Validation of an analytical displacement-based pushover for multi-span continuous deck bridges

In the framework of seismic vulnerability assessment, the displacement-based analytical approaches allow the investigation of the non-linear response of structures with accuracy and low computational effort. This paper deals with a recently-proposed displacement-based analytical pushover addressed to the seismic performance assessment of multi-span continuous-deck straight bridges. The method consists in the static analysis of a simplified mechanical model for increased displacements (pseudo pushover) and allows to obtain an "adaptive" force-displacement curve. This procedure is applied to a set of 36 short bridge configurations representing typical Italian typologies (2 to 6 bays, with two deck configurations and different height of the piers). This work aims to test the method for different hazard intensities, also discussing the influence of bridge regularity in the predicted seismic performance. The accuracy of the DBA procedure is evaluated comparing it with more refined pushover and non-linear time history analyses. Three different suites of 10 natural ground motions, scaled to different intensity levels, are adopted. The results are discussed in terms of capacity/demand checks and predicted deformed shape, proving that the DB pseudo pushover provides approximately the same level of accuracy expected for standard non-linear static analyses.