The assessment of a bridge’s resistance and performance is directly linked with reliability aspects of both the

resistance and the loading characteristics. Long bridges may be strongly affected by the ground spatial variability

which affects both the resistance characteristics (foundation design), and the loading characteristics, especially

under seismic excitation. The uncertainties pertaining to multivariate idiosyncrasy are discussed, and a generalized

dependence paradigm is suggested in the framework of bridge analysis under asynchronous seismic excitation.