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Advances in Materials Science and Engineering
Volume 2016, Article ID 1897045, 18 pages
http://dx.doi.org/10.1155/2016/1897045
Research Article

Seismic Behavior of RNC-Isolated Bridges: A Comparative Study under Near-Fault, Long-Period, and Pulse-Like Ground Motions

1SENER Ingeniería y Sistemas, 08290 Barcelona, Spain
2Structural Engineering Department, Zagazig University, Zagazig 44519, Egypt
3Universitat Politècnica de Catalunya-BarcelonaTECH, 08034 Barcelona, Spain
4Applied Mathematics III Department, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
5Construction Engineering Department, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain

Received 22 August 2015; Revised 14 December 2015; Accepted 20 December 2015

Academic Editor: Francisco J. Molina

Copyright © 2016 Mohammed Ismail et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper introduces a recent seismic isolation system, named Roll-in-Cage (RNC) isolator, for efficient protection of bridges against destructive earthquakes. The RNC isolator is a rolling-based isolation system with several integrated features in a single unit providing all the necessary functions of vertical rigid support, horizontal flexibility, full stability, hysteretic energy dissipation, and resistance to minor vibration loads. Besides, it is distinguished by a self-stopping (buffer) mechanism to limit the peak bearing displacement under abrupt severe excitations, a linear gravity-based self-recentering mechanism to prevent permanent dislocations after excitations, and a notable resistance to axial tension. A three-span box-girder prestressed concrete bridge is investigated under a set of different destructive real and synthetic earthquakes including near-fault, long-period, and pulse-like ground motions. As a performance measure, the responses of isolated and nonisolated cases are compared. In addition, the RNC isolator’s behavior is then compared with those of other isolation systems including HDB, FPS, and LRB. The results confirmed that the RNC isolator has a superior behavior in achieving a balance between the peak displacements and accelerations of the isolated deck, relative other isolation systems, besides being the most (relatively) efficient isolator in the great majority of studies performed.