Effects of the restrainer upon bridge motions under seismic excitations

Dynamic responses of a multi-span simply supported bridge retrofitted with cable restrainers between longitudinally adjacent girders are examined under seismic excitations. A simplified and idealized mechanical model is adopted and the corresponding analysis tools are developed to examine the effects of restrainers, in which the nonlinear behavior as well as the fracture of the cable are considered. Using the proposed model, the effects of the cable length, the stand-by clearance length, and the stiffness of the restrainer upon the global seismic behaviors are verified. The variations of the pounding forces between adjacent girders are evaluated to see the overall effect of the application of restrainers, and the corresponding shear forces and bending moments on each pier are investigated. The main effect of restrainers upon global bridge motions is found to constrain and redistribute the relative distances between adjacent vibrations units. It is also found that the cable length, clearance length, as well as cable section area should be selected properly depending on the level of seismic intensity.

[1]  Gregory A. MacRae,et al.  P-Δ Effects on Single-Degree-of-Freedom Structures in Earthquakes , 1994 .

[2]  Demeter G. Fertis,et al.  Mechanical And Structural Vibrations , 1995 .

[3]  Silvia Dimova,et al.  Numerical technique for dynamic analysis of structures with friction devices , 1995 .

[4]  L. Javier Malvar,et al.  BRIDGE RETROFIT TESTING: HINGE CABLE RESTRAINERS , 1989 .

[5]  Reginald DesRoches,et al.  EFFECT OF POUNDING AND RESTRAINERS ON SEISMIC RESPONSE OF MULTIPLE-FRAME BRIDGES , 2002 .

[6]  Jack P. Moehle,et al.  Highway Bridges and Traffic Management , 1995 .

[7]  John C. Wilson,et al.  REPAIR OF NEW LONG-SPAN BRIDGES DAMAGED BY THE 1995 KOBE EARTHQUAKE , 2003 .

[8]  Hong Hao,et al.  A parametric study of the required seating length for bridge decks during earthquake , 1998 .

[9]  Mjn Priestley,et al.  Seismic Design and Retrofit of Bridges , 1996 .

[10]  M Saiidi.  RESPONSE OF BRIDGE HINGE RESTRAINERS DURING EARTHQUAKES FIELD PERFORMANCE, ANALYSIS, AND DESIGN , 1993 .

[11]  Sang-Woo Lee,et al.  Unseating Failure of Bridge Spans under Seismic Excitations Considering Inelastic Pier and Foundation Motions , 1999 .

[12]  Raj V. Siddharthan,et al.  Stiffnesses of abutments on spread footings with cohesionless backfill , 1997 .

[13]  M. Saiid Saiidi,et al.  Effects of the Hinge Restrainers on the Response of the Aptos Creek Bridge during the 1989 Loma Prieta Earthquake , 1997 .

[14]  Mehdi Saiidi,et al.  Experimental Evaluation of Longitudinal Seismic Performance of Bridge Restrainers at In-Span Hinges , 2004 .

[15]  Emmanuel A. Maragakis,et al.  Parameters in Bridge Restrainer Design for Seismic Retrofit , 1996 .

[16]  John F. Stanton,et al.  Design of Seismic Restrainers for In-Span Hinges , 1997 .

[17]  Masanobu Shinozuka,et al.  Energy dissipating restrainers for highway bridges , 2000 .

[18]  Reginald DesRoches,et al.  Design of seismic cable hinge restrainers for bridges , 2000 .