PASSIVE RESPONSE CONTROL SYSTEMS FOR ...

February 3, 2009 15:36 WSPC/165-IJSSD

00296

International Journal of Structural Stability and Dynamics Vol. 9, No. 1 (2009) 151–177 c World 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 Research Centre Mumbai-400085, India ∗ [email protected] Received 27 November 2007 Accepted 18 July 2008 Research and development of seismic response control devices has gained prime importance recently, due to an increased number of devastating earthquakes. Passive control systems are now accepted all over the world and hence research 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 semiactive 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 these devices incorporated in the structural models and their analytical formulations. The pros and cons of these devices in retrofitting of structures and their first and recent applications in a wide variety of structures are also discussed. The passive response control systems that are discussed include viscoelastic dampers, yielding dampers, viscous dampers, friction dampers, tuned mass dampers, tuned liquid dampers, tuned liquid column dampers, superelastic dampers, like shape memory alloy dampers and base isolators. Keywords: Dampers; seismic; earthquake; response; 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 systems, should be ensured against all natural hazards, including earthquakes. With public safety as the paramount concern, these structures should be designed to withstand the earthquake level given by the codes.1–3 In the conventional seismicresistance-based design approach, the strength of the system and its ductility are increased 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 seismic response control design approach. ∗Corresponding

author. 151


152

00296

Y. M. Parulekar & G. R. Reddy

The response control design approach basically uses passive, active and semiactive control devices. A passive control system — see Fig. 1(a) — does not require an external power supply. Such devices respond as per the structural response, dissipate the energy in the form of heat and eventually reduce the structural response. Friction dampers, yielding elastoplastic dampers, viscous dampers etc. fall into this category. Passive devices, such as base isolators, modify the free vibration characteristics 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 Guidelines4 and EERI.5 An active control system — see 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 several megawatts for large structures. These actuators apply forces to the structure in a prescribed manner, which can be used to both add and dissipate energy in the structure. In the active feedback control system, the signals sent to the control actuators are a function of the response of the system measures with physical sensors. Active tuned mass dampers, active variable stiffness systems and active pulse generators are some of the active dampers. An overview of active response control has been provided by Soong et al.6

Through controller

Heat Energy dissipaters

sensors

High Power source (10 kW- MW)

Actuators

Through controller

sensors

Reaction Input excitation

Structure

Reduced Response

Fig. 1(a) Structure with passive control device.

Through controller sensors

Heat Input excitation

Input excitation

Structure

Response

Fig. 1(b) Structure with active control device.

Low Power Through Source (10 W) controller Actuators

sensors

Energy dissipaters

Structure

Response

Fig. 1(c) Structure with semiactive control device.


00296

Passive Response Control Systems for Seismic Response Reduction

153

A semiactive control system — see Fig. 1(c) — is a combination of active and passive systems. This facilitates less supply power on the order of tens of watts input to the systems. The advantage is that in case 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 semiactive devices8,9 and of combined passive and active devices10,11 are described in the literature. Passive hybrid control systems, mentioned by Makris et al.12 and Soneji et al.,13 consist of passive supplemental energy dissipation devices in association with base isolation systems. However, active and semiactive devices have the main disadvantage of the use of power, and hence they are not that attractive in seismic response control. In a severe earthquakes, power failure often occurs and the power required to operate active and semiactive 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 semiactive systems, and it is usually recommended to go for passive devices and the fail-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. In 1996, the US Panel on Structural Control Research14 carried out a survey of structural control and its applications. It provided good background on structural control. In the present paper recent developments in passive response control and some of the applications of passive devices in structures in Japan are also covered. 2. State-of-the-Art Review of Passive Control Systems Passive control systems may be grouped into three types: energy dissipaters, tuned dampers and base isolators. Energy dissipaters increase the energy dissipation capability of the structure to which they are attached by conversion of mechanical energy into heat energy. Dampers working on this principle are viscoelastic dampers, yielding 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 these dampers are tuned mass dampers and tuned liquid dampers. Base isolation devices attenuate the horizontal earthquake base acceleration transmitted to the superstructure 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. Base isolation shifts the fundamental period of the structure out of the range of the dominant earthquake energy and also increases the energy-absorbing


154

00296


capability of the structure. Laminated rubber bearings, laminated rubber bearings with lead core and friction pendulum systems are some of the base 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 presented way back in 1969 by Mahmoodi,15 who 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. 2 comprises 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 the 1970s; it was for controlling wind vibrations in the twin towers of the World Trade Center in New York.16 Gerb17 used the helical springs and the accompanying VEDs in 1978 for energy dissipation purposes under machine foundations. In 1989, Zhang18 carried out experimental and analytical studies and showed that VEDs are effective in reducing the seismic response of steel structures. In 1992, Zhang and Soong19 studied 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 increase viscous damping as well as the lateral stiffness of the structure. Viscoelastic materials are copolymers or glassy materials.19 The effect of ambient temperature on viscoelastically damped structure was studied by Chang et al.20 in 1992. Those 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 increased, there is a proportional decrease in energy dissipation. The authors also accurately predicted the seismic response of structures with VEDs, at various temperatures, using equivalent

F/2

Force

F/2

Steel plate

V.E. Material

Displ.

Centre plate

F Fig. 2(a) Viscoelastic (VE) damper.

Fig. 2(b) Typical hysteresis loop of a viscoelastic damper.


00296


155

damping by the strain energy method. In 1993, Tsai21 proposed analytical models of VEDs using the fractional derivative approach. However, the constants used in this model lacked physical meaning. Later, Shen and Soong22 presented a consistent model based on the Boltzman superposition principle. A full scale vibration test of VEDs was performed by Lai et al.23 in 1995. 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 the 13-storey steel moment frame building in Santa Clara county in 1994, the Chiba city gymnasium building in Japan 199424 and the City Hall of San Francisco in 1997.25 In Japan, Shimizu Corp. developed viscoelastic walls in which solid thermoplastic rubber sheets are sandwiched between steel plates.26 In 2003, Lin and Chopra27 investigated earthquake responses of one-storey systems with VEDs attached to flexible braces and fluid viscous dampers attached to rigid chevron braces. They showed that asymmetric systems with these 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 present in the vibration of a structure during an earthquake. The idea of using metallic energy dissipators in earthquake design was introduced by Kelly and Skinner28 in 1972. In the tests conducted it was shown that the plastic torsion of mild steel is an extremely efficient mechanism for the absorption of energy. Subsequently, in early the 1990s, X-shaped devices using mild steel — called added stiffness damping devices (ADAS) — and triangular plates (TADAS) were proposed by Whittaker et al.29 and Tsai et al.30 The X shape was chosen for the devices so that the strain in them would remain constant over their height. In Japan, Y-shaped brace dampers were used as energy absorbers by various Japanese construction companies.31 These dampers could also be applied to piping systems and were identified as elastoplastic type piping supports. One of the first piping system vibration test using the elastoplastic type piping support devices was conducted in 1983 by Schneider et al. at EPRI.32 Later, snubbers in nuclear power plant pipings in Japan were proposed to be replaced by elastoplastic (yielding) dampers, following the tests on piping systems made by Namita et al. in 1990.33 The 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). One of the first applications of metallic yield dampers to structures was in New Zealand in the 1980s.34 In 1983, the 12-storey Union House35 in Auckland was isolated using laterally flexible piles with moment-resisting pins at each end, and steel tapered cantilever dampers were attached to the top of the piles to provide energy dissipation and deflection control. These dampers were also placed in


156

00296


Force

bridges, among which the 70-m-tall South Rangitikei Viaduct in New Zealand36 was isolated through controlled base uplift and transverse rocking action. The lateral movement of the bridge deck was limited by energy dissipation provided by torsionally yielding steel beam devices. Subsequently, many structures were seismically isolated using yielding dampers, in Japan.26 The first application of metallic (ADAS) dampers in the US was for the seismic upgrade of a building in San Francisco,37 which suffered structural damage during the 1989 Loma Prieta Earthquake. Thereafter, research was in the field of developing analytical models and simplified analysis procedures. In 1995, Tsai38 developed a mathematical model using finite element formulation based on plasticity theory, for triangular (tapered) plate energy absorbers, and there was good agreement between experimental and numerical results. The analytical model of the force–displacement relationship of the X plate is obtained from dimensions of the plate using beam theory33 and compared with test results. Nonlinear dynamic analysis needs to be carried out for the structure with metallic dampers subjected to earthquake ground motion. Scholl in 199339 proposed an alternative approach based on equivalent viscous damping; using it, linear analysis with increased damping due to metallic dampers gives a reasonably accurate response. In 2003, the earthquake behavior of structures with X-shaped copper energy dissipaters was studied,40 copper being ductile, having a low yield, and being highly resistant to corrosion. In 2003, Phocas and Pocanschi41 implemented a mechanism in frame structures which consisted of a cross-bracing mechanism, and the increase in the length of a cross-cable diagonal was equal to the same length decrease of the other cross-cable diagonal, so that under cyclic loading both cross-braces were permanently under tension. A hysteretic damper, connected between the frame and the horizontal cable member of the bracing mechanism, yielded during strong ground motions and allowed for relative motion between the bracing and the frame. In 2006, Parulekar et al.42 compared the experimental and

Displacement

X shaped plates

Connecting lug X-Plate

Fig. 3(a) Metallic yield damper.

Fig. 3(b) Force–displacement hysteretic relation.


00296

Passive Response Control Systems for Seismic Response Reduction 60

δ Test with EPD δ TH Analysis with EPD

Displacement (mm)

50

3” NB Sch 40 pipe of length 1.6 m. 305 kg

157

δ Test without EPD δ TH Analysis without EPD

40 30 20 10 0 0.0

EPD

0.2

0.4

0.6

0.8

1.0

Maximum acceleration in g Fig. 3(c) Cantilever piping system.

Fig. 3(d) Comparison of the displacement for the cantilever piping system.

Sup.Accn

0.15

Accling

0.10 0.05 0.00 -0.05 -0.10 -0.15 0

2

4

6

8

10

12

14

16

18

20

Time (secs)

Fig. 3(e). Support input acceleration time history.

the analytical response of piping systems with yielding X plate dampers and proved that a simplified procedure like the iterative response spectrum technique43 using Caughey equivalent damping gives a reasonably acceptable response of the piping systems supported on yielding dampers, as shown in Fig. 4(b). Recently, in 2007, a simplified seismic design procedure for steel bridge piers to be fitted with hysteretic damping devices was proposed by Chen et al.,44 using equivalent single-degreeof-freedom methodology and inelastic response spectra. Optimum parameters of X plate dampers for seismic response control of piping systems were obtained by Bakre et al.45 An SDOF cantilever piping system, shown in Fig. 3(c), is tested on a shake table42 and subjected to support input acceleration time history, as shown in Fig. 3(e). Time history analysis is performed on the piping system (3% damping) for 0.15 g, 0.45 g and 0.9 g peak acceleration with and without 3-mm-thick, X plate EPD. Figure 3(d) shows that analysis provides a good estimate of the test results and there is a 40% reduction in the response of the piping system, with less than a 10% shift in its natural frequency.


158

00296


One of the recent seismic applications of hysteretic dampers24 is a 120-m-tall office building in Saitama, Japan, which has shear walls made of low yield point steel (having a yield point 1/3 of mild steel and a large elongation capacity) working as hysteretic dampers. Metallic dampers like lead extrusion dampers,46 based on the extrusion principle, were designed by Robinson and Greenbank in 1976. They are designed such that they require a large force to yield and are generally used in footings of structures or to control the response of large equipment. A schematic diagram of a lead extrusion damper (LED) is shown in Fig. 4(a). Reduction of the seismic response of a coolant channel assembly of nuclear power plants when the fueling machines are supported on LEDs was shown by Parulekar et al.47 A two-degree-of-freedom system which consists of two linear springs connected by masses of 15 tons each, representing equipment, is shown in Fig. 4(b). Time history analysis is carried out for the system with 2% damping with the input time history having a peak acceleration of 0.5 g. The relative displacement time history of spring 2 is shown in Fig. 4(c). The masses are attached with LEDs (capacity of 15 tons each) on either side, as shown in Fig. 4(d). The system is analyzed for the same time history, and the time history response of spring 2 for the system with dampers is shown in Fig. 4(e), while force–displacement diagrams of LEDs are shown in Fig. 4(f). It is observed from the figures that LEDs dissipate a large amount of energy and thus effectively reduce the response of spring 2 due to earthquake motion. Bulged-shaft Bearing

Cylindrical tube

Lead M1 = 15 T

Kspr2=

Kspr1=

2.72 X 10 8 N/m

Displacements (m)

Fig. 4(a) Lead extrusion damper.

0.03 spring 2 0.02 0.01 0.00 -0.01 -0.02 -0.03 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (Secs)

M2 = 15 T

2.32 X10 7 N/m

Fig. 4(b) Two-degree-of-freedom system without LEDs.

Kspr1 KLED1,KLED2= Stiffnesses of LEDs

M1 KLED1

M2 Kspr2

Fig. 4(c) Response of spring 2 for the system

Fig. 4(d) Two-degree-of-freedom

without dampers.

system with LEDs.

KLED2


00296

Displacement (m)


0.004 0.002 0.000 -0.002 -0.004 -0.006

159

Spring 2

0 2 4 6 8 1012 14 16 18 20 22 24 26 Time (secs)

1.5x105 1.0x105 5.0x104 0.0 -5.0x104 -1.0x105 -1.5x105 -0.004 -0.002 0.000 0.002 Displacement (m)

Force (N)

Force (N)

Fig. 4(e) Response of spring 2 for the system with dampers.

LED1

0.004

1.5x105 1.0x105 5.0x104 0.0 -5.0x104 -1.0x105 LED2 -1.5x105 -0.0050 -0.0025 0.0000 0.0025 0.0050 Displacement (m)

Fig. 4(f) Force–displacement loops of LEDs when subjected to earthquake loads.

Maximum applications of LEDs have been made in New Zealand and Japan. In the 1980s in New Zealand (Wellington), the Aurora Terrace bridge, a sloping bridge, was fitted with these dampers at a lower abutment. LEDs lock the bridge in place during the braking of vehicles traveling downhill, at earthquake loads they allow the bridge to move, and also they allow the thermal expansion load by creep of extrusion dampers.48 Another application of LEDs was at the Wellington central police station,49 where these dampers were connected between the top of the piles and the structurally separate embedded basement. New materials like shape memory alloys (SMAs), which have the pseudoelastic property by which the alloy recovers its initial shape on the removal of the external load, are being developed. Such materials were first studied by Graesser and Cozorelli50 in 1991. SMAs (nickel–titanium alloys) also have high resistance to large strain cycle fatigue, great durability and exceptional corrosion resistance.51 Dolce et al.52 in 2000 developed SMA devices based on wires and showed that they have a good energy-absorbing capability and the important additional property of recentering. The SMA device based on wires is shown in Fig. 5(a), in which, during cyclic loading, three sets of wires will be in tension and another three in slack. The wires which are in tension will dissipate energy; the hysteresis loop of wire subjected to a cyclic load in tension is shown in Fig. 5(b). A cantilever piping system, shown in Fig. 3(c), is subjected to high level input acceleration of a 1.2 g peak with the time history shown in Fig. 3(e). Time history analysis of the piping system is carried out; the response of the piping system is shown in Fig. 5(c). The piping system is then supported on an SMA damper; the response of the piping with damper is shown in Fig. 5(d). It can be observed that there is no permanent deformation in the



Force

160

00296

Inner Cylinder

6 SMA Wires

Deformation Fig. 5(a) Shape memory alloy damper.

80

Fig. 5(b) Hysteresis loop of SMA wire subjected to a cyclic tensile load.

P ip e w ith o u t d a m p e r

Tip Displacement (mm)

60 40 20 0 -2 0 -4 0 -6 0 -8 0 0

2

4

6

8

1 0 12 14 1 6 18 2 0 22

T im e (S ecs)

Fig. 5(c) Displacement response of a cantilever pipe without damper for 1.2 g peak acceleration.

50

Pipe with SMAD

60

Load in Damper (kg)

Displacement (mm)

80 40 20 0 -20 -40 -60 -80

0

5

10 15 Time (secs)

20

25 0 -25 -50 -80 -60 -40 -20 0 20 40 60 80 Displacement (mm)

Fig. 5(d) Displacement response of a pipe with SMAD for 1.2 g peak acceleration.


00296


161

piping system when the SMA damper is connected to it. Moreover, there is a 40% reduction in the response of the piping system. Thus, the recentering capability of the SMA damper is an attractive property for eliminating permanent deformation of structures, equipment and piping systems. Sreekala et al.53 performed a number of cyclic tests on this damper and it showed a good energy-absorbing capability. 2.3. Tuned mass dampers The concept of the tuned mass damper (TMD) was introduced by Frahm54 in 1909. Later, in the 1940s, Hartog55 proposed an optimal design theory of the TMD for an undamped SDOF system subjected to harmonic excitation. This device is a dynamic vibration absorber consisting of an auxiliary mass on the order of 1% of the mass of the structure, tuned to the frequency of the structure by connecting it through a passive spring. This mass, as shown in Fig. 6, is generally located at the top of the building. The TMD’s initial application was to control the displacement response of the structures subjected to wind-induced vibrations. McNamara56 first studied it in 1977, and then Luft57 in 1979. Some of the first few applications of TMDs for suppressing wind-induced vibrations are the Centre Point Tower (305 m tall) in Sydney, the Citicorp center (274 m tall) in New York and the Chiba port tower in Japan (in 1986); while the recent applications to suppress wind-induced vibrations are the CN tower (535 m tall) in Canada and the Taipei 101 tower (501 m tall) in Taiwan. Warburton58 in 1982 extended the solution of TMDs for other cases of excitations. However, their use in controlling the seismic response of structures was initially not very convincing.58,59 Sladek and Klinger60 in 1983 investigated the performance of TMDs on tall buildings subjected to seismic loading and concluded that the dampers are not effective in reducing the maximum response in tall buildings. This is due to the fact that earthquake ground motions include a wide spectrum of frequency components and often induce significant vibration in the fundamental and higher modes of a tall building. The first mode response of a structure with TMDs tuned to the

Tuned Mass Damper

Fig. 6 Tuned mass damper attached to an SDOF frame.


162

00296


fundamental frequency can be substantially reduced, but higher mode responses may only be marginally reduced. A single damper tuned to the fundamental frequency of the structure is thus unable to suppress the vibration of higher modes. Hence, Clark61 in 1988 introduced multiple tuned mass dampers (MTMDs), which are tuned to different modes and placed at various locations to enhance the seismic performance of the dampers. In 1995, Kareem62 and Jangid63 showed that MTMDs with the optimal frequency range are more robust and effective than single TMDs. By selecting a frequency range for the MTMDs, an error in estimation of the primary system frequency or changes in the stiffness of the structure under loads can be eliminated. In 1997, Jangid and Dutta64 studied the response control of a twodegree-of-freedom irregular torsional system to a white noise excitation by a cluster of MTMDs. In 2000, Lin et al.65 studied a multistoried torsional building with one and two TMDs. The optimum parameters were obtained through minimization of the root-mean-square displacement response of the dominant mode. In 2000, Wu and Chen66 studied an MTMD system divided into several groups, with each group corresponding to one mode and consisting of several oscillators. In 2002, Li67 obtained optimum parameters of MTMDs like frequency spacing, average damping ratio, tuning frequency ratio, mass ratio and total number of MTMDs. These were obtained by the criteria based on maximum displacement and acceleration magnification factor minimization. In 2006, a numerical iterative method for searching for the optimal design parameters of MTMDs in a systematic fashion were used by researchers.68,69 Though a lot of research has been carried out on structures with MTMDs subjected to earthquake loads, maximum applications of TMDs have been made only for wind vibrations. However, implementation of active mass dampers to cater for earthquake loads has been done for the 11-storey Kyobashi Seiwa Building in Tokyo (in 1989).70 2.4. Tuned liquid dampers Tuned liquid dampers (TLDs) are energy-absorbing devices that control the dynamic response of structures using the sloshing resonance of liquid in a shallow tank. A TLD is essentially a rigid tank with shallow water having a mass on the order of 1% of the mass of the structure connected rigidly to a structure, as shown in Fig. 7(a). Tuning the fundamental sloshing frequency of the TLD to the structure’s natural frequency causes a large amount of sloshing at the resonant frequencies of the combined TLD–structure system. It absorbs a significant amount of energy. However, TLDs are generally used to control vibrations of high-rise structures, as the natural frequencies of these flexible structures (with a frequency of less than 2 Hz) are close to the oscillation frequency of the shallow liquid. The linear equivalent TMD model through an integration of the simplified linear theory is able to match the main dynamic properties of the TLD at a low excitation level. But this approximation worsens with an increasing excitation level. Since the linear model is developed on the basis of force interaction, it fails to capture the


00296


163

underlying phenomenon of nonlinearity. Welt and Modi71 in 1987 initially proposed a TLD for reducing the response of structures due to a dynamic load. They conducted an experimental and analytical study72,73 on a mutation damper (annular tank), which is conceptually the same as the TLD. Their theoretical investigation concerned the energy dissipation mechanism assuming a potential flow with a nonlinear free surface condition in conjunction with boundary layer correction. Fujino et al.74 in 1988 carried out experimental studies on the cylindrical liquid dampers. In 1992, Fujino et al.75 developed a two-dimensional model of liquid motion in a rectangular TLD using the shallow water wave theory. They solved a system of continuity and equilibrium equations for an incompressible and irrotational fluid. Sun et al.76 proposed an analytical model for the TLD with optimal characteristics suppressing pitching motion of structures. Sun et al.77 in 1995 also presented the properties of the TLD using a TMD analogy for a small amplitude. However, this approximation worsened with an increasing excitation level. In 1999, Yu78 proposed the nonlinear stiffness-damping model, which was built on the cyclic energy dissipation and was found to be more rigorous. At a high level of excitation this model provided a good look at the nonlinear wave-breaking effect. TLDs were applied to control wind-induced vibrations of tall structures and were preferred to TMDs for several reasons, such as effectiveness for small amplitude vibrations (e.g. wind-induced instabilities), easy tuning to the natural frequency of the structure, low cost, easy installation, effectiveness for bidirectional excitation, and minimal maintenance requirements due to the absence of moving parts. Early applications of TLDS in the 1990s in Japan include the Nagasaki Airport Tower,79 the 77.6-m-tall Tokyo International Airport Tower80 and the 100-m-tall Yokohama Marine Tower.81 TLDs have generally been applied to control wind-induced vibrations of structures; however, applications have not so far been made to control seismic vibrations. In 2000, some investigations of seismic response control of structures were made by Banerji et al.82 Numerical studies were carried out with varying depth ratio for frequencies of structures between 0.5 Hz and 2 Hz under seismic excitation of up

Fig. 7(a) Tuned liquid dampers attached to the top of a two-storey frame.

Fig. 7(b) Tuned liquid column dampers attached to the top of a two-storey frame.


164

00296

Y. M. Parulekar & G. R. Reddy 0.70 0.65

Analytical Experimental

0.60 0.55 0.50

Effectiveness=ratio of decrease in response with TLD and response without TLD

Effectiveness

0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 0.00

0.01

0.02

0.03

0.04

0.05

0.06

Aspect ratio

Fig. 7(c) Shake table test on a structure with TLD.

Fig. 7(d) Effectiveness of the TLD with the aspect ratio.

to a 0.3 g peak. They mentioned that for earthquake motions it is beneficial to use large water depths of up to 0.3 within the constraints of the shallow water theory. In 2006, Savyanavar et al.83 conducted shake table tests on a structural frame with TLDs attached to the top of the frame. A study of the behavior of the threestorey frame with cylindrical liquid dampers — shown in Fig. 7(c) — under sinusoidal excitations of varying amplitudes was carried out. An equivalent linear TMD model was adopted for the analysis of the dampers. The typical wave-breaking phenomenon caused change in the behavior of the TLDs with the amplitude of excitation. Hence the linear TMD model was subsequently modified to take into account this change. The effectiveness of the dampers is plotted, as shown in Fig. 7(d) as a function of the nondimensional amplitude called the aspect ratio (Λ), which is the ratio of the amplitude of vibration and length of the tanks. It is observed that as the amplitude of excitation increases, the effectiveness of the TLD decreases, and the decrease in the effectiveness is more pronounced in the strong wave-breaking region. The dampers were effective in attenuating the earthquake response of RCC structure, having a predominant first mode for lower excitation levels. In 2007, Lee et al.84 conducted a real time hybrid shake table test for evaluating the performance of TLDs in seismic response control of structures. He studied the seismic responses of four earthquakes and observed that the acceleration was reduced by 30% at the peak due to TLDs. The tuned liquid column damper (TLCD), shown in Fig. 7(b), is an alternative to the TLD and dissipates energy by water flow between two water columns through an orifice. It was proposed by Sakai85 in 1989. Later it was applied to the Higashi– Kobe cable-stayed bridge in Japan, with TLCD units attached to the bridge deck86 to control wind vibrations. Kareem in 199487 demonstrated that TLCDs can be used to dissipate energy in two directions simultaneously by using a bidirectional U tube. In 1996, Won et al.88 evaluated the performance of TLCDs for seismic


00296


165

loading and observed that TLCDs are more promising for structures having periods higher than 2 s. Sadek et al.89 in 1998 obtained the design parameters for singletuned liquid column dampers (STLCDs) and robust multiple-tuned liquid column dampers (MTLCDs) from a deterministic response analysis of SDOF structures for 72 earthquake accelerograms. They showed that selecting optimum parameters resulted in a 47% reduction of the seismic response of structures. Later, in 2002, Shum90 showed that the performance of MTLCDs is better than that of STLCDs with the same volume of water in reducing torsional vibrations of structures. 2.5. Friction dampers The earthquake energy can be very effectively dissipated by the mechanism of friction and hence in the late 1970s Pall91 adopted the principle of the friction brake used in automobiles and developed friction dampers. Pall friction dampers consist of steel plates specially treated to develop the most reliable friction and clamped together with high strength steel bolts, as shown in Fig. 8(a). During severe seismic excitations, friction dampers slip at a predetermined optimum load, before yielding occurs in other structural members, and dissipate a major portion of the seismic energy. Pall and Marsh in 198292 developed X-braced friction dampers used for framed structures. Filiatrault and Cherry93 in 1987 refined Pall’s device using brake lining pads at the intersection of cross braces to improve its physical properties. In the late 1980s, Sumitomo Metal Industries introduced the Sumitomo friction damper for shock absorption in railway trains. This is a cylindrical device — shown in Fig. 8(b) — consisting of copper alloy lining pads with pieces of graphite impregnated, sliding against the inner surface of the metallic barrel. Aiken and Kelly94 in 1990 found that such dampers provided good performance in resisting the earthquake load along the axis of the device. Nims95 in 1993 developed an energy-dissipating restraint as a friction damper having the slip load proportional to the displacement. A typical force-displacement characteristic of the friction damper is shown in Fig. 8(c). Though these devices are inexpensive and their behavior is not affected by the frequency, the loading amplitude and the number of cycles, the slip force for these passive devices should be properly chosen so as to give the optimum energy dissipation. Moreover, the stick-slip phenomenon Friction pads (copper alloy)

Slip Joint with Friction Pads

Fig. 8(a) Friction damper (Pall).

wedge Cup spring

Outer cylinder

Fig. 8(b) Friction damper (Sumitomo).


166

00296


Friction Maximum force= µN Force F

Sliding Displacement

Minimum force=- µN Fig. 8(c) Force–displacement characteristics of a friction damper.

Fig. 8(d) Friction damper attached to a piping system.

of the plates must be minimized. Hence, compatible materials like steel or brass on high chromium content steel, and also graphite-impregnated bronze on stainless steel, should be employed to maintain a consistent frictional coefficient. One of the first applications of Pall friction dampers was to retrofit (in 1987) the Concordia University Library Building in Ottawa.96 In India, the Pall friction device was applied to the La Gardenia housing complex97 in Delhi in 2000. More than 60 buildings all over the world are retrofitted with Pall dampers. Recently, Boeing’s Commercial Airplane Factory98 (near Seattle) — the world’s largest building in volume — was retrofitted with 537 friction dampers in tension cross bracing and diagonal bracing. In 2002, seismic retrofitting of the Eaton building in Montreal98 was carried out using 161 friction dampers, and these were installed in single diagonal bracing and chevron bracing. The first application of the Sumitomo friction damper was made in 1988, on the 31-storey Sony office building (136 m tall) in Omiya city, Japan24 ; 20 dampers were used on each floor to increase the structural resistance against moderate earthquakes. Another application was made in 1989, on the 95-m-tall Asahi Beer tower in Tokyo.24 The friction damper, as shown in Fig. 8(d), was also used to attenuate the seismic response of piping systems. In 1992, experiments were performed on piping systems with frictional supports in Japan by Suzuki et al.99 The friction support of piping systems consisted of a carbon steel shoe and a sliding plate made of Teflon, and it was observed that there is considerable reduction in the response of the piping due to energy absorption in friction. Consequently, a simpler method of analysis of piping with nonlinear supports, called the iterative response spectrum technique, using equivalent damping,43 based on energy dissipated by friction, was developed by Chiba et al. In 1997, Reddy et al.100 adopted a linearization technique using Caughy’s equivalent damping approach to analyze piping systems with friction support. A new type of friction spring seismic damper based on the friction mechanism but having a self-centering capacity was developed by Filiatrault in 2000.101 The idea behind this damper is that after an earthquake the device contributes to the structure returning to its pre-earthquake configuration. Recently, research has been carried out on connecting the adjacent structures with passive energy dissipation devices due to their ability to mitigate the dynamic


00296


167

responses as well as to reduce the chances of pounding.102–104 In 2005, Ng and Xu103 performed shake table tests on coupled building control and showed that passive friction dampers reduce the seismic response of the 12-storey main building by 40% when a 3-storey podium structure was connected to the main building by these dampers. Bhaskararao and Jangid103,104 proposed numerical models of friction dampers for two connected MDOF structures and suggested that it is not necessary to connect two adjacent structures by dampers at all floors but a smaller number of dampers at appropriate locations significantly reduces the earthquake response. Moreover, the friction damper with the optimum slip force significantly reduces the dynamic response of the coupled structures. In 2006, Bakre et al.105 suggested that bidirectional interaction of friction forces has significant effects on the response of the piping on friction supports and thus its effects must be considered in the analysis.

2.6. Viscous dampers Fluid viscous dampers (FVDs) are based on the operating principle of high velocity fluid flow through orifices. Initially these dampers had found numerous applications in the shock and vibration isolation of aerospace and defense systems. In the early 1990s, Makris and Constantinou,106 along with cooperative efforts regarding Taylor devices, performed a series of experiments to demonstrate the benefits of FVDs in bracings to attenuate the seismic response of structures. The FVD — shown in Fig. 9(a) — consists of a stainless steel piston with a bronze orifice head and an accumulator. It is filled with silicon oil. The piston head utilizes specially shaped passages, which alter the flow characteristics with fluid speed so that the force output is proportional to the piston rod velocity V α , where α is the predetermined coefficient in the range of 0.5–2. The proportionality constant is the damping constant having a small dependency on temperature. The damper will behave as a linear FVD when α = 1 and a nonlinear one otherwise. The force–displacement characteristic of the FVD is shown in Fig. 9(b). This behavior dominates for frequencies of motion below a predetermined cutoff frequency (related to the characteristics of the accumulator valves, about 4 Hz). Beyond this frequency, the fluid dampers exhibit strong stiffness

Fig. 9(a) Fluid viscous damper.

Fig. 9(b) Typical hysteresis loop of the FVD.


168

00296


increase. Later, in 1991, Makris and Constantinou107 proposed a fractional derivative model for these devices and showed that the model is capable of describing their behavior with very good accuracy. In 1993,108 they developed the macroscopic model that described the damper behavior over a large frequency range. In Russia, 3D high viscous fluid dampers or GERB dampers were successfully applied to protect primary loop piping welding from flaw growth due to operational flowinduced vibration as well as another dynamic loading like seismic loading, hydraulic hammers etc. by Kosterov et al.109 In the late 1990s, researchers110,111 focused on FVDs exhibiting a nonlinear force–velocity relationship, because of their ability to limit the peak damper force at large structural velocities while still providing sufficient supplemental damping. In 2002, Lin and Chopra112 investigated earthquake responses of SDF systems with nonlinear FVDs. It was found that nonlinear FVDs are advantageous because they achieve essentially the same reduction in system responses but with a significantly reduced damper force compared to linear viscous dampers. In 2005, Goel,113 compared the seismic response of one-storey, one-way asymmetric linear and nonlinear systems with nonlinear FVDs. It was inferred that the adverse effects of plan asymmetry may be eliminated by a combination of damper nonlinearity and system nonlinearity. In 2006, Bhaskararao and Jangid114 studied the dynamic behavior of two adjacent SDOF structures connected with a viscous damper under base acceleration and obtained closed-form expressions for the optimum damper damping of undamped structures. Earlier applications of FVDs were to reduce the structural response to wind vibrations — the Ralph Wilson Stadium (in 1993) and the Petronas Twin Towers in Malaysia (in 1995), which used 12 viscous dampers. Later, in 1994,115 VFDs were used in five buildings of the San Bernadino County Medical Center; it required a total of 233 FVDs to attenuate the seismic response. In 1994, TV Shizuoka Media City, a 65-m-tall building complex in Japan,24 installed 170 viscous damper panels in structural frames containing viscous fluid for seismic control. One of the recent applications of viscous dampers — in 2007 in Japan — is the Saitama Citizen Medical Center, a new 6-storey hospital which uses 12 FVDs with a base isolation system for seismic energy dissipation. 2.7. Base isolators Base isolation is a seismic design approach in which the structural fundamental frequency of vibration is reduced to a value lower than the predominant energy-containing frequencies of the earthquake ground motion. Extensive literature reviews were carried out in 1986 by Kelly,116 in 1990 by Buckle and Mayes117 and in 1995 by Jangid.118 Here, in addition to the brief description of the system, some additionals survey and some of the latest applications of base isolation are mentioned. There are basically two types of base isolation approaches. The first approach decouples the structure from the horizontal components of the earthquake ground


00296


Fig. 10(a) Laminated rubber bearing.

169

Fig. 10(b) Laminated lead plug bearing.

motion by interposing a layer with low horizontal stiffness between the structure and the foundation, and the second approach works by limiting the transfer of shear across the isolation interface through the use of sliding systems. In the 1980s, Kelly and Hodder119 first proposed the former approach, in which experimental work was performed on laminated rubber bearings (LRBs) and laminated lead plug bearings (LLPBs) see Figs. 10(a) and 10(b) respectively. Consequently, Kelly and Beucke120 developed the latter approach in 1983. One of the friction base isolation types of systems is lead–bronze plate sliding on stainless steel with an elastomeric bearing. The other type is a friction pendulum system with special interfacial material sliding on stainless steel and a roller bearings system. A lot of theoretical work has been carried out by many researchers121–125 to investigate the effectiveness of base isolation in reducing the earthquake motion transferred to the structure and understanding the parametric behavior of such structures. In the late 1980s, a new type of system having Teflon-coated steel plates that are in friction contact with each other and containing a central core of rubber called a resilient friction base isolator was proposed by Mostaghel and Khodaverdian.126 Later, in 1996, Jangid127 obtained the optimum damping for structures isolated with such systems. Such a type has been used in common for several projects in the US, for both new and retrofit construction. In 1993, Lin and Hone128 proposed a new system of free circular rolling rods between the base and the foundation of the structure. This system had a low value of the rolling friction coefficient and hence was quite effective. However, it resulted in large peak residual base displacements. In 1996, Jangid and Londhe129 proposed that the shape of the rolling rods be elliptical instead of circular and suggested that increase in the eccentricity of the rolling rods decreased the peak base displacements. However, they found that the effectiveness of the rolling rods decreased with increase in the flexibility of superstructure. In 2003, an advanced isolator called the multiple friction pendulum system (MFPS) was proposed by Tsai.130 It consisted of two spherical concave surfaces and a special articulated slider which could be another sliding surface. Based on this special design, the displacement capacity was twice that of the friction pendulum system with a single sliding surface. They also performed a series of experiments on structures with the MFPS. In 2005, Jangid131 carried out a comparative study of the response of structures isolated by sliding systems with conventional and hysteretic models of the frictional force of the sliding


170

00296


system. It was found that the conventional model is more computationally efficient than the hysteretic model. Later, in 2006, a comparative study was made to evaluate the seismic response of the liquid storage tanks,132 and thereafter cable-stayed bridges.133 Optimal values for isolators were suggested for reducing the response of these structures. In 2007, optimum LRBs134 with yield strength in the range of 10%–15% of the total weight of the building were obtained for near-fault motions. In 2008, Jangid,135 using the time-dependent equivalent linearization technique, obtained equivalent linear stochastic seismic response of isolated bridges. Finally, closed-form expressions for the optimum yield strength of LRBs and the corresponding response of the isolated bridge system were proposed which can be used in the initial design of the seismic isolation system for the bridges. In 1985, the first base-isolated building, constructed on base isolators in the US, appeared: the Foothill Communities Law and Justice Center, in San Bernardino county.136 The building is four-storied, with a full basement for the isolation system, consisting of 98 isolators of LRBs. One of the largest base-isolated buildings in the world is the West Japan Postal Computer Center, located in Sanda, Kobe. This six-storied, 47 000 sq m structure is supported on 120 elastomeric isolators with a number of additional steel and lead dampers.136 San Francisco’s Asian Art Museum, constructed of structural steel and unreinforced brick masonry, was in the early 21st century retrofitted with base isolators.137 3. Conclusions In this paper the basic concepts of passive seismic response control devices are mentioned and their recent developments and applications are discussed. In this overview it is observed that a range of passive devices can be used for seismic response attenuation. But choosing a specific type of device for a structure depends on the design considerations. For instance, tuned liquid dampers can be used effectively for structures having frequencies of up to 2 Hz. The application of tuned mass dampers has to take into consideration the amplitude of the moving parts during large excitations. Also, perfect tuning is difficult to achieve. The performance of viscoelastic dampers depends on frequencies of excitation and ambient temperature, while viscous dampers may have the possibility of leakage of fluid. Friction dampers require a specially designed durable friction surface, which minimizes the stick-slip phenomenon. Metallic yield dampers slightly increase the frequency of the structure, so care should be taken in the design such that there is no augmentation of response due to a shift of frequency in the peak region of response spectra. New material dampers like shape memory alloy dampers have gained importance recently, as they are made of shape memory alloy wires, which are easy to install and have an additional capacity for recentering the structure if it goes into nonlinear deformation. Progressive efforts are being made toward easy installation, application and development of theoretical models of SMA devices.


00296


171

The main physical causes of damping are irreversible processes in material, energy loss at joints and radiation by acoustic and structure-borne sound. There is a lot of scope for developing new, simplified techniques to accurately model the damping properties of structures with dampers. This comprehensive overview states that the passive response control devices should be extensively used in structural engineering practice for preventing earthquake disasters, and that proper guidelines should be included in codes for the use of such devices. Acknowledgments The authors would like to thank Shri. K. K. Vaze, Dr. A. K. Ghosh and Shri. H. S. Kushwaha for their help and support in carrying out the literature survey. References 1. ASCE Standard 4–98, Seismic analysis of safety-related nuclear structures (1998). 2. IS 1893–2002 Indian Standard, Criteria for earthquake resistant design of structures, Part I: General provisions and buildings (5th revision, 2002). 3. IAEA–TECDOC–1347, Consideration of external events in the design of nuclear facilities other than power plants, with emphasis on earthquakes, IAEA (2003). 4. ATC, Proc. Sem. Seismic Isolation, Passive Energy Dissipation, and Active Control. Report No. ATC-17-1, Applied Technology Council, San Francisco, California, 1993. 5. EERI, Theme issue: Passive energy dissipation, Earthq. Spectra 9(3) (1993). 6. T. T. Soong and M. C. Constantinou, Passive and Active Structural Vibration Control in Civil Engineering (Springer, New York, 1994). 7. M. D. Symans and M. C. Constantinou, Semi-active control systems for seismic protection of structures: a state-of-the-art review, Eng. Struct. 21 (1999) 469–487. 8. H. Yoshioka, J. C. Ramallo and B. F. Spencer Jr., “Smart” base isolation strategies employing magneto-rheological dampers, J. Eng. Mech. ASCE 128 (2002) 540–551. 9. H. Iemura and M. H. Pradono, Passive and semi-active seismic response control of a cable-stayed bridge, J. Struct. Contr. 9 (2002) 189–204. 10. K. Park, I. Lee, H. Jung and J. Park, Integrated passive–active system for seismic protection of a cable-stayed bridge, J. Earthq. Eng. Struct. Dynam. 7 (2003) 615–633. 11. J. C. Ramallo, E. A. Johnson and B. F. Spencer Jr., Smart base isolation systems, J. Eng. Mech. ASCE 128 (2002) 1088–1100. 12. N. Makris and S. Chang, Effect of viscous, viscoplastic and friction damping on the response of seismic isolated structures, Earthq. Eng. Struct. Dynam. 29 (2000) 85–107. 13. B. B. Soneji and R. S. Jangid, Passive hybrid systems for earthquake protection of cable-stayed bridge, Eng. Struct. 29 (2007) 57–70. 14. US Panel on Structural Control Research, Structural control: Past, present, and future, Special Issue of J. Eng. Mech. 123(9) (1997). 15. P. Mahmoodi, Structural dampers, J. Struct. Div. ASCE 95 (1969) 1661–1672. 16. P. Mahmoodi, Design and analysis of viscoelastic vibration dampers for structures, in Proc. INOVA-73 World Innovative Week Conference (Elsevier, London, 1974), pp. 25–39.


172

00296


17. Gerb geselischaft f¨ ur isolierung mbH & Co KG, Vibration isolation systems, 13407 Berlin, Roedernallee (1978), pp. 174–176. 18. R. Zhang, T. T. Soong and P. Mahmoodi, Seismic response of steel frame structures with added viscoelastic dampers, Earthq. Eng. Struct. Dynam. 18(9) (1989) 389–396. 19. R. Zhang and T. T. Soong, Seismic design of viscoelastic dampers for structural applications, J. Struct. Eng. ASCE 118(5) (1992) 1375–1392. 20. K. C. Chang, T. T. Soong, S. T. Oh and M. L. Lai, Study of ambient temperature of viscoelastically damped structure, J. Struct. Eng. ASCE 118(7) (1992) 1955–1973. 21. C. S. Tsai, Innovative design of viscoelastic dampers for seismic mitigation, Nucl. Eng. Des. 139 (1993) 165–182. 22. K. L. Shen and T. T. Soong, Modeling of viscoelastic dampers for structural applications, J. Eng. Mech. ASCE 121(6) (1995) 694–701. 23. M. L. Lai, K. C. Chang, T. T. Soong, D. S. Hao and Y. C. Yeh, Full-scale viscoelastically damped steel frame, ASCE J. Struct. Eng. 121(1) (1995) 1443–1447. 24. Y. Kitagawa and M. Midorikawa, Seismic isolation and passive response-control buildings in Japan, Smart Mater. Struct. 7 (1998) 581–587. 25. E. Elsesser, M. Jokerst and S. Naaseh, Historic upgrades in San Francisco, J. Civil. Eng. ASCE (1997). 26. T. Fujita (ed.), Seismic isolation and response control for nuclear and nonnuclear structures, in Special Issue of the 11th Int. Conf. SMiRT, Tokyo (1991). 27. W. Lin and A. K. Chopra, Asymmetric one-storey elastic systems with non-linear viscous and viscoelastic dampers: Earthquake response, Earthq. Eng. Struct. Dynam. 32 (2003) 555–577. 28. J. M. Kelly, R. I. Skinner and A. J. Heine, Mechanisms of energy absorption in special devices for use in earthquake resistant structures, Bull. N.Z. Soc. Earthq. Eng. 5(3) (1972) 63–73. 29. A. S. Whittaker, V. V. Bertero, C. L. Thompson and L. J. Alonso, Seismic testing of steel plate energy dissipation devices, Earthq. Spectra 7(4) (1991) 563–604. 30. K. C. Tsai, H. W. Chen, C. P. Hong and Y. F. Su, Design of steel triangular plate energy absorbers for seismic-resistant construction, Earthq. Spectra 9(3) (1993) 505– 528. 31. T. Suzuki, T. Sano and Y. Takahashi, New damage control design using Y-shaped brace Damper, in Proc. Symp. New Direction in Seismic Design, Tokyo (1995), pp. 301–306. 32. S. Scheneider, Piping seismic test with energy absorbing devices, EPRI NP-2902, Electric Power Research Institute (1983). 33. Y. Namita, M. Shigeta, T. Yoshinaga, N. Gotoh and J. Kawahata, The application of elasto-plastic support devices for a piping system, JSME Int. J. 34(1) (1991) 42–49. 34. R. I. Skinner, R. G. Tyler, A. J. Heine and W. H. Robinson, Hysteretic dampers for the protection of structures from earthquakes, Bull. N.Z. Soc. Earthq. Eng. 13(1) (1980) 22–36. 35. P. R. Boardman, B. J. Wood and A. J. Carr, Union House — A cross-braced structure with energy dissipaters, Bull. N.Z. Nat. Soc. Earthq. Eng. 16(2) (1983) 83–97. 36. L. G. Cormack, Design and construction of the major bridges on the Mangaweka rail deviation, Trans. IPENZ 15, I/CE (1988) 16–23. 37. C. L. Perry, E. A. Fierro, H. Sedarat and R. E. Scholl, Seismic upgrade in San Francisco using energy dissipation devices, Earthq. Spectra 9(3) (1992) 559–579. 38. C. S. Tsai and K. C. Tsai, TPEA Device as seismic damper for high rise buildings, J. Eng. Mech. 121(10) (1995) 1075–1081.


00296


173

39. R. E. Scholl, Design criteria for yielding and friction energy dissipaters, in Proc. ATC 17-1 on Seismic Isolation, Energy Dissipation and Active Control 2, pp. 485–495. 40. J. C. De la Llera, C. Esguerra and J. L. Almazan, Earthquake behavior of structures with copper energy dissipators, Earthq. Eng. Struct. Dynam. 33 (2004) 329–358. 41. M. C. Phocas and A. Pocanschi, Steel frames with bracing mechanism and hysteretic dampers, Earthq. Eng. Struct. Dynam. 32 (2003) 811–825. 42. Y. M. Parulekar, G. R. Reddy, K. K. Vaze and K. Muthumani, Passive control of seismic response of piping systems, J. Pressure Vessels Technol. 128(3) (2006) 364–369. 43. T. Chiba, H. Kobayashi, R. Yokoi, K. Suzuki, T. Mitsumori, T. Watanabe, N. Shimizu, N. Ogawa and C. Minowa, An experimental study of seismic responses of piping systems with the friction. Part II: Simplified method focused on the reduction effect of the friction, ASME PVP Conf. Seismic Eng. 237(2) (1992) 243–248. 44. Z. Chen, H. Ge, A. Kasai and T. Usami, Simplified seismic design approach for steel portal frame piers with hysteretic dampers, Earthq. Eng. Struct. Dynam. 36 (2007) 541–562. 45. S. V. Bakre, R. S. Jangid and G. R. Reddy, Optimum X plate dampers for seismic response control of piping systems, J. Pressure Vessels Piping 83 (2006) 672–685. 46. W. H. Robinson and L. R. Greenbank, An extrusion energy absorber suitable for the protection of structures during an earthquake, Earthq. Eng. Struct. Dynam. 4 (1976) 251–259. 47. Y. M. Parulekar, G. R. Reddy, K. K. Vaze and H. S. Kushwaha, Lead extrusion dampers for reducing seismic response of coolant channel assembly, Nucl. Eng. Des. 227 (2004) 175–183. 48. R. W. G. Blakeley, Analysis and design of bridges incorporating mechanical energy dissipating devices for earthquake resistance, in Proc. Workshop Earthquake Resistant Highway Bridges, ATC-6-1, USA (1979), pp. 314–342. 49. A. W. Charleson, P. D. Wright and R. I. Skinner, Wellington Central Police station: Base isolation of an essential facility, in Proc. Pacific Conf. Earthquake Engineering, New Zealand, Vol. 2, pp. 377–388. 50. E. J. Graesser and F. A. Cozzarelli, Shape memory alloys as new material for aseismic isolation, J. Eng. Mech. ASCE 117 (1991) 2590–2608. 51. J. Van Humbeeck, Cycling e!ects, fatigue and degradation of shape memory alloys, J. de Phys. 4 (1991) 189–197. 52. M. Dolce, D. Cardone and R. Marnetto, Implementation and testing of passive control devices based on shape memory alloys, Earthq. Eng. Struct. Dynam. 29 (2000) 945–968. 53. R. Sreekala, K. Muthumani, N. Lakshmanan, N. Gopalkrishnan, K. Satishkumar, G. R. Reddy and Y. M. Parulekar, Shape memory alloys for seismic response control, J. Struct. Eng. SERC 33(5) (2007) 383–389. 54. H. Frahm, Device for damping vibration of bodies, US Patent No. 989–958, 1911. 55. J. P. Den Hartog, Mechanical Vibrations (McGraw-Hill, New York, 1947). 56. R. J. McNamara, Tuned mass dampers for buildings, J. Struct. Div. ASCE 103 (1977) 1985–1998. 57. R. W. Luft, Optimal tuned mass dampers for buildings, J. Struct. Div. ASCE. 105 (1979) 2766–2772. 58. G. B. Warburton, Optimum absorber parameters for various combinations of response and excitation parameters, Earthq. Eng. Struct. Dynam. 10 (1982) 381–401. 59. A. M. Kaynia, D. Venerziano and J. M. Biggs, Seismic effectiveness of tuned mass dampers, J. Struct. Div. ASCE 107(8) (1981) 1465–1484.


174

00296


60. J. R. Sladek and R. E. Klinger, Effect of tune mass dampers of seismic response, J. Struct. Eng. ASCE 109 (1983) 2004–2009. 61. A. J. Clark, Multiple tuned mass dampers for reducing earthquake-induced building motion, in Proc. 9th World Conf. Earthquake Engineering, Tokyo, Japan, Vol. 5 (1988), pp. 779–784. 62. A. Kareem and S. Kline, Performance of multiple mass dampers under random loading, J. Struct. Eng. ASCE 121(2) (1995) 348–361. 63. R. S. Jangid, Dynamic characteristics of structures with multiple tuned mass dampers, Struct. Eng. Mech. 3 (1995) 497–509. 64. R. S. Jangid and T. K. Datta, Performance of multiple tuned mass damper for torsionally coupled system, Earthq. Eng. Struct. Dynam. 26 (1997) 307–317. 65. C. C. Lin, J. M. Ueng and T. C. Huang, Seismic response reduction of irregular buildings using passive tuned mass dampers, Eng. Struct. 22 (1999) 513–524. 66. J. Wu and G. Chen, Optimization of multiple tuned mass dampers for seismic response reduction, in Proc. 2000 Am. Contr. Conf., Chicago (2000). 67. C.-X. Li, Optimum multiple tuned mass dampers for structures under the ground acceleration based on DDMF and ADMF, Earthq. Eng. Struct. Dynam. 31 (2002) 897–919. 68. C. L. Lee, Y.-T. Chen, L.-L. Chung and Y.-P. Wang, Optimal design theories and applications of tuned mass dampers, Eng. Struct. 28 (2006) 43–53. 69. S. V. Bakre and R. S. Jangid, Optimum parameters of tuned mass damper for damped main system, Struct. Contr. Health Monitoring 14 (2006) 448–470. 70. T. Kobori, Future direction on research and development of seismic-responsecontrolled structure, in Proc. 1st World Conf. Structural Control, Pasadena, California (1994), pp. 19–31. 71. V. J. Modi and F. Welt, Vibration control using notation dampers, in Proc. Int. Conf. Flow Induced Vibrations, Brighton, UK (1987), pp. 369–376. 72. F. Welt and V. Modi, Vibration damping through liquid sloshing: Nonlinear analysis, Trans. ASME 114 (1992) 10–16. 73. F. Welt and V. Modi, Vibration damping through liquid sloshing: Experimental results, Trans. ASME 114 (1992) 18–23. 74. Y. Fujino, B. Pacheco, P. Chaiseri and L. Sun, Parametric studies on TLD using circular container by free-oscillation experiments, Struct. Eng. Earthq. Eng. 5(2) (1988) 381–391. 75. Y. Fujino, L. Sun, B. Pacheco and P. Chaiseri, Tuned liquid damper for suppressing horizontal motion of structures, J. Eng. Mech. 118 (1992) 2017–2029. 76. L. Sun, Y. Fujino and K. Koga, A model of tuned liquid damper for suppressing pitching motions of structures, Earthq. Eng. Struct. Dynam. 24 (1995) 625–636. 77. L. Sun, Y. Fujino, P. Chaiseri and B. Pacheco, The properties of tuned liquid damper using a TMD analogy, Earthq. Eng. Struct. Dynam. 24 (1995) 967–679. 78. J. Yu, T. Wakahara and D. Reed, A non-linear numerical model of the tuned liquid damper, Earthq. Eng. Struct. Dynam. 28 (1999) 671–686. 79. Y. Yamura, Y. Fujii, T. Ohtsuki, T. Wakahara and R. Koshaka, Effectiveness of tuned liquid dampers under wind excitations, Eng. Struct. 17 (1995) 609–621. 80. Y. Tamura, R. Kohsaka, O. Nakamura, K. Miyashita and V. J. Modi, Wind-induced responses of an airport tower–efficiency of tuned liquid damper, J. Wind Eng. Ind. Aerodynam. 65 (1996) 121–131. 81. K. Yamamoto and M. Kawahara, Structural oscillation control using tuned liquid damper, Comput. Struct. 71 (1999) 435–446.


00296


175

82. P. Banerji, M. Murandi, A. Shah and N. Popplewell, Tuned liquid dampers for controlling earthquake response of structures, Earthq. Eng. Struct. Dynam. 29 (2000) 570–602. 83. R. C. Savyanavar, G. R. Reddy, Y. M. Parulekar, P. Kumar, A. Rama Rao, S. P. Chavan, K. K. Vaze, A. K. Ghosh and H. S. Kushwaha, Experimental evaluation and retrofitting of structure subjected to earthquake loading with circular tuned liquid damper (TLD), J. Struct. Eng. SERC 33(6) (2007) 479–486. 84. S. Lee, E. C. Park, K. W. Min, S. H. Lee, L. Chung and J. H. Park, Real-time hybrid shaking table testing method for the performance evaluation of a tuned liquid damper controlling seismic response of building structures, J. Sound Vib. 302 (2007) 596–612. 85. F. Sakai, S. Takaeda and T. Tamaki, Tuned liquid column dampers — A new type device for suppression of building vibrations, in Proc. Int. Conf. Highrise Buildings, China, Vol. 2 (1989), pp. 926–931. 86. F. Sakai, S. Takaeda and T. Tamaki, Tuned liquid column dampers (TLCD) for cable-stayed bridges, in Proc. Specialty Conf. Innovation in Cable-Stayed Bridges, Japan (1991), pp. 197–205. 87. A. Y. J. Won, J. A. Pires and M. A. Haroun, Stochastic seismic performance evaluation of tuned liquid column dampers, Earthq. Eng. Struct. Dynam. 25 (1996) 1259–1274. 88. A. Kareem, The next generation of tuned liquid dampers, in Proc. 1st World Conf. Structural Control, Los Angeles (1994), pp. 19–28. 89. F. Sadek, B. Mohraz and H. S. Lew, Single- and multiple-tuned liquid column dampers for seismic applications, Earthq. Eng. Struct. Dynam. 27 (1998) 439–463. 90. K. M. Shum and Y. L. Xu, Multiple-tuned liquid column dampers for torsional vibration control of structures: Experimental investigation, Earthq. Eng. Struct. Dynam. 31 (2002) 977–991. 91. A. S. Pall, C. Marsh and P. Fazio, Friction joints for seismic control of large panel structures, J. Prestressed Concrete Inst. 6 (1980) 38–61. 92. A. S. Pall and C. Marsh, Seismic response of friction damped braced frames, J. Struct. Div. ASCE 108(9) (1982) 1313–1323. 93. A. Filiatrault and S. Cherry, Performance evaluation of friction damped braced steel frames under simulated earthquake loads, Earthq. Spectra 3(1) (1987) 57–78. 94. I. D. Aiken and J. M. Kelly, Earthquake simulator testing and analytical studies of two energy absorbing systems for multi-storey structures, Report No. UCB/EERC90/03, University of California, Berkeley, California, USA (1990). 95. D. K. Nims, P. J. Richter and R. E. Bachman, The use of the energy dissipating restraint for seismic hazard mitigation, Earthq. Spectra 9(3) (1993) 467–489. 96. A. S. Pall, V. Verganelakis and C. Marsh, Friction-dampers for seismic control of concordia university library building, in Proc. Fifth Can. Conf. Earthq. Eng., Ottawa (1987), pp. 191–200. 97. C. Ramesh, M. Masand, S. K. Nandi, C. P. Tripathi, R. Pall and A. Pall, Frictiondampers for seismic control of La Gardenia Towers South City, Gurgaon, India, in 12th World Conf. Earthq. Eng., Auckland 2000 (2008). 98. C. Pasquin, A. N. Leboeuf and T. Pall, Friction dampers for seismic rehabilitation of Eaton Building, Montreal, in 4th Struct. Specialty Conf. Can. Soc. Civ. Eng. (2002). 99. K. Suzuki, T. Watanabe, T. Mitsumori, N. Shimizu, T. Chiba, H. Kobayashi, R. Yokoi, N. Ogawa and C. Minowa, An experimental study of seismic responses of piping systems with the friction. Part I: Vibration test by using large scale shaking table, ASME PVP Seismic Eng. 237(2) (1992) 237–241.


176

00296


100. G. R. Reddy, K. Suzuki and T. Watanabe, Linearization techniques for seismic analysis of piping system on friction support, J. Pressure Vessel Technol. 121 (1999) 103–108. 101. A. Filiatrault, R. Tremblay and R. Kar, Performance evaluation of friction spring seismic damper, J. Struct. Eng. ASCE 126(4) (2000) 491–499. 102. C. L. Ng and Y. L. Xu, Seismic response control of a building complex utilizing passive friction damper: Experimental investigation, Earthq. Eng. Struct. Dynam. 35 (2006) 657–677. 103. A. V. Bhaskararao and R. S. Jangid, Seismic analysis of structures connected with friction dampers, Eng. Struct. 28 (2006) 690–703. 104. A. V. Bhaskararao and R. S. Jangid, Harmonic response of adjacent structures connected with a friction damper, J. Sound Vib. 292 (2006) 710–725. 105. S. V. Bakre, R. S. Jangid and G. R. Reddy, Response of piping system on friction support to bi-directional excitation, Nucl. Eng. Des. 237 (2006) 124–136. 106. N. Makris and M. C. Constantinou, Viscous dampers: Testing modeling and application in vibration and seismic isolation, Report No. NCEER-90-O028, Buffalo, New York, 1990. 107. N. Makris and M. C. Constantinou, Fractional derivative model for viscous dampers, J. Struct. Eng. ASCE 117(9) (1991) 2708–2724. 108. N. Makris, M. C. Constantinou and G. F. Dargush, Analytical model of viscoelastic fluid dampers, J. Struct. Eng. ASCE 119(11) (1993). 109. V. V. Kostarev, A. M. Berkovski and A. J. Schukin, Upgrading of dynamic reliability and life extension of piping by means of high viscous damper technology, in Proc. PVP, ASME Conf., Boston (1999). 110. M. D. Symans and M. C. Constantinou, Passive fluid viscous damping systems for seismic energy dissipation, ISET J. Earthq. Technol. 35(4) (1998) 185–206. 111. G. Pekcan, J. B. Mander and S. S. Chen, Fundamental considerations for the design of non-linear viscous dampers, Earthq. Eng. Struct. Dynam. 28 (1999) 1405–1425. 112. W. H. Lin and A. K. Chopra, Earthquake response of elastic SDF systems with nonlinear fluid viscous dampers, Earthq. Eng. Struct. Dynam. 31 (2002) 1623–1642. 113. R. Goel, Seismic response of linear and non-linear asymmetric systems with nonlinear fluid viscous dampers, Earthq. Eng. Struct. Dynam. 34 (2005) 825–846. 114. A. V. Bhaskararao and R. S. Jangid, Optimum viscous damper for connecting adjacent SDOF structures for harmonic and stationary white-noise random excitations, Earthq. Eng. Struct. Dynam. 36 (2007) 563–571. 115. J. W. Asher, R. P. Young and R. D. Ewing, Seismic isolation design of the San Bernardino County Medical Center replacement project, J. Struct. Des. Tall Bldg. 5 (1996) 265–279. 116. J. M. Kelly, A seismic base isolation: A review and bibliography, Soil Dynam. Earthq. Eng. 5 (1986) 202–216. 117. I. G. Buckle and R. L. Mayes, Seismic isolation: History, application and performance — A world overview, Earthq. Spectra 6 (1990) 161–202. 118. R. S. Jangid and T. K. Dutta, Seismic behaviour of base isolated buildings: A state of the art review, in Proc. Inst. Civ. Eng. Struct. Bldgs. 110 (1995) 186–203. 119. J. M. Kelly and S. B. Hodder, Experimental study of lead and elastomeric dampers for base isolation system in laminated neoprene bearings, Bull. N.Z. Nat. Soc. Earthq. Eng. 15 (1982) 53–67. 120. J. M. Kelly and K. E. Beucke, A frictional damped base isolation system with fail-safe characteristics, Earthq. Eng. Struct. Dynam. 11 (1983) 33–56.


00296


177

121. M. C. Constantinou and I. G. Tadjbakhsh, Optimum characteristics of isolated structures, J. Struct Eng. ASCE 111 (1985) 2733–2750. 122. M. C. Constantinou and I. G. Tadjbakhsh, Hysteretic dampers in base isolation: Random approach, J. Struct. Eng. ASCE 111 (1985) 705–721. 123. F. Fan and G. Ahmadi, Floor response spectra for base-isolated multi-storey structures, Earthq. Eng. Struct. Dynam. 19 (1990) 377–388. 124. R. S. Jangid and T. K. Datta, Non-linear response of torsionally coupled base isolated structure, J. Struct. Eng. ASCE 120 (1994) 1–22. 125. R. S. Jangid and T. K. Datta, The stochastic response of asymmetric base isolated buildings, J. Sound Vib. 179 (1995) 463–473. 126. N. Mostaghel and H. Khodaverdian, Dynamics of resilient-friction base isolator (RFBI), Earthq. Eng. Struct. Dynam. 15 (1987) 379–390. 127. R. S. Jangid, Optimum damping in a nonlinear base Isolation system, J. Sound Vib. 189(4) (1996) 477–487. 128. T. W. Lin and C. C. Hone, Base isolation by free rolling rods under basement, Earthq. Eng. Struct. Dynam. 22 (1993) 261–273. 129. R. S. Jangid and Y. B. Londhe, Effectiveness of elliptical rolling rods for base isolation, J. Struct Eng. ASCE 124 (1998) 469–472. 130. C. S. Tsai, T. C. Chiang and B. J. Chen, Shaking table tests of a full scale steel structure isolated with MFPS, ASME Pressure Vessels and Piping Conference, Ohio, USA, Vol. 466 (2003) 41–47. 131. R. S. Jangid, Computational numerical models for seismic response of structures isolated by sliding systems, Struct. Contr. Health Monitoring 12 (2005) 117–137. 132. M. B. Jadhav and R. S. Jangid, Response of base-isolated liquid storage tanks to near-fault motions, Struct. Eng. Mech., USA/Korea, Vol. 23 (2006) 615–634. 133. B. B. Soneji and R. S. Jangid, Effectiveness of seismic isolation for cable-stayed bridges, Int. J. Struct. Stab. Dynam. 6 (2006) 77–96. 134. R. S. Jangid, Optimum lead–rubber isolation bearings for near-fault motions, Eng. Struct. 29 (2007) 2503–2513. 135. R. S. Jangid, Equivalent linear stochastic seismic response of isolated bridges, J. Sound Vib. 309 (2008) 805–822. 136. J. M. Kelly, Base isolation: Origins and development, EERC News 12(1) (1998). 137. S. J. Tuholski and P. E. Rodler, San Francisco’s new Asian Art Museum, in 13th World Conf. Earthq. Eng., Canada (2004).

PASSIVE RESPONSE CONTROL SYSTEMS FOR ...

PASSIVE RESPONSE CONTROL SYSTEMS FOR ...

Suggest Documents

PASSIVE RESPONSE CONTROL SYSTEMS FOR ...

Smart Systems for Structural Response Control

COMPOSITIONS OF PASSIVE BOUNDARY CONTROL SYSTEMS ...

Control Schemes for Passive Teleoperation Systems ... - Springer Link

Comparison of Different Passive Control Systems for ...

Control Schemes for Passive Teleoperation Systems ... - Springer Link

PASSIVE ENVIRONMENTAL CONTROL ...

Passive Cooling Systems - Pisa

Passive Phosphorus Removal Systems

Assessing the Control Systems Capacity for Demand Response in ...

Assessing the Control Systems Capacity for Demand Response in ...

Adaptive Fuzzy Torque Control of Passive Torque Servo Systems

MIMO Passive Control Systems Are Not Necessarily Robust

Design Optimization of Active and Passive Structural Control Systems

Passive Control Architecture for Virtual Humans

Nonlinear control of hammerstein systems with passive nonlinear ...

Passive control of instabilities in combustion systems with heat

Optimal Design of Passive Control Systems Using Stiffness

Cauchy problems from networks of passive boundary control systems

development and application of passive structural control systems in ...

Control Passive Mobile Robots for Object

Response of passive modified atmospheric

passive dynamic controllers for nonlinear mechanical systems

Passive Sonar Fusion for Submarine C Systems