International Journal of Structural Stability and Dynamics
Vol.9,No.1(2009)151–177
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d Scientific Publishing Company
PASSIVE RESPONSE CONTROL SYSTEMS
FOR SEISMIC RESPONSE REDUCTION:
A STATE-OF-THE-ART REVIEW
Y.M.PARULEKAR∗and G.R.REDDY
Reactor Safety Division
Bhabha Atomic Rearch Centre
Mumbai-400085,India
∗v.in
Received27November2007
Accepted18July2008
Rearch and development of ismic respon control devices has gained prime impor-
tance recently,due to an incread number of devastating earthquakes.Passive control
systems are now accepted all over the world and hence rearch in this area is continuing
to develop reliable,efficient and cost effective devices along with constitutive modeling.
This paper begins with qualitative description and comparison of passive,active and
miactive control systems.Further,it mentions advantages of passive control systems
over the others.A detailed literature review of passive devices is then provided which
includes the historical development of the devices,their dynamic behavior,testing of
the devices incorporated in the structural models and their analytical formulations.
The pros and cons of the devices in retrofitting of structures and theirfirst and recent
applications in a wide variety of structures are also discusd.The passive respon
control systems that are discusd include viscoelastic dampers,yielding dampers,vis-
cous dampers,friction dampers,tuned mass dampers,tuned liquid dampers,tuned liq-符蓉
纸糊灯笼uid column dampers,superelastic dampers,like shape memory alloy dampers and ba
isolators.
Keywords:Dampers;ismic;earthquake;respon;passive;control.
1.Introduction
The safety of public civil structures,residential buildings,lifeline structures and historical structures,as well as industrial structures,equipment and piping sys-tems,should be ensured against all natural hazards,including earthquakes.With public safety as the paramount concern,the structures should be designed to withstand the earthquake level given by the codes.1–3In the conventional ismic-resistance-bad design approach,the strength of the system and its ductility are incread to resist the earthquake loads.However,this approach has proven to be quite expensive,and hence another approach has recently been gaining wide acceptance,namely the ismic respon control design approach.
∗Corresponding author.
151
152Y.M.Parulekar&G.R.Reddy
The respon control design approach basically us passive,active and miac-tive control devices.A passive control system—e Fig.1(a)—does not require an external power supply.Such de什么是民主革命
vices respond as per the structural respon,dis-sipate the energy in the form of heat and eventually reduce the structural respon. Friction dampers,yielding elastoplastic dampers,viscous dampers etc.fall into this category.Passive devices,such as ba isolators,modify the free vibration charac-teristics of the structure and brings it to a lower frequency,where the amplitude of earthquake excitation is smaller.Some of the passive dampers are reviewed in ATC Guidelines4and EERI.5
An active control system—e Fig.1(b)—is one in which external source power control actuators require large power sources on the order of tens of kilowatts for small structures and veral megawatts for large structures.The actuators apply forces to the structure in a prescribed manner,which can be ud to both add and dissipate energy in the structure.In the active feedback control system,the signals nt to the control actuators are a function of the respon of the system measures with physical nsors.Active tuned mass dampers,active variable stiffness systems and active pul generators are some of the active dampers.An overview of active respon control has been provided by Soong et al.6
Fig.1(a)Structure with passive Fig.1(b)Structure with active control control device.device.
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Fig.1(c)Structure with miactive control device.
Passive Respon Control Systems for Seismic Respon Reduction153
A miactive control system—e Fig.1(c)—is a combination of active and passive systems.This faci
litates less supply power on the order of tens of watts input to the systems.The advantage is that in ca of power failure the passive component of the control will still offer some protection.Among the dampers of this type are mechatro dampers,variable friction dampers and controllable tuned liquid dampers.Semiactive control systems have been reviewed by Symans et al.7 Hybrid control systems consisting of combined passive and miactive devices8,9 and of combined passive and active devices10,11are described in the literature. Passive hybrid control systems,mentioned by Makris et al.12and Soneji et al.,13 consist of passive supplemental energy dissipation devices in association with ba isolation systems.
However,active and miactive devices have the main disadvantage of the u of power,and hence they are not that attractive in ismic respon control.In a vere earthquakes,power failure often occurs and the power required to operate active and miactive devices may not be available.Moreover,in many industries there are a large number of active control devices for controlling the various normal operating parameters,such as temperature and pressure.To take care of uncertainty,there is redundancy built into the control systems,which further results in increasing the number of control systems.Hence there is always a requirement to reduce the number of active systems and miactive systems,and it is usually recommended to go for passive devices and the fa
il-safe design approach.For the above reasons,it is felt to be necessary to carry out a wide-ranging literature review of passive dampers and mention the advantages and limitations of each along with their applications in real life structures.
In1996,the US Panel on Structural Control Rearch14carried out a survey of structural control and its applications.It provided good background on structural control.In the prent paper recent developments in passive respon control and some of the applications of passive devices in structures in Japan are also covered.
线描画树2.State-of-the-Art Review of Passive Control Systems
Passive control systems may be grouped into three types:energy dissipaters,tuned dampers and ba isolators.Energy dissipaters increa the energy dissipation capa-bility of the structure to which they are attached by conversion of mechanical energy into heat energy.Dampers working on this principle are viscoelastic dampers,yield-ing dampers,viscous dampers and friction dampers.Tuned dampers work on the principle of transfer of energy to the damper among the vibrating modes.Examples of the dampers are tuned mass dampers and tuned liquid dampers.Ba isolation devices attenuate the horizontal earthquake ba acceleration transmitted to the superstruc
ture by modifying the free vibration characteristics of the structure and bringing it to a lower frequency,where the amplitude of the earthquake excitation is smaller.Ba isolation shifts the fundamental period of the structure out of the range of the dominant earthquake energy and also increas the energy-absorbing
154Y.M.Parulekar&G.R.Reddy
capability of the structure.Laminated rubber bearings,laminated rubber bearings with lead core and friction pendulum systems are some of the ba isolators.
Some of the common passive control systems,which are implemented in actual practice,are described in detail henceforth.
2.1.Viscoelastic dampers
The concept of viscoelastic dampers(VEDs)was prented way back in1969by Mahmoodi,15who carried out extensive analytical and experimental investigations to study the performance of viscoelastic devices as energy dissipaters for structural applications.The damper shown in Fig.2compris two viscoelastic layers bonded between three parallel rigid surfaces.The viscoelastic
material undergoes virtually pure shear deformation,and mechanical energy is converted to heat.The force–displacement characteristics of the damper are shown in Fig.2(b).One of the early applications of such dampers in appeared in the1970s;it was for controlling wind vibrations in the twin towers of the World Trade Center in New York.16Gerb17 ud the helical springs and the accompanying VEDs in1978for energy dissipation purpos under machine foundations.
In1989,Zhang18carried out experimental and analytical studies and showed that VEDs are effective in reducing the ismic respon of steel structures.In 1992,Zhang and Soong19studied the number,size and optimal location of VEDs for supporting the structure and their effects on the stiffness and damping ratio. They inferred that VEDs attached to a structure increa viscous damping as well as the lateral stiffness of the structure.Viscoelastic materials are copolymers or glassy materials.19The effect of ambient temperature on viscoelastically damped structure was studied by Chang et al.20in1992.Tho authors showed that the efficiency of the dampers is dependent on the excitation frequency and the ambient temperature at which they operate.As the temperature is incread,there is a pro-portional decrea in energy dissipation.The authors also accurately predicted the ismic respon of structures with VEDs,at various temperatures,using equivalent
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Steel plate
Fig.2(a)Viscoelastic(VE)damper.
viscoelastic damper.
Passive Respon Control Systems for Seismic Respon Reduction155 damping by the strain energy method.In1993,Tsai21propod analytical models of VEDs using the fractional derivative approach.However,the constants ud in this model lacked physical meaning.Later,Shen and Soong22prented a consis-tent model bad on the Boltzman superposition principle.A full scale vibration test of VEDs was performed by Lai et al.23in1995.The damper design procedure was developed from the model and could be readily applied to full scale structure by scaling up the size of the VE material in the dampers.Seismic applications of VEDs include the13-storey steel moment frame building in Santa Clara county in1994,the Chiba city gymnasium building in Japan199424and the City Hall of San Francisco in1997.25In Japan,Shimizu Corp.developed viscoelastic walls in which solid thermoplastic rubber sheets are sandwiched between steel plates.26In 2003,Lin and Chopra27investigated earthquake respons of one-storey systems with VEDs attached toflexible braces andfluid viscous dampers attached to rigid chevron braces.They showed that asymmetric systems with the dampers can be estimated with sufficient accuracy for design applications by analyzing the same system replaced by energy-equivalent linear viscous dampers.
2.2.Metallic yield dampers
Metallic yield dampers utilize the inelastic deformation of metals in dissipating the energy prent in t
he vibration of a structure during an earthquake.The idea of using metallic energy dissipators in earthquake design was introduced by Kelly and Skinner28in1972.In the tests conducted it was shown that the plastic torsion of mild steel is an extremely efficient mechanism for the absorption of energy.Sub-quently,in early the1990s,X-shaped devices using mild steel—called added stiff-ness damping devices(ADAS)—and triangular plates(TADAS)were propod by Whittaker et al.29and Tsai et al.30The X shape was chon for the devices so that the strain in them would remain constant over their height.In Japan,Y-shaped brace dampers were ud as energy absorbers by various Japane construction companies.31
The dampers could also be applied to piping systems and were identified as elastoplastic type piping supports.One of thefirst piping system vibration test using the elastoplastic type piping support devices was conducted in1983by Schneider et al.at EPRI.32Later,snubbers in nuclear power plant pipings in Japan were propod to be replaced by elastoplastic(yielding)dampers,following the tests on piping systems made by Namita et al.in1990.33The yielding type energy absorber, which can be directly applied to the piping system,is shown in Fig.3(a),and its hysteresis characteristics are shown in Fig.3(b).
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One of thefirst applications of metallic yield dampers to structures was in New Zealand in the1980s.3
4In1983,the12-storey Union Hou35in Auckland was isolated using laterallyflexible piles with moment-resisting pins at each end, and steel tapered cantilever dampers were attached to the top of the piles to pro-vide energy dissipation and deflection control.The dampers were also placed in
