Supplemental elastic stiffness to reduce isolator displacements for seismic-isolated bridges in near-fault zones

Date

2007-05-01

Author

Dicleli, Murat

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In this paper, the efficiency of providing supplemental elastic stiffness to seismic-isolated bridges (SIBs) for reducing the isolator displacements while keeping the substructure forces in reasonable ranges is investigated. Conventional supplemental elastic devices (SEDs) such as elastomeric bearings placed in parallel with seismic isolators between the superstructure and substructures are used for this purpose. A parametric study, involving more than 400 nonlinear time history (NLTH) analyses of realistic and simplified structural models of typical SIBs are conducted using simulated and actual NF ground motions to investigate the applicability of the proposed solution. It is found that providing SEDs is beneficial in reducing the isolator forces to manageable ranges for SIBs subjected to NF ground motions with moderate to large magnitudes regardless of the distance from the fault. It is also found that the stiffness of the SED may be chosen in relation to the velocity pulse period (or magnitude) of the NF ground motion to minimize the isolator displacements by avoiding resonant response. Further analyses conducted using a realistic structural model of an existing bridge and five NF earthquakes with moderate to large magnitudes confirmed that SEDs may be used to reduce the displacement of the isolators while keeping the substructure base shear forces in reasonable ranges for SIBs located in NF zones.

Subject Keywords

Seismic isolation, Nonlinear response, Near fault, Design, Stiffness, Damper, Displacement, Force

URI

https://hdl.handle.net/11511/49212

Journal

ENGINEERING STRUCTURES

DOI

https://doi.org/10.1016/j.engstruct.2006.06.013

Collections

Department of Engineering Sciences, Article

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Supplemental elastic stiffness to reduce isolator displacements for seismic-isolated bridges in near-fault zones Dicleli, Murat (null; 2007-01-01) In this paper, the efficiency of providing supplemental elastic stiffness to seismic-isolated bridges (SIBs) for reducing the isolator displacements while keeping the substructure forces in reasonable ranges is investigated. Conventional supplemental elastic devices (SEDs) such as elastomeric bearings placed in parallel with seismic isolators between the superstructure and substructures are used for this purpose. A parametric study, involving more than 400 nonlinear time history (NLTH) analyses of realistic...
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Optimum Properties of Seismic Isolation Systems in Highway Bridges to Minimize Isolator Displacements or Substructure Forces Dicleli, Murat (null; 2019-07-06) In this study, closed form equations as functions of the isolator, bridge and ground motion properties are formulated to calculate the optimum characteristic strength, Qd and post-elastic stiffness, kd, of the isolator to minimize the maximum isolator displacement (MID) and force (MIF) for seismic isolated bridges (SIBs). For this purpose, first, sensitivity analyses are conducted to identify the bridge, isolator and ground motion parameters that affect the optimum values of Qd and kd. Next, for the identif...

Citation Formats

M. Dicleli, “Supplemental elastic stiffness to reduce isolator displacements for seismic-isolated bridges in near-fault zones,” ENGINEERING STRUCTURES, pp. 763–775, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/49212.