Experimental study of sliding base-isolated buildings with magnetorheological dampers in near-fault earthquakes

The increase in bearing displacements of sliding isolated buildings due to near-fault earthquakes, with long-period pulse type of ground motion, is an important problem. Often, supplemental nonlinear passive dampers are incorporated into the isolation system to reduce the base displacements; however, this may increase the interstory drifts and accelerations in the superstructure. Hence, there is a need to examine whether controllable nonlinear dampers can reduce the base displacements without a further increase in superstructure response. In this study, the effectiveness of variable damping, provided by magnetorheological (MR) dampers, in reducing the response of sliding isolated buildings during near-fault earthquakes is investigated using a 1:5 scale steel two-story model. A nonlinear analytical model is developed with due consideration given to the nonlinearities of the friction bearings and the MR damper. A Lyapunov-based control algorithm is developed for control of the MR damper and the building model, and tested on a shake table. Results of passive low/high damping cases and semiactive cases are compared. It is shown that the variable damping reduces base displacements and superstructure responses further than passive low/high damping cases.

[1]  Satish Nagarajaiah,et al.  Base-Isolated FCC Building: Impact Response in Northridge Earthquake , 2001 .

[2]  Michael D. Symans,et al.  Analytical and Numerical Study of a Smart Sliding Base Isolation System for Seismic Protection of Buildings , 2003 .

[3]  B. F. Spencer,et al.  STATE OF THE ART OF STRUCTURAL CONTROL , 2003 .

[4]  Yunfeng Zhang,et al.  PROTECTING BASE-ISOLATED STRUCTURES FROM NEAR-FIELD GROUND MOTION BY TUNED INTERACTION DAMPER , 2002 .

[5]  Shih-Po Chang,et al.  Effect of viscous, viscoplastic and friction damping on the response of seismic isolated structures , 2000 .

[6]  Satish Nagarajaiah,et al.  Response of Base-Isolated USC Hospital Building in Northridge Earthquake , 2000 .

[7]  Nicos Makris,et al.  RIGIDITY–PLASTICITY–VISCOSITY: CAN ELECTRORHEOLOGICAL DAMPERS PROTECT BASE‐ISOLATED STRUCTURES FROM NEAR‐SOURCE GROUND MOTIONS? , 1997 .

[8]  Farzad Naeim,et al.  Design of seismic isolated structures , 1999 .

[9]  James M. Kelly,et al.  Earthquake-Resistant Design with Rubber , 1993 .

[10]  Henri P. Gavin,et al.  FAULT TOLERANCE OF SEMIACTIVE SEISMIC ISOLATION , 2003 .

[11]  Michael C. Constantinou,et al.  Semi-active control systems for seismic protection of structures: a state-of-the-art review , 1999 .

[12]  Satish Nagarajaiah,et al.  A STFT semiactive controller for base isolated buildings with variable stiffness isolation systems , 2005 .

[13]  James M. Kelly,et al.  The role of damping in seismic isolation , 1999 .

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

[15]  Billie F. Spencer,et al.  “Smart” Base Isolation Strategies Employing Magnetorheological Dampers , 2002 .

[16]  Takuji Kobori,et al.  Actual seismic response controlled building with semi-active damper system , 1999 .

[17]  R. S. Mills,et al.  Model tests on earthquake simulators: Development and implementation of experimental procedures , 1979 .

[18]  Shirley J. Dyke,et al.  Benchmark problems in structural control: part I—Active Mass Driver system , 1998 .

[19]  Michael C. Constantinou,et al.  3D-BASIS - Nonlinear Dynamic Analysis of Three-Dimensional Base Isolated Structures: Part II , 1991 .

[20]  Shirley J. Dyke,et al.  PHENOMENOLOGICAL MODEL FOR MAGNETORHEOLOGICAL DAMPERS , 1997 .

[21]  Satish Nagarajaiah,et al.  Control of Sliding‐Isolated Bridge with Absolute Acceleration Feedback , 1993 .

[22]  David A. Robb,et al.  MAGNETORHEOLOGICAL FLUID DAMPERS FOR ROTOR VIBRATION CONTROL , 2001 .

[23]  Satish Nagarajaiah,et al.  Semi‐active control of sliding isolated bridges using MR dampers: an experimental and numerical study , 2005 .

[24]  Erik A. Johnson,et al.  "SMART" BASE ISOLATION SYSTEMS , 2000 .

[25]  Marvin W. Halling,et al.  Near-Source Ground Motion and its Effects on Flexible Buildings , 1995 .

[26]  John F. Hall,et al.  The role of damping in seismic isolation , 1999 .

[27]  Michael D. Symans,et al.  Experimental Verification of Seismic Response of Building Frame with Adaptive Sliding Base-Isolation System , 2002 .

[28]  Sanjay Suhas Sahasrabudhe,et al.  Semi-active control of sliding isolated buildings and bridges with variable stiffness and damping systems , 2002 .

[29]  Anil K. Agrawal,et al.  Semi-active hybrid control systems for nonlinear buildings against near-field earthquakes , 2002 .

[30]  Roger P. Young,et al.  Seismic isolation design of the San Bernardino County Medical Center replacement project , 1996 .

[31]  Michael D. Symans,et al.  Fuzzy logic control of bridge structures using intelligent semi‐active seismic isolation systems , 1999 .

[32]  Henri P. Gavin,et al.  Control of seismically excited vibration using electrorheological materials and Lyapunov methods , 2001, IEEE Trans. Control. Syst. Technol..

[33]  Michael D. Symans,et al.  Analytical and numerical study of a smart sliding base isolation system for seismic protection of buildings , 2000, Smart Structures.

[34]  Y. Wen.  Method for Random Vibration of Hysteretic Systems , 1976 .