01046013

Component

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 at 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 at reasonable ranges for SIBs located in NF zones.

01042056

07-0856

English

17p

2007

Transportation Research Board 86th Annual Meeting

CD-ROM

Figures (10) ; References (26) ; Tables (1)

Bridge design; Bridge engineering; Bridge members; Bridge superstructures; Bridges; Earthquake resistant design; Elasticity (Mechanics); Fault location; Fault tolerance; Retrofitting; Seismic prospecting; Seismicity

Isolated bridges; Seismic isolation (Bridge engineering)

Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls

Transportation Research Board Annual Meeting 2007 Paper #07-0856

TRIS, TRB

Feb 8 2007 5:25PM