RC VIADUCTS: PUSH-OVER VERSUS INELASTIC TIME-HISTORY ANALYSES

Several cases of four span viaducts, supported by single-column bents were analyzed. Two different types of constrains (pinned and free) at the abutments were considered, The results of the N۲ method were compared with the results, obtained from inelastic time-history analysis. N۲ procedure combines inelastic static (push-over) analysis of the MDOF system and inelastic dynamic analysis of an equivalent SDOF system. In general, the N۲ method was able to provide reliable estimates of global seismic response of regular bridges. However, in some cases, it failed to predict the actual response. This was particularly true in the cases when the influence of higher modes were important and in torsionally sensitive viaducts. In torsionally sensitive, asymmetric viaducts with rollers at the abutments, the inelastic time-history analysis resulted in nearly uniform distribution of displacements in transverse direction, while the N۲ method indicated much larger displacements at the flexible side of the structure