Effects of Pier and Deck Flexibility on the Seismic Response of Isolated Bridges

The seismic response of bridges isolated by elastomeric bearings and the sliding system is investigated under two horizontal components of real earthquake ground motions. The selected bridges consist of multispan continuous deck supported on the piers and abutments. Three different mathematical models of the isolated bridge are considered for the analytical seismic response by considering and ignoring the flexibility of the deck and piers. The mathematical formulation for seismic response analysis of various mathematical models of the bridges isolated by different isolation systems is presented. The accuracy and computational efficiency of various mathematical models of isolated bridges is investigated by comparing their responses under different system parameters and earthquake ground motions. The important parameters selected are the flexibility of deck, piers, and isolation systems. There was significant difference in the computational time required for different models, but it was observed that the seismic response of the bridges obtained from different equivalent mathematical models is quite comparable even for an unsymmetrical bridge. Thus, the earthquake response of a seismically isolated bridge can be effectively obtained by modeling it as a single-degree-of-freedom system (i.e., considering the piers and deck as rigid) supported on an isolation system in two horizontal directions.

[1]  C. V. Anderson,et al.  The Federal Emergency Management Agency (FEMA) , 2002 .

[2]  Vasant Matsagar,et al.  Influence of isolator characteristics on the response of base-isolated structures , 2004 .

[3]  L. H. Sheng,et al.  Equivalent elastic seismic analysis of base-isolated bridges with lead-rubber bearings , 1994 .

[4]  Yozo Fujino,et al.  Performance evaluation of base-isolated Yama-agé bridge with high damping rubber bearings using recorded seismic data , 2001 .

[5]  Ian D. Aiken,et al.  AN ANALYTICAL HYSTERESIS MODEL FOR ELASTOMERIC SEISMIC ISOLATION BEARINGS , 1997 .

[6]  R. S. Jangid.  SEISMIC RESPONSE OF ISOLATED BRIDGES , 2004 .

[7]  Yasuki Ohtori,et al.  Evaluation of laminated rubber bearings for seismic isolation using modified macro-model with parameter equations of instantaneous apparent shear modulus , 1999 .

[8]  Athol J. Carr,et al.  DEVELOPMENT OF A DESIGN PROCEDURE FOR BRIDGES ON LEAD-RUBBER BEARINGS , 1989 .

[9]  Michael C. Constantinou,et al.  Sliding Isolation System for Bridges: Experimental Study , 1992 .

[10]  Michael C. Constantinou,et al.  Sliding Isolation System for Bridges: Analytical Study , 1992 .

[11]  Michael C. Constantinou,et al.  3D-BASIS-ME:Computer Program for Nonlinear Dynamic Analysis of Seismically Isolated Single and Multiple Structures and Liquid Storage Tanks , 1994 .

[12]  Wei-Hsin Liao,et al.  SEISMIC RESPONSE ANALYSIS OF BRIDGES ISOLATED WITH FRICTION PENDULUM BEARINGS , 1998 .

[13]  Ahmed Ghobarah,et al.  SEISMIC PERFORMANCE OF HIGHWAY BRIDGES , 1988 .

[14]  Stephen A. Mahin,et al.  A Simple Pendulum Technique for Achieving Seismic Isolation , 1990 .

[15]  T. K. Datta,et al.  Nonlinear Response of Torsionally Coupled Base Isolated Structure , 1994 .

[16]  Michael C. Constantinou,et al.  Nonlinear Dynamic Analysis of 3‐D‐Base‐Isolated Structures , 1991 .

[17]  R. S. Jangid,et al.  Seismic response of isolated bridges with soil-structure interaction , 2003 .

[18]  P. TSOPELAS,et al.  Experimental study of FPS system in bridge seismic isolation , 1996 .

[19]  J. M. Chiou,et al.  An equivalent linear model of lead-rubber seismic isolation bearings , 1996 .

[20]  R. S. Jangid,et al.  Seismic behavior of isolated bridges: A-state-of-the-art review , 2003 .

[21]  Li Xiaoming.  Optimization of the stochastic response of a bridge isolation system with hysteretic dampers , 1989 .

[22]  Y. K. Wen,et al.  Random vibration of hysteretic systems under bi‐directional ground motions , 1986 .

[23]  R. S. Jangid.  SEISMIC RESPONSE OF SLIDING STRUCTURES TO BIDIRECTIONAL EARTHQUAKE EXCITATION , 1996 .