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- The Application of Energy Dissipating Damping Devices to an Engineered Structure or
Mechanism – D. Taylor
The design of a structure or mechanism subjected to shock and vibration can be greatly improved
by the addition of isolation or damping devices. Improvements Include: Reduced Deflection and
Stresses, Reduced Weight, Improved Biodynamics, Longer Fatigue Life, Architectural
Enhancement and Reduced Cost.
- Bridge Design Example for 2nd US-Japan Workshop on Protective Systems for Bridges –
M. Constantinou, P. Tsopelas
This paper reports on a non-linear analysis of a bridge supported on sliding bearings with
elastomeric restoring springs and viscous dampers. Results were verified with shake table tests.
- Commentary on Corrosion at Bimetallic Contacts and its Alleviation – BSI Standards
This document shows designers how to avoid corrosion due to the interaction of different metals
and alloys at bimetallic contacts. Section one describes the conditions that lead to corrosion at
bimetallic contacts and methods to alleviate it. The tables in Section two show the degree of
corrosion likely to occur at bimetallic contacts exposed to atmosphere and water.
- Earthquake Protective Systems for Buildings, Bridges and other Structures – Taylor Devices
This is a one page description of Taylor Devices viscous damping systems for earthquake
- Electrorheological Fluid Dampers: Testing, Modeling and Applications in Vibration –
N. Makris, D. Hill, D. Taylor
This paper describes an NSF funded project to investigate viscous dampers with controlled variable
damping constant, using electrorheological fluid. Experimental results correlate well with
- Experimental Study of Seismic Response of Buildings with Supplemental Fluid Dampers –
M. Constantinou, M. Symans
A quarter scale model of a three story steel moment frame building was tested on a shake table
using time histories from a large number of earthquakes including Taft, El Centro, etc. Tests were
conducted both without dampers and with varying numbers of dampers. Test results correlated
well with the analytical predictions. Conclusions; viscous dampers reduced story drifts by 30% to
70%. These reductions are comparable to those achieved by other energy dissipating systems such
as viscoelastic, friction and yielding steel dampers. However, the use of fluid dampers also reduced
story shear forces by 40% to 70%, while other energy absorbing devices showed no significant
- Fluid Viscous Damper for Improving the Earthquake Resistance of Buildings –
M. Constantinou, M. Symans, D. Taylor
This paper is a condensed version of Technical Paper 6.
- Fluid Viscous Dampers in Applications of Seismic Energy Dissipation and Seismic Isolation –
M. Constantinou, M. Symans, P. Tsopelas, D. Taylor
Experimental study of both a moment frame building and a single span bridge, both with and
without viscous dampers, are described here. Additions of viscous dampers significantly reduced
both drift and shear forces.
- Golden Gate Bridge Seismic Retrofit Design Specs
This specification, prepared jointly by TY Lin and Imbsen Associates, describes the requirements
for the viscous dampers to be used in the retrofit of the Golden Gate Bridge. The specification
includes wind excitation as well as seismic, and also describes testing requirements.
- Investigation of Light Pole Base Integrity – J. Mander, S. Chen, K. Shah, A. Madan
Light poles at Rich Stadium in Buffalo, N.Y., were showing incipient failure of their hold-down
bolts, due to wind excitation. This paper describes the measures used to alleviate this problem,
including the addition of viscous dampers between the stadium structure and a point around one
third up on the light poles. This modification was very successful.
- Long Term Life Cycle Evaluation of Taylor Devices Products – J. Dragonette
A number of Taylor Devices produced between 1956 and 1965 are kept in storage and are
periodically evaluated for corrosion and deterioration. This report describes the present day
condition of these dampers and shock absorbers. All are fully functional and corrosion free.
- Passive and Active Fluid Dampers in Structural Applications – M. Shinozuka, M.
Constantinou, R. Ghanem
Analytical and experimental results demonstrate that the performance improvements from active
control systems can also be achieved with passive and semi-active fluid dampers. However,
passive or semi-active fluid dampers offer the advantages of low cost, no or minimal demand for
external power, longevity and reliability.
- Passive and Active Structural Vibration Control in Civil Engineering – T. Soong,
This paper describes a large variety of passive energy dissipating devices which can be used within
a structural system to absorb seismic energy. These devices can produce significant reductions of
inter-story drifts in moment- resisting frames. Furthermore, these devices may under elastic
conditions, reduce the design forces..
- Precise Positioning Shock Isolators – D. Taylor, D. Lee
Conventional approaches to the shock isolation of delicate systems often involve the use of low
frequency shock mountings. This type of mounting is not usable on systems where precise
alignment must be maintained over a long period of time. This paper describes a new type of
isolator which combines excellent attenuation with the ability to precisely maintain system
alignment in the pre and post shock environment. This new shock absorber acts as a rigid link
under normal conditions. Then, when a shock occurs, it strokes in both tension and compression
with damping in both directions. After things calm down the shock returns precisely to its original
length. Computer simulation and test results are included.
- Reduction of Shock Response Spectra using Various Types of Shock Isolation Mounts –
This experiment demonstrated how various types of shock absorbers can reduce the overall shock
response spectra of a structure subjected to high impact shock. This was accomplished by
measuring the acceleration on a weight dropped onto three different shock absorbers from various
heights and analyzing the resulting data. A baseline test was performed with a steel hard mount.
This was followed by tests with three different soft isolation mounts; a half inch thick neoprene
pad, a urethane rubber tube on its side and a hydraulic liquid spring type shock absorber. Results
show that both the dominant frequencies and the peak acceleration get lower as the isolation system
gets softer. This information can be valuable in the design of isolation systems.
- Rockwell Viscous Dampers - Specifications
This specification covers the set of ten linear fluid viscous dampers along with their mounting brackets and pins for the Rockwell Building located at Jamboree Road and Birch in Newport
Beach, California. These dampers provide an output force in either tension of compression that is
directly proportional to the relative velocity between the two ends of the dampers. The damper
output force varies only with velocity and does not change with damper stroke position or
orientation angle. The function of the dampers is to absorb earthquake energy, thereby reducing the
amount the building moves when an earthquake occurs.
- San Bernardino County Medical Center - Specification
This specification covers the set of 186 fluid viscous dampers used on the five buildings of the new
San Bernardino County Medical Center located in Colton, California. Three major faults are close
to this location. The dampers operate in parallel with elastomeric base isolators, and reduce the
required isolator stroke from +/- 48 inches to +/- 22 inches. This specification is very detailed and
includes testing requirements.
- Seismic Control of Structures with Damped Resonant Appendages – R. Villaverde
This paper shows how Tuned Mass Dampers can provide seismic protection for structures. These
dampers consist of a relatively small mass, a spring, and a dashpot attached to a point of maximum
vibration and in resonance with the structure to which they are attached. They are widely used to
control the response of buildings, bridges, towers, chimneys and other structures to wind forces,
machine vibrations and occupant activity. For the most part however, these dampers have been
considered ineffective to reduce the seismic response of structures. This paper demonstrates that
such devices can be used effectively to control the seismic response of structures. The paper
presents a basic mechanism that explains under what conditions such dampers may work effectively
under earthquake loads. It also provides recommendations for the selection of the mass, stiffness
and damping factors. It includes the results of a series of numerical and experimental tests which
verify that properly designed Tuned Mass Dampers effectively and consistently reduce the response
of many types of structural systems to various types of earthquake excitations.
- Seismic Damage Control with Passive Energy Devices: A Case Study – R. McNamara
This paper presents a theoretical case study of the effectiveness of supplemental passive damping to
reduce structural response to seismic excitation. A six story special moment resistant reinforced
concrete frame is studied with and without the aid of supplemental dampers. Response predictions
are presented for each case. Fluid dampers proved to be a very cost effective way to significantly
reduce the seismic response of the building investigated. Preliminary cost estimates indicate that
positive damage control can be economically achieved.
- Seismic Isolation of Bridges (Unpublished Paper) – M. Constantinou
This unpublished paper by Dr. Michael Constaninou describes the seismic protection of a steel
multi-girder highway bridge. Three types of base isolators are included; high damping rubber,
lead-rubber and Friction Pendulum. The effect of added viscous damping is also investigated, and
is found to greatly enhance the performance of the isolators, even though the dampers required are
rather small. This classic paper is hand written by Dr. Constantinou and includes his calculations
and his sketches of the bridge, isolation devices and dampers.
- Seismic Response of Structures with Supplemental Damping – M. Constantinou, M. Symans
This paper presents a review of supplemental damping devices used for the control of the seismic
response of structures. The mechanical properties of these devices are discussed and considerations
in the design of energy absorbing systems are presented. Conventional structures passively resist
earthquakes through a combination of strength, deformability and energy absorption. They have
very little damping, so elastic energy absorption is small. Strong earthquakes deform these
structures well beyond their elastic limit through localized plastic hinging, which results in
increased flexibility and energy dissipation. Most of the earthquake energy is absorbed by the
structure through localized damage of the lateral force resisting system. This is somewhat of a
paradox in that the effects of earthquakes (i.e. structural damage) are counteracted by allowing
structural damage. Structural performance can be greatly improved if a large portion of the input
energy can be absorbed, not by the structure itself, but by some type of supplemental device. This
paper describes a number of ways to do this, including friction devices, yielding metal systems,
elastomeric viscoelastic dampers and fluid viscous dampers.
- Selected Production History High Capacity Taylor Devices Dampers and Energy Dissipators
This description of projects using Taylor Viscous Dampers is dated 1996 and includes only projects
up to that time. Since then we have provided dampers for over 300 structures throughout the world.
For the latest Project List send us a request. Go to our web site, www.taylordevices.com.
- Semi-Active Fluid Viscous Dampers for Seismic Response Control –
M. Symans, M. Constantinou, D. Taylor, K. Garnjost
The addition of passive damping to a structure greatly increases its earthquake resistance. It is
possible to get further increase through an active or semi-active control system for the dampers.
Semi-active damping is preferred due to low external power requirements and fail-safe operation.
This paper describes the history of the successful use of semi-active fluidic control devices in
military applications and how this technology has been adapted to earthquake hazard mitigation.
Testing of a semi-active continuously adjustable damping device through fluid orificing is
described. Mathematical models of the behavior of the device are also presented.
- Destruction Caused by the Quasi-Resonance Effects Observed in the Loma Prieta
Earthquake On October 17, 1989
This paper describes the widespread destruction caused by the Loma Prieta earthquake in the San
Francisco Bay Area. It deals extensively with some of the worst damage, which was the
destruction of huge circuit breakers. The article discusses how the repetitive nature of the seismic
input excited resonance in many structures.
- Test Methodology and Procedures for Fluid Viscous Dampers used in Structures to Dissipate
Seismic Energy – D. Taylor, M. Constantinou
Taylor Devices, Inc. has manufactured damping devices since 1955. Until 1990 most applications
were military, using dampers to attenuate weapons effects. Until recently, information on these
applications and the associated damper designs has not been public due to security restrictions.
Most of these restrictions have now been relaxed and much of this damping technology is now
available to the structural engineering community. Taylor Devices can now provide compact fluid
viscous dampers in the 100 kip to 2,000 kip output range that greatly reduces earthquake response
of structures. This paper describes how the military has been testing shock mitigation dampers for
many years and how this type of testing can apply to the large dampers required for seismic
protection of structures.
- Testing Procedures for High Output Fluid Viscous Dampers used in Structures to Dissipate
Seismic Energy – D. Taylor, M. Constantinou
This paper describes the dynamic testing of a 320 kip viscous damper using both sinusoidal
excitation and a drop test machine. Correlation was excellent, showing that drop testing can be
used to test very large dampers.
- University at Buffalo – Taisei Corporation Research Project on Bridge Seismic Isolation
Systems – M. Constantinou, S. Fuji, P. Tsopelas, S. Okamoto
This paper describes the first part of a project to produce a class of passive sliding seismic isolation
systems for bridges. This includes experimental verification of the systems by large scale shake
table testing, analytical techniques for interpretation of the experimental results, and design
procedures for sliding bridge isolation systems. A quarter length scale bridge model was tested on
a shake table. Restoring force was provided by various means. First, spherically shaped sliding
bearings (known as FPS bearings) were used to provide restoring and frictional forces within a
compact unit. Next, flat sliding bearings were combined with various devices placed between the
deck and the pier to provide restoring force and additional energy dissipation capacity. These
devices were in the form of: a) arc-shaped rubber elements between a moving central rod and a
cylindrical housing, b) wire rope springs, c) fluid spring-damper devices and d) fluid viscous
- Questions Concerning Seismic Isolation of Hospitals – D. Taylor
This discussion describes why base isolation is effective for seismic protection of hospitals and how
the addition of damping works to maximize its effectiveness.
- Technical Report NCEER-92-0032, Experimental and Analytical Investigation of Seismic
Response of Structures with Supplemental Fluid Viscous Dampers – M. Constantinou,
This 206 page report presents the results of an extensive study on fluid viscous dampers. A series
of component tests with various dynamic inputs was performed to determine the mechanical
characteristics and frequency dependencies of the dampers. In addition, temperature dependencies
were evaluated by varying the ambient temperature of the damper during component testing. Based
on these component tests, a mathematical model was developed to describe the macroscopic
behavior of the damper. Earthquake simulation tests were then performed on one story and three
story steel structures both with and without dampers. The addition of supplemental dampers
significantly reduced the response of the structure for both interstory drift and shear forces. The
experimental responses correlated well with analytical predictions.
- Technical Report NCEER-94-0014, Experimental and Analytical Study of a System
Consisting of Sliding Bearings and Fluid Restoring Force/Damping Devices –
P. Tsopelas, M. Constantinou
This report describes an experimental study of the behavior of a bridge seismic sliding isolation
system consisting of flat sliding bearings and fluid restoring force/damping devices. Earthquake
simulator tests were performed on a model bridge structure both with isolators and without. The
experimental results demonstrate a marked increase of the capacity of the isolated bridge to
withstand earthquake forces. Analytical techniques are used to predict the dynamic response of the
system and the obtained results are in very good agreement with the experimental results.
- Technical Report NCEER-94-0020, Study of Seismic Isolation Systems for Computer Floors –
V. Lambrou, M. Constantinou
This report describes the development and testing of a computer floor seismic isolation systems
which uses existing devices developed for the seismic isolation of buildings and shock isolation of
military equipment. A computer floor system with raised floor and a generic slender equipment
cabinet was constructed. It was isolated by spherically shaped sliding bearings and was highly
damped either by utilizing high friction in the bearings or by installing fluid viscous dampers. The
spherically shaped bearings provided the simplest means of achieving long period in the isolation
system under low gravity load. The isolation system prevented rocking of the cabinet on top of the
isolated floor and substantially reduced its acceleration response in comparison to that of a
conventional computer floor. An analytical study was also conducted in order to extend the results
to a range of parameters which could not be tested.
- Application of Fluid Viscous Dampers to Earthquake Resistant Design – M. Constantinou
This article summarizes the extensive viscous dampers investigation performed by NCEER at State
University of New York, Buffalo Campus. This included computer modeling of both the dampers
and complete isolated systems, along with shake table testing and correlation of results. The article
also describes a very large damper projects; dampers + base isolation for a set of five hospital
buildings near San Bernardino, CA.
- Martin Marietta Fluid Viscous Damper Study, Oak Ridge Plant – C. Winters
This non-published report describes the seismic analysis of a building at Oak Ridge, TN. It shows
that the addition of viscous dampers to this structure provides adequate seismic protection.
- Fear of Trembling – The Economist Brochure
This article describes the effects of both the Kobe earthquake and the Northridge earthquake in
detail, including technical and economic details. It also discusses building codes and practices and
what is being done around the world to lessen the risk of severe seismic damage.
- Seismic Rehabilitation of a Historic Non-Ductile Soft Story Concrete Structure using Fluid
Viscous Damper – K. Miyamoto, R. Scholl
Hotel Woodland is one of the first structures in North America to be seismically retrofitted using
viscous dampers. This four story 1927 vintage Historical Landmark reinforced concrete building is
located in Woodland, California. It was essential to improve the earthquake response performance
of the building and minimize cost while maintaining the historical appearance of the building. This
paper presents the processes and decisions regarding retrofit criteria and design procedure for
earthquake demand, building response performance, historical interests, and economic
- Viscous Damping for Base Isolated Structures – S. Hussain, D. Lee, E. Retamal
Seismic Base Isolation can use elastomeric pads, sliding plates or inverted pendulums. Each
method can include an energy dissipation means, but only as some kind of hysteretic damping.
Hysteretic damping has limitations in terms of energy absorption and may tend to excite higher
modes in some cases. It’s possible to avoid these problems with viscous dampers. Viscous
damping adds energy dissipation through loads that are 90o out of phase with bending and shear
loads so even with damping levels as high as 40% of critical adverse side effects tend to be
minimal. This paper presents basic theory of viscous damping and also describes a sample project.
Viscous dampers being built for the new San Bernardino Medical Center reduce both deflections
and loads by 50% compared with high damping elastomer base isolation bearings by themselves.
- Testing Procedures for High Output Fluid Viscous Dampers used in Building and Bridge
Structures to Dissipate Seismic Energy – D. Taylor, M. Constantinou
This paper describes the use of viscous dampers to protect structures from seismic damage and also
describes the development of test procedures for very large viscous dampers.
- Damping Devices for Earthquake Protection of Residential Structures – R. Langenbach
A set of four viscous dampers plus a unique pile foundation system provides seismic protection for
a wood frame house in Oakland, CA. This paper describes both the technical aspects of this design
and the costs.
- Seismic Evaluation and Retrofitting of U.S. Long-Span Suspension Bridges –
ASCE Subcommittee on Seismic Performance of Bridges
This paper is a first attempt to raise issues about the seismic evaluation and retrofitting of longspan
suspension bridges in the United States. The issues discussed in this paper deal seismic
hazards and risks; performance and design criteria; ground motions; geotechnical engineering,
substructure mathematical modeling, and soil structure interaction (SSI); actual conditions of
structural components; superstructure mathematical modeling; ambient vibration testing; analysis of
superstructure; suspension bridge component vulnerabilities; instrumentation and monitoring;
laboratory testing; retrofitting; and the effects of limited funding and time constraints.
- Energy Dissipation Devices in Bridges using Hydraulic Dampers –
E. Delis, R. Malla, M. Madani, K. Thompson
Specially designed energy dissipation systems are well known for improving seismic performance
of structures by absorbing earthquake induced energy. In this paper, the use of linear and nonlinear
hydraulic dampers is investigated in a bridge application. A two-span, skewed, cast-in-place
prestressed concrete bridge with an outrigger bent is examined. The bridge is located in a highly
seismic area of Southern California. It is observed that dampers alleviate the torsional movement
and reduce the transverse and longitudinal movements of the superstructure.
- Sample Technical Specifications for Viscous Damping Devices
This sample specification can be used for a variety of viscous dampers. It covers material,
performance, testing and inspection.
- Fluid Dampers for Applications of Seismic Energy Dissipation and Seismic Isolation –
D. Taylor, M. Constantinou
SUNY Buffalo has conducted extensive evaluation of fluid viscous dampers including development
of an analytical model of the damper, computational models of structures including dampers and a
number of experimental verifications. This paper describes this program, along with a history of
viscous dampers and a description of some projects that use them.
- Pre-Qualification Testing of Viscous Dampers for the Golden Gate Bridge Seismic
This report presents the results of the testing of a viscous damping device provided to the
Earthquake Engineering Research Center (EERC) of the University of California at Berkeley for
pre-qualification testing as part of the seismic rehabilitation of the Golden Gate Bridge. In all, four
different viscous dampers from four different manufacturers were tested in the prequalification
program. This report presents the test results for the damper denoted Damper C. The test results
for the other three dampers, Dampers A, B, and D, are presented in separate reports. Conclusions
were that Damper C performed consistently and well throughout the entire testing/pre-qualification
program. This report also includes a complete specification for production dampers for this project.
- Fluid Viscous Damping as an Alternative to Base Isolation – G. Haskell, D. Lee
Base isolation of large structures has proven to be an effective way to attenuate seismic excitation.
However it can be costly, and can also involve major building modification. It is now possible to
attain a comparable degree of earthquake mitigation with fluid viscous dampers located throughout
a structure, without having to isolate the building. This paper describes several techniques for
doing this, provides analytical back-up and describes several applications of this technology.
- Electrorheological Damper with Annular Ducts for Seismic Protection Applications –
N. Makris, S. Burton, D. Taylor
This paper presents the design, analysis, testing and modeling of an electrorheological (ER) fluid
damper developed for vibration and seismic protection of civil structures. The damper consists of a
main cylinder and a piston rod that pushes an ER fluid through a stationary annular duct. The basic
equations that describe the fluid flow across an annular duct are derived. Experimental results on
the damper response with and without the presence of electric field are presented. A combination
of a simple phenomenological model and a neural network is proposed as a practical tool to
approximate the nonlinear and velocity dependent damper response.
- Design of Steel Pyramid using Fluid Viscous Dampers with Moment Frames –
K. Miyamoto, R. Scholl
The Eleven story 450,000 ft2 pyramid shaped office building described in this article was one of the
first new buildings in the United States to use Seismic Dampers. This National Headquarters for a
financial institution is located in West Sacramento, CA. The basic lateral force resisting system of
the building consists of steel moment frames. In addition, approximately 15% of critical damping
was provided using Fluid Viscous Dampers (FVD) in order to reduce displacement and
acceleration. The steel moment frames were designed to remain well below the yield strength, and
the story drift ratio was limited to 0.005 to protect the welded moment connections for the Design
Basis Earthquake (DBE). Earthquake performance, cost effectiveness, and architectural
requirements were the primary concerns in designing this building.
- Development and Testing of an Electronically Controlled Shock and Vibration Damper
having an Electrorheological Fluid Medium – D. Taylor, N. Makris
An electrorheological (ER) fluid has been developed comprised of zeolite particles suspended in
silicone oil. Testing of this fluid in a damper of 1,000 lbs. nominal output force rating has
demonstrated the ability to control damper output with internal pressures above 500 psi and control
power requirements of less than one watt. The damper control valve is a simple ER duct, with no
moving parts, requiring only that a voltage potential exists across the duct's cross section to activate
the ER material, and thus cause the material to exhibit plastic behavior. All tests were successful,
with no degradation of the damper or ER material occurring over large numbers of activation cycles
or with time.
- Arrowhead Regional Medical Center – An Advertising Supplement to F. W. Dodge,
A Division of the McGraw-Hill Companies, Inc.
This article describes every aspect of the design and construction of the Arrowhead Regional
Medical Center, including the use of base isolators and viscous dampers to insure continuous
operation even after a major seismic event. The article even includes many of the financial aspects
of this huge project.
- Seismic Testing of a Building Structure with a Semi-Active Fluid Damper Control System –
M. Symans, M. Constantinou
This paper describes shaking table tests of a multi-story scale model building structure subjected to
seismic excitation and controlled by a semi active fluid damper control system. The semi active
dampers were installed in the lateral bracing of the structure and the mechanical properties of the
dampers were modified according to control algorithms which utilized the measured response of the
structure. A simplified time delay compensation method was developed to account for delays
within the control system. The results of shaking table tests are presented and interpreted and
analytical predictions are shown to compare reasonably well with the experimental results. These
tests included an undamped system, passive damping, and semi-active damping. Both the purely
passive damper system and the semi-active system significantly reduced seismic response.
- Testing and Modeling of an Improved Damper Configuration for Stiff Structural Systems –
M. Constantinou, P. Tsopelas, W. Hammel
This report describes a toggle brace damper system that adds significant damping to stiff structures,
like reinforced concrete shear wall buildings. It is generally recognized that these stiff structural
systems, such as reinforced concrete shear walls and steel braced dual systems, are characterized by
small drifts and small relative velocities that make the implementation of seismic energy dissipation
devices difficult. This report presents a study on a toggle brace damper system that magnifies the
damper displacement and reduces the required damper force to produce the desired damping. The
reports presents the concept, describes the theoretical treatment, and includes an experimental study
with cyclic and shake table testing of a model structure along with procedures for response history
and simplified analysis.
- Applications of Hermetically Sealed Fluid Dampers for Low Level, Wide Bandwidth
Vibration Isolation – A. Klembczyk, M. Moser
Vibration isolation of sensitive components like high resolution cameras requires extremely low
friction in the isolator system. Hydraulic dampers for these systems must be leak-free, which
equates to relatively high friction seals. There is always a trade-off between allowable leakage and
allowable friction in this type of application. This paper describes the isolation performance of a
new hermetically sealed damper with essentially zero friction. It contains both an analytical
representation of damper performance and dynamic test results.
- Developing and Testing of an Improved Fluid Damper Configuration for Structures having
High Rigidity – D. Taylor, M. Constantinou
Structures with high rigidity experience relatively small deflections and interstructural velocities
under seismic shock. This means that conventional energy dissipation devices may not be feasible
or cost effective. An improved damper configuration has been investigated, utilizing a toggle
mechanism to magnify internal structural deflections. This provides a more effective way to add
damping to a stiff structure. Experimental results were obtained from a 32,000 lb. test structure
utilizing two fluid dampers and two toggle brace elements. Test inputs included around eighty
individual earthquake transients, varying both in wave form and intensity. The results
demonstrated the ability of the toggle mechanism to magnify displacements significantly. The
toggle brace damping system appears to be an excellent solution to the addition of supplemental
damping devices to rigid structures of all types. Advantages include relatively low damper cost, a
simple bracing element design, and low installation cost.
- SEAOC Energy Dissipation Committee Appendix A: Guidelines for Buildings using Passive
Energy Dissipation Systems
This set of provisions provides minimum design requirements for the incorporation of passive
energy dissipation devices in buildings. Energy dissipation devices (also termed damping devices)
reduce global and interstory seismic displacement response of structural systems, but may either
increase or decrease seismic stresses and accelerations within structural systems. They provide a
controlled increase in structural damping, and may also result in an increase in structural stiffness
or change in participating mass. Passive energy dissipation systems do not require active control by
electrical, pneumatic or hydraulic systems. Buildings designed in conformance with these
provisions must also be designed in accordance with all other applicable provisions of the Uniform
Building Code, except as specifically defined in this appendix. Design must consider the combined
behavior of all elements of both the Lateral Force Resisting System (LFRS) and the Energy
Dissipation System (EDS). Energy dissipation devices must not form part of the gravity load -
- Taylor Fluid Viscous Dampers Protect Against Earthquake Damage – Here’s how it Works
This article from Bridge Builder magazine shows how Taylor Devices dampers reduce seismic
response of bridges.
- Experimental Study of Bridge Elastomeric and other Isolation and Energy Dissipation
Systems with Emphasis on Uplift Prevention and High Velocity Near-Source Seismic
Excitation – M. Constantinou, A. Kasalanati
A series of shake table tests on an isolated bridge model included low and high damping
elastomeric isolation systems, and low damping elastomeric systems with added linear and
nonlinear viscous dampers. Each of these configurations could withstand much stronger seismic
excitations than the non-isolated configurations. A set of low intensity tests was conducted to form
a basis for comparison with the non-isolated configurations and also to test the effectiveness of
these systems under low intensity excitation. The results of these tests are presented, followed by a
discussion of the effects of scragging, the benefits of seismic isolation, and the significance of
damping, the importance of added damping in near source seismic excitation and on the benefits
and drawbacks of using nonlinear viscous damping.
- Buildings: Design for Damping – D. Taylor
The end of the Cold War in 1990 heralded a restructuring period for the American military and
defense industry. In the civil engineering field, high capacity fluid dampers have transitioned from
defense related structures to commercial applications on buildings and bridges subjected to seismic
and/or wind storm inputs. Because fluid damping technology was proven thoroughly reliable and
robust through decades of Cold War usage, implementation on commercial structures has taken
place very quickly. This paper provides a broad overview as well as a guide to implementation;
with specific case studies for four of the more than 300 major buildings and bridges equipped with
fluid dampers by Taylor Devices, Inc., a defense contractor from the Cold War years.
- Structural Control of Dynamic Blast Loading using Fluid Viscous Dampers –
K. Miyamoto, D. Taylor
This paper evaluates the effectiveness of Fluid Viscous Dampers to reduce blast loading responses
in steel buildings. The paper addresses the following issues: (1) development of a blast loading
time history from a 3,000 pound explosive charge, (2) characteristics and historical applications of
fluid Viscous Dampers for blast and weapon effects, and (3) blast effects and performance
comparisons of a conventional steel building frame with and without dampers, and a conventional
concrete shear wall building. Simulation results indicate that Fluid Viscous Dampers provide a
cost effective way to greatly improve the performance of steel building frames under blast loading.
- Viscous-Damper with Motion Amplification Device for High Rise Building Applications –
R. McNamara, C.D. Huang, V. Wan
Adding damping by the use of various damping devices has become an accepted method to reduce
wind induced vibrations in tall buildings. An interesting example of a 39 story office tower is
presented where large projected accelerations are the result of vortex shedding of an adjacent
existing 52-story building. Viscous dampers and a toggle brace type motion amplification system
are used to suppress the anticipated accelerations. A description of the damping system and its
analytical simulation are discussed. This paper includes a nonlinear analysis of the tower, with time
history forcing functions derived from wind tunnel testing. Cost data for the damper system is also
- Test Report for 50 Tonne Force Viscous Damping Devices
(Taylor Devices Part Number 67DP-16394-01 – Test Report 00/2/15)
This test report describes the dynamic testing under sinusoidal excitation of a large viscous damper.
- Fluid Lock-up Devices – A Robust means to Control Multiple Mass Structural Systems
Subjected to Seismic or Wind Inputs – D. Taylor
Fluid Lock-up Devices have recently become popular for passive control of large structures
subjected to earthquake or wind storm effects. The Lock-up Device, a variation of the Fluid
Viscous Damper, allows unrestricted motion at low translational speeds. When a transient event
occurs the Lock-up Device activates and forms a rigid connection. After the transient event the
Lock-up Device reverts to low force output, permitting structural sections to thermally expand or
contract without added stress. The operation of the device is completely passive. It enables
multi-mass structures to be dynamically braced without resorting to the cost and complexity of an
active actuator system.
- A Numerical Investigation of Combined Shock and Vibration Isolation through the Semi-
Active Control of Magnetorheological Fluid Damper in Parallel with an Air Spring –
M. Mosher, T. Tanner
Combining shock and vibration isolation into a single isolation mount is investigated numerically
through the use of the Bouc-Wen model of a magnetorheological fluid damper in parallel with an
air spring. The stability and dissipative capabilities of the Bouc-Wen model are proven
mathematically. The response characteristic of this hybrid isolator to shock and vibration inputs is
explored. The advantages of combining shock and vibration isolation into a single package is
discussed. It is possible, using this technique, for a single device to perform equally well as a shock
and a vibration isolator.
- Structural Control of a Building using a Tuned Mass with Integral Hermetically Sealed,
Frictionless Hydraulic Dampers – B. Breukelman, A. Klembczyk
Structural control of large buildings using tuned mass damper systems has gained wide acceptance
in recent years. Significant structural performance improvements during wind storms have been
realized using both active and passive systems. Disadvantages of employing active systems include
high engineering and implementation costs, high maintenance costs, unnecessary system
complexities, and the requirement for a continuous and non-interrupted power supply. A design for
a passive tuned mass damper system is presented with analytical simulations and component test
results. These demonstrate the effectiveness of using a tuned mass in conjunction with a
maintenance free, hydraulic damper, having frictionless flexural seals to successfully attenuate the
response of a high rise building subject to severe wind inputs.
- Virtual Base Isolation by Building Softening with Drift Control Provided by Fluid Viscous
Dampers – M. Gemmill, K. Lindorfer, K. Miyamoto
The paper describes “virtual isolation” for buildings with one or more soft stories. Using the 1999
SEAOC Blue Book (SEAOC, 1999) recommendations for passive energy dissipation, the building's
Lateral Force Resisting System (LFRS) is designed for strength requirements only, resulting in a
relatively flexible LFRS, while Fluid Viscous Dampers (FVD) are incorporated to limit story drifts
to acceptable levels. There are many benefits to this "virtual isolation" system. With the
elimination of the maximum drift requirements, the moment frames are substantially lighter than a
traditionally framed building, thus lowering the structural steel cost of the LFRS. The long period
structure also produces significantly reduced forces in the foundation elements. Velocity and
displacement are reduced significantly through the use of the FVDs, which protects the sensitive
contents of the building. These benefits lead to a reduced response resulting in an enhanced
performance level during a major seismic event.
- Retrofit of a Metropolitan Midrise to Improve Torsional Response using Non-Linear Fluid
Viscous Dampers – M. Gemmill, K. Lindorfer, K. Miyamoto
In many metropolitan areas, midrise buildings are constructed adjacent to existing buildings, and
incorporate concrete shear walls to act as a barrier between the two buildings. The orientation of
these shear walls often causes severe torsional response within the building. The addition of a few
well placed nonlinear Fluid Viscous Dampers (FVD's) can significantly decrease the torsional
excitation, thereby increasing building performance. This paper describes the retrofit of an 18-story
steel frame building that exhibits severe torsional response from the "property line" condition at the
lower two stories. FVD's significantly reduce the displacement and acceleration of the second and
third floors of the building, where sensitive telecommunications equipment is being housed. They
reduce the demand and drift on the stories above with no additional construction required on these
floors. FVD's offer a very economical and effective means of mitigating undesirable building
response due to torsional irregularities. Their use would be effective in the retrofit of many existing
buildings with similar "property line" conditions.
- Viscous Damper Development and Future Trends – D. Lee, D. Taylor
Viscous dampers can protect structures against wind excitation, blast and earthquakes. Viscous
damper technology originated with military and aerospace applications. Approximately 20 years
ago it was found that the same fluid viscous dampers that protect missiles against nuclear attack and
guard submarines against near miss underwater explosions could also protect buildings, bridges and
other structures from destructive shock and vibration. This paper describes fluid damper
technology, analysis considerations, installation methods and development work in progress.
- Damper Retrofit of the London Millennium Footbridge-A Case Study in Biodynamic Design –
The Millennium Footbridge was opened to the public on June 10, 2000 - the first new bridge across
the River Thames in historic London in more than a century. Nearly 100,000 people used the new
bridge in its first day of operation. On June 12, 2000, the Millennium Bridge was ordered closed,
due to hazardous deck motions. Seemingly random pedestrian footfalls were causing resonance of
the bridge deck, with lateral accelerations measuring up to 0.25 g. The selected method of retrofit
was to add fluid damping to the bridge. This paper describes how this was done, including testing
of the bridge with groups of up to 2,000 people.
- U. S. Design of Structures with Damping Systems – K. Miyamoto, R. Hanson
This paper presents an earthquake design procedure and a case study of the Vacaville Police
Headquarters. The design goal for this essential facility was to provide immediate occupancy after a
475-year return seismic event. The project also required construction cost within typical code
conforming buildings. A combination of Special Moment Resisting Frames (SMRF) and Fluid
Viscous Dampers (FVDs) was used as the lateral force resistance system. This system, as described
by Gimmel, Lindorfer, and Miyamoto, (2002) results in cost efficiency and superior seismic
performance. The 2000 NEHRP (FEMA, 2000) guideline was used to design the project, since it is
considered to be a state-of-art procedure for seismic damping devices. This project was the first
structure in the United States to use this advanced procedure.
- History, Design and Applications of Fluid Dampers in Structural Engineering – D. Taylor
This paper is a shortened version of Paper 56, BUILDINGS: DESIGN FOR DAMPING – D.
TAYLOR. It shows four examples of recent structures which use dampers.
- Analysis, Optimization and Development of a Specialized Passive Shock Isolation System for
High Speed Planing Boat Seats – M. Mosher, A. Klembczyk
The Mk V Special Operations Craft (SOC) is used to carry Special Operations Forces (SOF) into
and out of combat operations. During operation, particularly during extended training missions, the
passengers and crew have reported numerous cases of musculoskeletal injuries from operation in
high sea states. This paper describes the analysis, development and operational testing of a highly
specialized, non-linear, passive shock isolated seat for this craft. Initial sea trial testing of the
isolation system resulted in positive operator feedback that correlated well with earlier field
measurements and also validated the analytical predictions.
- Seismic Rehabilitation of a Historic Concrete Structure with Fluid Visco-Elastic Dampers –
K. Miyamoto, L. M. Determan, A. Gilani, R. Hansen
This paper presents the nonlinear seismic analysis, development, and implementation of an
innovative seismic retrofit strategy for a six story nonductile reinforced concrete 145,000 square
foot historic building. Dynamic and nonlinear static analytical results verified that the building had
a weak soft story with inadequate post yield capacity and large torsional response. Hotel Stockton,
in Stockton, CA, is also torsionally irregular. The analysis indicated that the existing building was
not seismically adequate to withstand anticipated lateral forces generated by earthquake excitations
at the site. A "collapse prevention" performance upgrade for a 475-year return event was
developed. Nonlinear fluid viscous dampers were placed at the first story level to reduce the
seismic demand and obtain a more uniform response. Viscoelastic fluid viscous dampers were
strategically placed at one side of the building to reduce the torsional irregularity of the building.
This cost effective retrofit significantly improved the seismic performance of the building.
- Seismic Protection with Fluid Viscous Dampers for the Torre Mayor,
A 57-Story Office Tower in Mexico City, Mexico – D. Taylor, I. Katz
The new 57 story Torre Mayor Building is the now the dominant structure in the Mexico City
skyline. It is also the first tall building to utilize large Fluid Viscous Dampers as a primary means
of seismic energy dissipation. A total of 98 dampers are used, including 24 large dampers, each
rated at 570 tonnes of output force, located in the long walls of the building. The short walls utilize
74 smaller dampers, each rated at 280 tonnes of output force. The damping technology successfully
implemented for Torre Mayor is now being used on five other tall buildings, including three in the
USA, and two in Japan.
- Modular Tuned Mass Damper Units for the Spring Mountain Road Pedestrian Bridge –
D. Taylor, J. Metzger, D. Horne
Modern pedestrian bridges tend to be long and slender, usually causing relatively low frequency
primary modes of vibration. This type of structure can be excited to resonance by synchronized
crowd footfall. Added damping is often required to prevent excessive structural motions and
loadings. This paper describes the Modular Tuned Mass Dampers used to provide the required
added damping for the three Spring Mountain footbridges in Las Vegas.
- Taylor Devices Hermetic Dampers Description, Applications and Design – D. Taylor
This hermetically sealed damper was developed during the 1980's for use space platforms. NASA
and the U.S. military had experienced difficulties over the years with all types of oil filled products
in space. Conventional sliding surfaces that were sealed acceptably on earth proved unacceptable
for spacecraft use. Even the tiniest amount of fluid seepage past conventional seals turns into a
dense fog in a vacuum, contaminating optics and electronic systems. Taylor Devices' solution was
to develop a damper that uses a flexural seal - thus sealing by non-sliding methods. The seal itself
was a so called metal bellows made by laser welding thin discs of stainless steel into a bellows
configuration. This paper describes the design and construction of the Taylor Devices Hermetically
- Introduction to Shock and Vibration Isolation and Damping Systems – A. Klembczyk
This paper presents an introduction to shock and vibration isolation of complex structures and
mechanisms. It provides an outline of various ways to provide isolation, shock absorbing and
damping within a wide array of dynamic systems and structures. This paper presents key
definitions that are widely used within the shock and vibration community. Additionally, useful
formulae are presented that provide the user with an approach to typical problems. Finally, a
comparison of different types of shock isolators, shock absorbers and dampers compares their
advantages and disadvantages for use in the commercial, military, and aerospace sectors.
- Structural Control using Hybrid Spring-Damper Isolation with Integral Gapping Function –
D. Taylor, J. Metzger
The spring-damper isolators described in this paper were used on the world's largest cable stayed
bridge - the Sutong Bridge over China's Yangtze River, completed in 2008. The Sutong Bridge is
located north of Shanghai in China's Jiangsu Province at a site where catastrophic earthquakes,
typhoons, and ship impact are key design issues. The total length of the bridge is 4.7 miles, with a
.67 mile long center span. The tall support towers of this bridge and the long support cables create
long period motions along the primary axis of the bridge. The need to accommodate thermal
expansion and contraction of the deck axially means that extensive motion can occur in this
direction. The configuration of the bridge permits large axial motion of the suspended deck during
earthquakes, typhoons, and synchronized truck/car braking loads such as would occur during a
mass vehicular accident on the bridge. During dynamic earthquake loading, the long period of the
suspended deck provides inherent isolation, albeit essentially undamped. Analysis indicated that
added viscous damping would reduce deck motions substantially. During other events like
typhoons and vehicle loading, analysis determined that the most cost-effective solution was to
incorporate a snubbing type spring element that would only engage (become active) when the
damper was approaching its end of travel in either extension or compression. The spring-dampers
on this bridge have only damping forces for roughly 85% of the available displacement from the
neutral (center of travel) position. Beyond this travel the spring element engage and a combined
response of spring plus damper forces results. Essentially, the spring elements are "gapped"
through all but approximately the last 15% of the damper stroke in either direction.
- Simulation, Development and Field Measurement Validation of an Isolation System for a New
Electronics Cabinet in the Space Shuttle Launch Environment within the Mobile Launch
Platform – M. Mosher, A. Klembczyk
This paper describes the dynamic analysis of an isolator system for the cabinet-mounted low
voltage power switchgear in the Space Shuttle Mobile Launch Platform (MLP). The addition of
electronic sensing and control components to this cabinet combined with the harsh vibration
environment experienced during a Shuttle launch necessitated a six degree of freedom isolation
system to prevent the spurious tripping of breakers. An added benefit of the isolation system is that
it provides vibration isolation during the Shuttle’s approximately three mile journey between the
Vehicle Assembly Building (VAB) and either of its two launch pads. The isolation system was
designed, built, and integrated within the MLP. Broadband dynamic measurements were made
during an actual Shuttle launch to verify the effectiveness of the isolation system and to validate the
predictions of the analysis. Measurements made during the launch of STS-115 on September 9,
2006, affirmed the effectiveness of the isolators and validated the predicted performance of the
- Energy Management Utilizing the Hydraulic Shock Absorber – D. Taylor
The advent of high speed equipment and machinery has brought with it numerous problems
associated with slowing and stopping masses of various forms. The hydraulic shock absorber has
proven to be one of the most satisfactory means of solving these problems, yet the shock absorber
still remains as one of the least understood fluid power components. This paper presents design
constraints, design parameters and a description of how to use shock absorbers into a system for the
purpose of dissipating kinetic energy. Information is presented in both qualitative and functional
equation format to enable the reader to grasp the subjective aspects of shock absorber usage which
go beyond normal mathematical constraints.
- Experience and Practical Considerations in the Design of Viscous Dampers –
P. Duflot, D. Taylor
This paper describes how viscous dampers work, and how they significantly reduce seismic
excitation in structures.
- Fluid Viscous Dampers: An Effective Way to Suppress Pedestrian-Induced Motions in
Footbridges – P. Duflot, D. Taylor
Fluid viscous dampers have found commercial applications on buildings and bridges subject to
seismic and/or wind storm inputs. They are now being used as well on footbridges to suppress
undesirable pedestrian induced vibrations. This paper provides a brief overview of fluid damping
technology with specific case studies for pedestrian bridges now equipped with fluid viscous
dampers. These viscous dampers are used to suppress the feedback between the pedestrians and the
bridge and/or wind induced vibrations. On-site tests show that fluid viscous dampers provide
significant gains in performance at relatively low cost.
- A Living or Smart Building: The Guangzhou Tower – G. Hart, A. Jain, C.G. Ekwueme
This paper presents the evolution of the structural design of one of the tallest structures in the
world. The architectural design was developed by Mehrdad Yazdani at Cannon Design Group. The
basic architectural vision of the Guangzhou Tower is three twisting interconnected legs. The
architectural plan at each level of the tower rotates and twists. The basic structural vision here is of
a Living Structure that can be adapted and improved from a structural engineering perspective as
new high-tech products become available, as our understanding of the forces of nature improves
using ground and aerial instrumentation and as we improve the accuracy of our structural modeling
to estimate structural response to wind and earthquake loading.
- Applicability of Seismic Protective Systems to High Tech Industrial Structures –
J.S. Hwang, Y.N. Huang, Y.H. Hung, J.C. Huang
This paper summarizes a feasibility study for implementing seismic protective systems into high
tech industrial structures in which costly vibration sensitive facilities are housed. Micro-vibration
control of an IC fab is essential for optimum yield of reliable chip products. This paper describes
the micro vibration analysis and measurement of a test structure before and after the incorporation
of Seismic Protective systems. Based on the study, it is found that the incorporation of viscous
dampers both enhances seismic safety and also minimizes the micro vibration of the structure.
Viscous damper seismic isolation is the most promising method to achieve the "fully operational"
seismic performance level of an IC fab.
- Full-Scale Shake Table Tests of 5-Story Steel Building with Various Dampers –
K. Kasai, H. Ito, Y. Ooki, T. Hikino, K. Kajiwara, S. Motoyui, H. Ozaki, M. Ishii
Realistic simulations of earthquake responses were conducted in March 2009 for a full-scale 5-story
building specimens with dampers using the E-Defense, the world’s largest three-dimensional shake
table. The building was tested repeatedly, inserting and replacing each of 4 damper types, steel
damper, oil damper, viscous damper and viscoelastic damper. This paper discusses the test method
and test results as well as details of the 5-story building specimen. Performance improvement by
the dampers is addressed for moderately tall buildings that constitute a major portion of the building
- Hold onto Your Seat – M. Burnett
This article appeared in Special Operations Technology magazine. It provides a very complete
explanation of the Taylor Devices isolated seat for the Navy, complete with many photos. The
article also includes the experiences of the seat occupants under high speed ocean travel.
- Mitigation of Military High Shock Transients for Shipboard Gyrocompass with Fiber Optic
Gyros (FOG) – J. Lahham, S. J. Ryan, D. J. Wigent, M. W. Mosher, A. Klembczyk
The Taylor Devices self-centering hexapod mount provides MIL-S-901D shock protection for the
Litton Marine Systems MK27F Attitude and Heading Reference System (AHRS). This new
Reference System satisfies stringent military shock and vibration requirements. Unlike Ring Laser
Gyro (RLG) which have low fragility levels (Max 50 g), the LN200 Fiber Optic Gyro Assembly
can be exposed to levels as high as 90 g. This paper addresses the shock transient mitigation for
shock requirements specified by MIL-S-901D. Comparisons between predicted and measured
response are provided for a single strut as well as the fully shock isolated platform. Analytical and
experimental results are presented to demonstrate the effectiveness of the MK27F Shock Absorber
basic design for MIL-S-901D LWSM and predicted response is also presented for the floating
platform Heavy Weight Shock Machine (HWSM).
- Shock Design of the MK 49 Ship’s Inertial Navigation System (SINS) –
J.R. Brazell, D.K. Bruce, G.T. Mayer
The Sperry Marine MK 49 Ship's Inertial Navigation System (SINS) is now in production for
marine surface and subsurface applications. This system has been selected as the standard NATO
SINS equipment and is the only marine inertial navigator which utilizes ring laser gyros. In order
to serve the NATO community, the system must withstand a variety of shock stimuli (STANAG
4141, STANAG 4142, BR3021, etc.). Sperry Marine has shock hardened the system enclosures
and developed a shock isolation system for the Inertial Measurement Unit (IMU) using tension
compression liquid spring/dampers in a hexapod configuration. This isolator assembly provides the
shock attenuation and precision angular alignment return ability that is needed to meet the above
specifications. This paper addresses the design process to shock harden the IMU and presents
- Base Isolation and Supplemental Damping Systems for Seismic Protection of Wood
Structures: Literature Review – M. Symans, W. Cofer, K. Fridley
This paper provides a literature review on the application of base isolation and supplemental
damping systems for seismic protection of wood structures. The review reveals that both
elastomeric bearings and sliding bearings have been considered for implementation within base
isolation systems of wood framed buildings. In addition, friction dampers, viscoelastic dampers,
hysteretic dampers, and fluid viscous dampers have been considered for implementation within the
framing of wood buildings. Although there are a number of impediments to the widespread
implementation of such advanced seismic protection systems, the reviewed literature clearly
demonstrates that advanced seismic protection systems offer promise for enabling light framed
wood structures to resist major earthquakes with minimal damage.
- Fluid Dampers for Seismic Protection of Woodframe Structures –
M. Symans, W. Cofer, Y. Du, K. Fridley
In the recent past a large number of steel framed buildings have used supplemental energy
dissipation systems to provide seismic protection. However, the application of such systems to
wood frame structures has been essentially non-existent except for a limited number of
experimental laboratory studies. This paper presents a numerical study of the application of fluid
dampers for seismic protection of wood framed structures. Such dampers dissipate energy via
orificing of a fluid. The seismic response of a wood framed shear wall with and without dampers is
evaluated via nonlinear finite element analyses. The results of the analyses demonstrate that the
dampers are capable of dissipating a large portion of the seismic input energy while simultaneously
relieving the inelastic energy dissipation demand on the shear wall.
- Seismic Performance of Light-Framed Wood Structures with Toggle Braced Fluid Dampers –
J. Shindel, M. Symans
In recent years, seismic damping systems have been employed in numerous steel and concrete
framed buildings. Such systems dissipate a significant portion of the seismic input energy, thereby
relieving the energy dissipation demand on the structural framing system and thus reducing
damage. As part of a NEESR project to develop a performance based approach to seismic design of
multi-story light framed wood structures, the application of damping systems to such structures has
been evaluated via seismic shaking table tests and numerical simulations. This paper focuses on the
results from shaking table tests of shear walls employing toggle braced fluid dampers. The results
demonstrate that toggle braced fluid dampers provide a significant increase in the seismic resistance
of the walls, allowing them to achieve high levels of performance when subjected to strong ground
- U.S. Code Development of Structures with Damping Systems – R. Hanson, K. Miyamoto
Damping devices are being increasingly used in both new and existing buildings in both United
States and Japan. This increased popularity has created a demand for design guidance and building
codes. This paper provides a summary of the code development activities for the 2003 NEHRP by
the Building Seismic Safety Council.
- Rehabilitation of a 1985 Steel Moment Frame Building – G. Haskell
A 1985 steel moment frame was seismically upgraded using passive energy dissipation, without
adding stiffness to the system. The design and analysis techniques for sizing the Velocity Braces
and their impact on the demand capacity ratios are reviewed in this paper. The original structure
was built in the San Francisco Bay Area in compliance with the 1985 Uniform Building Code
(UBC). The moment frame contains the classic pre-Northridge nonductile moment connection.
Nonlinear time history analysis was used to design a damper system that provides a significant
decrease in seismic response.
- Coupled Truss Walls with Damped Link Elements – A. Rahimian
A new structural concept is proposed for the seismic design of tall buildings. This system combines
the inherent stiffness and strength of a conventional truss system with the energy absorption
characteristic of supplemental damping elements. The damping elements are strategically placed to
form the linking elements of a coupled vertical truss system. While the force resistance system of
the truss wall is in parallel, the damped link beam is in series with the component of the truss
stiffness contributed to the coupled wall action. A series of time history dynamic studies gauged
the performance of the proposed concept and found the proposed damped link concept superior in
performance compared to the conventional approach.
- Experimental Study of RC Building Structures with Supplemental Viscous Dampers and
Lightly Reinforced Walls – H. Tsai, Shiang-Jung Wang et al
This paper describes an experimental evaluation of viscous dampers used to reduce seismic motion
in reinforced concrete moment-resisting building structures. Common practice in Taiwan is to use
lightly reinforced concrete exterior walls and interior partition walls, which not considered for their
contribution of stiffness and strength in the design process. As these additional walls greatly reduce
relative story displacement and velocity, it has been suspected that the effectiveness of
supplemental dampers would be very limited. However, the test results show that a new
displacement multiplying mechanism, the toggle brace damper system, is effective even with a
small relative story drift in the seismic response control of the structure. Dampers produce
significant force and displacement reduction in the moment-frame structures that were investigated.
- A Simple Method for the Design of Optimal Damper Configurations in MDOF Structures –
Existing methods for the design of optimal configurations of supplemental dampers are usually not
simple enough to be used routinely, and typically lead to different damper sizes at virtually every
story. This can be avoided with the Sequential Search Algorithm, which lets the designer control
the number of different damper sizes. In this paper, a simplification to the Sequential Search
Algorithm is developed. This Simplified Sequential Search Algorithm makes it easy for engineers
to deal with damper added structures. It was found that the efficiency of damper configurations
given by the proposed Simplified Sequential Search Algorithm is comparable to the efficiency of
damper configurations given by more sophisticated procedures. The applicability of the method is
limited to those cases where the response of the structure with added dampers remains linear.
- Optimized Damping Device Configuration Design of a Steel Frame Structure Based on
Building Performance Indices – W. Li, M. Tong, Y. Wu, G. Lee
Energy dissipation devices (EDDs) have been accepted as one of the viable strategies for enhancing
the seismic performance of building structures. However, current design provisions do not provide
guidelines for optimizing the EDD configurations. For many building structures an efficient
configuration of EDDs may provide considerable performance improvement. Similarly, an
optimized configuration may reduce the number of EDDs required to achieve a target performance
objective. In this paper an existing building with added linear viscous dampers is redesigned based
on different performance index optimization. The results indicate that the optimal device
configurations are highly related to the dynamic properties of the structure and its required
performance index. In one instance, where the cost is the major concern and a performance
requirement is placed on story drift limitation, the total device damping coefficient can be reduced
- Roof Isolation System to Reduce the Seismic Response of Buildings: A Preliminary
Assessment – R. Villaverde
A roof isolation system is proposed as a means to reduce the detrimental effect of earthquakes in
buildings. This roof isolation system entails the insertion of flexible laminated rubber bearings
between a building's roof and the columns that support it and the addition of viscous dampers
connected between the roof and the rest of the building. The properties and dimensions of the
rubber bearings and viscous dampers are selected in a way that makes the roof, bearings, and
dampers form a highly damped vibration absorber. Presented also is a comparative study with a
simple five story steel building under a strong earthquake ground motion that is carried out to
assess the effectiveness of the proposed system. In this comparative study, it is found that the roof
isolation scheme reduces the floor displacements and interstory drifts of the analyzed building by as
much as 83 percent. On the basis of these results and in view of its simplicity, it is concluded that
the proposed roof isolation system has the potential to become a practical and effective way to
reduce earthquake damage in buildings.
- Scissor-Jack Damper Energy Dissipation System – A. Sigaher, M. Constantinou
Installation of damping devices has been limited to diagonal or chevron brace configurations until
the recent development of the toggle brace. This configuration magnifies the effect of damping
devices, thus facilitating their use in stiff framing systems. This paper introduces the scissor jack
damper system that was developed as a variant of the toggle-brace damper system, with the added
advantage of compactness. The effectiveness of the scissor jack configuration is demonstrated
through testing of a large scale steel framed model structure on an earthquake simulator. Experiments
showed that despite the small size of the damping device considered, the scissor jack system
provided a significant amount of damping and substantially reduced the seismic response of the
tested structure. Response history and simplified analyses produce results that are consistent with
the experimental results.
- Seismic Protection System and its Economic Analysis of the Beijing High Rise Building Pangu
Plaza – Y. Chen, T. Cao, L. Ma, C. Iuo
Pangu Plaza, located at Beijing close to 2008 Olympic main stadium, is a 191 meter, 39-story steel
high rise building. It was analyzed under earthquake and wind loads with both Fluid Viscous
Dampers (FVD) and Buckling Restrained Braces (BRB or UBB) as the seismic protection system.
The complete seismic response on the horizontal and vertical directions showed that the Fluid
Viscous Dampers are highly effective to reduce the structural response, as well as the secondary
system response. A comparative analysis of structural seismic performance and economic effect
was considered, by the traditional method of increasing steel columns and beams size; by using
BRB’s and by using FVD’s to absorb the seismic energy. Structural response analysis showed that
using FVD’s to absorb the seismic energy made the structure satisfy the Chinese seismic design
code for the "rare" earthquake and also greatly improved the seismic performance. Economic
analysis showed that FVD’s were the most economic approach for both one-time direct investment
and long term maintenance.
- Application of Energy Dissipation Technology for Retrofitting Steel Structures with
Vulnerable Pre-Northridge Connections – O. Waqfi, R. Hamburger, R. Kanitkar
Prior to the 1994 Northridge earthquake, modern welded moment resisting steel frame structures
were regarded as highly resistant to earthquake induced damage and few engineers regarded
earthquake induced collapse of such structures as credible. This paradigm changed following the
1994 Northridge, California and 1995 Kobe, Japan earthquakes, creating a new class of potentially
hazardous structures. In response to this new information, the Federal Emergency Management
Agency retained a consortium of the Structural Engineers Association of California, the Applied
Technology Council and the California Universities for Research in Earthquake Engineering,
known as the SAC Joint Venture, to research the cause of the unexpected poor performance of these
buildings and develop recommended design criteria. The resulting FEAM-351 publication provides
performance based design criteria for the evaluation and upgrade of these structures. This paper
presents the application of the FEMA-351 criteria to the design of structural upgrades employing
energy dissipation technology to an existing 10-story steel structure. The East Bay Municipal
Utility District (EBMUD) administration building is nine stories tall, with three below grade
basement levels and a rooftop, mechanical penthouse. It was completed in 1991, employing the
standard vulnerable moment connections. Alternative upgrade strategies were investigated,
including modification of individual connections and application of energy dissipation criteria. The
latter approach, using viscous dampers, was selected.
- Shock Control of Bridges in China using Taylor Devices’ Fluid Viscous Dampers –
C. Yongqi, M. Liangzhel, C. Tiezhu, R. Schneider, C. Winters
Fluid Viscous Devices have been found to be a highly effective protection system for bridges.
Introduced to China in 1999, the Taylor Devices damper systems have been successfully installed
or will be installed in both large and super large bridges in China for protection from earthquake,
wind, vehicle and other vibration. Seventeen different bridge projects include the Sutong Yangtze
River Bridge, the longest cable stayed bridge in the world, the Nanjing 3rd Yangtze River Bridge,
the fifth longest suspension bridge in the world, and the Xihoumen across Sea Bridge, the second
longest suspension bridge in the world. The performance of the bridges and dampers have been
reported as "very good" during the May 12, 2008 Wenchuan earthquake. All of the dampers
produced have been subjected to rigorous static and dynamic testing, which show the dampers will
perform well for the next 50 years and possibly much longer.
- Use of Motion Amplification Devices and Fluid Dampers to Reduce the Wind Induced
Response of Tall Buildings – R. McNamara
Adding damping with various energy dissipating devices has become an accepted method to reduce
wind induced vibrations in tall buildings. An example of a 39-story office tower is presented where
large projected accelerations generated by the vortex shedding of an adjacent existing 52-story
building are reduced by a passive system composed of viscous dampers and a motion amplification
system. A description of the damping system and its analytical complexities are discussed.
Non-linear analysis of the tower, using time history forcing functions derived from the wind tunnel
is presented. Cost data for the damper system is also presented.
- Torsional Control of Two Adjacent Office Buildings using Viscous Dampers –
W. Gates, G. Hart, H. Mabramzadeh, S. Huang, D. Lee, L. Jacobson
Two adjacent wings of a three story office building in Southern California were found by analysis
to be excessively responsive in torsion under an earthquake on the near-by Newport-Inglewood
fault, some five miles from the site. The generous 4.5" seismic separation between the two office
building segments was found to be inadequate to prevent heavy pounding even in a moderate event,
having a high probability of occurrence at this location. A variety of structural retrofit schemes
were evaluated to mitigate the excessive torsional responses of the two building segments. These
included converting the perimeter gravity frames to moment resisting frames, adding diagonal
bracing to the perimeter frames, tying the two structures together at each floor level, and using
viscous dampers as attachments between the buildings. The best solution from a cost, schedule,
construction disruption, and earthquake performance standpoint, turned out to be joining the two
building segments with horizontally oriented viscous dampers at a single floor level. This paper
describes the analysis and retrofit solution that was used, and discusses the advantages and
disadvantages of the retrofit options studied.
- Validation of the 2000 NEHRP Provisions' Equivalent Lateral Force and Modal Analysis
Procedures for Buildings with Damping Systems – O. Ramirez, M. Constantinou,
A.Whittaker, C. Kircher, M. Johnson, C. Chrysostomouf
Equivalent lateral force and modal analysis procedures for yielding buildings with damping systems
were developed, validated, and incorporated in the 2000 NEHRP Provisions. Key to the
implementation of the procedures was the validation process that demonstrated the accuracy of the
proposed procedures. The procedures for implementing yielding, viscoelastic, linear viscous, and
nonlinear viscous dampers were tested using the results of nonlinear response history analysis on
sample three- and six story frames and were found to be robust.
- Wind Effects on Long Span Cable Stayed Bridges: Assessment and Validation –
N. Jones, E. Ozkan
The well known collapse of Tacoma Narrows Bridge in 1940 clearly identified the importance of
aeroelastic effects on long span bridge performance. Extensive research has been carried out since
then to better understand the effects of wind on long span bridges, producing various analytical
response prediction techniques. An example of the application of such techniques is presented.
However, due to challenges related with full scale measurements, these prediction techniques have
commonly been validated us
ing only wind tunnel experiments. Recent research has revolved
around the conduct of long term full scale measurements on a cable stayed bridge to compare actual
bridge performance with those of analytical predictions. In order to ensure the reliability of
predicted response, the input parameters, such as wind conditions at the site and modal properties of
the bridge are also calibrated using corresponding measured quantities. This paper summarizes
some of the preliminary results and outlines their implications.
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