ABSTRACT
Observations from many previous earthquakes have clearly revealed that the seismic spatial variability plays an important role on the dynamical response of extended structures (Kawashima et al. 2009; Wang et al. 2010). The phenomenon of seismic spatial variability stems mainly from three reasons including the wave passage effect, incoherence effect, and local site effect. These variations of seismic characteristics in mountainous area such as southwest China are more obvious than the flat areas due to the complexity of mountainous site topographies. During recent mountainous earthquakes in China, such as the Wenchuan earthquake on 12 May 2008 and Lushan earthquake on 20 April 2013, some investigations have clearly indicated that the seismic spatial variability in southwestern mountain of China has significantly effect on seismic performance of some extended structures, such as long-span and high-pier railway bridges (Jia et al. 2013).
