Seismic performance comparison of two rocking isolation alternatives for an overpass bridge
Vassiliou, Michalis F.Show all
- Conference Paper
Rights / licenseIn Copyright - Non-Commercial Use Permitted
Rocking isolation of structures is evolving as an alternative design concept in earthquake engineering. The present paper investigates the seismic performance of an actual overpass bridge of the Attiki Odos motorway (Athens, Greece), employing two different concepts of rocking isolation: (a) rocking of the piers on the foundation (rocking piers); and (b) rocking of the pier and foundation assembly (rocking footings) on the soil. The examined bridge is an asymmetric 5-span system having a continuous deck and founded on surface foundations on a deep clay layer. The seismic performance of the two rocking isolated bridges is compared to that of the existing bridge, which is conventionally designed according to current seismic design codes. To that end, 3D numerical models of the bridge–foundation–abutment–soil system are developed, and both static pushover and nonlinear dynamic time history analyses are performed. For the latter, an ensemble of 20 records (10 ground motions of 2 perpendicular components each) that exceed the design level are selected. The conventional system collapses in 5/10 of the (intentionally severe) examined seismic excitations. The rocking piers design alternative survives in 8/10 of the cases examined, with negligible residual deformations. The safety margins of the rocking footings design concept are even larger, as it survives in all examined cases. Both rocking isolation concepts are proven to offer increased levels of seismic resilience, reducing the probability of collapse and the degree of structural damage. Nevertheless, in the rocking piers design alternative high stress concentrations at the rotation pole (pier base) are developed, indicating the need for a special design of the pier ends. This is not the case for the rocking footings concept, which however is subject to increased residual settlements but no residual rotations. Show more
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Book titleProceedings of the 16th European Conference on Earthquake Engineering (16ECEE)
Pages / Article No.
PublisherEuropean Association for Earthquake Engineering
SubjectEarthquake engineering; Rocking isolation; Seismic Isolation; bridge engineering
Organisational unit09569 - Anastasopoulos, Ioannis / Anastasopoulos, Ioannis
02607 - Institut für Geotechnik / Institute for Geotechnical Engineering
09663 - Vassiliou, Michalis / Vassiliou, Michalis
NotesProceedings only distributed to conference participants.
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