The
input energy and PGA have significant influence on the dynamic seismic responses of structures in FD, so structural deformation should
be restricted in the area. For the structures in BD, strength demand should be highlighted,and fault distance and PGV can be
selected as preferable evaluation parameters of the near-fault ground motions.
