City Research Online

Abstract

The present study explores analytically the concept of rocking isolation in bridges considering for the first time the influence of the abutment-backfill system. The dynamic response of rocking bridges with free-standing piers of same height and same section is examined assuming negligible deformation for the substructure and the superstructure. New relationships for the prediction of the bridge rocking motion are derived, including the equation of motion and the restitution coefficient at each impact at the rocking interfaces. The bridge structure is found to be susceptible to a failure mode related to the failure of the abutment-backfill system, which can occur prior to the well-known overturning of the rocking piers. Thus, a new failure spectrum is proposed called Failure Minimum Acceleration Spectrum (FMAS) which extends the overturning spectrum put forward in previous studies and it differs in principle from the latter. Parametric analyses are conducted with respect to the stiffness of the backfill, highlighting the importance of stiff profiles in rocking response of bridges. The comparison with the dynamic response of bridges modelled as rocking frames without abutments reveals that seat-type abutments and their backfill have a generally beneficial effect on the seismic performance of rocking pier bridges, but also that the simple frame model cannot capture all salient features of the rocking bridge response, as it misses potential failure modes, overestimating the rocking bridge’s safety when these modes are critical.

Publication Type:	Article
Additional Information:	© 2020 The Authors. Journal of Product Innovation Management published by Wiley Periodicals LLC on behalf of Product Development & Management Association This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
Publisher Keywords:	Rocking bridges, self-centring, abutment, backfill, seismic isolation, analytical dynamics
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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