N4TL INST- OF STAND 4 fECH RLC NIST Special Publication 832, Volume 1

A111D3 7aTm7

NIST

PUBLICATIONS

Earthquake Resistant Construction

I Using Base Isolation

[Shin kenchiku kozo gijutsu kenkyu iin-kai hokokusho ]

Earthquake Protection in Buildings

Through Base Isolation

United States Department of Commerce

Z Technology Administration

832 National Institute of Standards and Technology

V.1

1992
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NIST Special Publication 832, Volume 1 ^ |

Earthquake Resistant Construction

Using Base Isolation

[Shin kenchiku kozo gijutsu kenkyu iin-kai hokokusho ]

Earthquake Protection in Buildings

Through Base Isolation

Noel J. Raufaste, Editor

Building and Fire Research Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899

Originally Published by

Building Center of Japan

April 1992

U.S. Department of Commerce

Barbara Hackman Franklin, Secretary

Technology Administration

Robert M. White, Under Secretary for Technology

National Institute of Standards and Technology

John W. Lyons, Director
National Institute of Standards and Technology Special Publication 832, Volume 1 Natl. Inst. Stand. Technol. Spec. Publ. 832, Vol. 1, 161 pages (Apr. 1992)

CODEN: NSPUE2

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1992

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402-9325
ABSTRACT

This report is Volume One of a two volume series on passive energy dissipating

systems for buildings and other structures. This volume. Earthquake Protection in

Buildings Through Base Isolation, describes energy dissipation systems and reviews

their applications and effectiveness. These documents provide guidelines for

evaluating energy dissipating systems and a directory of the systems used in

buildings and other structures. The original reports in Japanese were published by

the Building Center of Japan under the sponsorship of the Japanese Ministry of

Construction (MOC). The MOC provided these reports to the National Institute of

Standards and Technology for their translation into English and for publication. The

subjects addressed in these reports include: the history and types of passive energy

dissipators; their applications, evaluations, and performance; and case histories of

these devices exposed to seismic loading.

KEYWORDS: active damper, base isolation; damping; devices; evaluation, passive

damper; performance, seismic; structures; wind loads.

Translated from Japanese by Amerind Publishing Co. Pvt. Ltd., New Delhi, under

contract to The National Technical Information Service, Department of Commerce.

iii-

CONTENTS

FOREWORD vii

PREFACE ix

OUTLINE OF THIS REPORT ' xxix

CHAPTER 1. AIMS AND OBJECTIVES OF SURVEY 1

CHAPTER 2. RESPONSE-CONTROL STRUCTURES 8

2.1. Terminology i s 8

2.1.1. Earlier terminology 8

2.1.2. Terminology used in this report 10

2.2. Classification and Characteristics of Response-Control

Structures 10

2.2.1. Classification , 10

2.2.2. Classification according to the basic principles of dynamics 18

2.2.3 Classification according to the method of

implementation 24

2.2.4. Classification according to the Position of Dampers ' 26

2.3. Examples of Proposals for Response-control Sructures and

Actual Constructions 26

2.3.1. Examples of historical importance in the Japanese

construction industry 26

r 2.3.2. Examples of response-control structures 52

2.3.3. Cases approved by the Ministry of Construction 63

2.3.4. Trends in other fields 63

- V-
CHAPTER 3. POSSIBLE APPLICATIONS OF RESPONSE-CONTROL

STRUCTURES 65

3.1. Improvement in Building Design by Using Response-control

Techniques 65

3.1.L Areas of Application 65

3.1.2. External turbulence as objectives of response-control 65

3.1.3. Improvement in the quality of design 66

3.2. Applications of this Technique 68

CHAPTER 4. VARIOUS ASPECTS OF RESPONSE-CONTROL

STRUCTURES 70

4.1. Topics for Future Technical Development 70

4.2. Suggestions for the Future 79

CHAPTER 5. EVALUATION OF EFFECTIVENESS OF RESPONSE-CONTROL AND BASE ISOLATION TECHNIQUES 81

5.1. Points for Effectiveness Evaluation 82

5.2. Evaluation of Safety . 88

CHAPTER 6. SUMMARY . 98

APPENDIX 1. VARIABILITY OF THE PERFORMANCE OF RESPONSECONTROL STRUCTURES 100

APPENDIX 2. EXAMPLES OF RESPONSE-CONTROL AGAINST WIND 103

APPENDIX 3. BIBLIOGRAPHY 113

- vi-
FOREWORD

This is one volume of a two volume series on energy dissipating devices for

buildings and other structures. Volume 1, Earthquake Protection in Buildings

through Base Isolation, describes energy dissipating devices, reviews their use for

application, and discusses their effectiveness. Volume 2, Survey Report on Framing

of the Guidelines for Technological Development of Base isolation Systems

Buildings, addresses the performance of these devices and provides examples of

buildings installed with such devices and case studies. The two-volume reports

were produced by the Building Center of Japan under sponsorship of the Japanese

Ministry of Construction (MOC) to describe the state-of-the-art of energy dissipating

devices and to review their use in mitigating damages from earthquakes.

These reports were made available to the National Institute of Standards and

Technology (NIST) for translation into English and for publication through the

Panel on Wind and Seismic Effects. The Panel is one of 16 comprising the U.S.-Japan

Program in Natural Resources (UJNR). The Panel, composed of U.S. and Japanese

agencies participating with representatives of private sector organizations, develops

and exchanges technologies aimed at reducing damages from high winds,

earthquakes, storm surge, and tsunamis. NIST provides the chairman and

secretariat of the U.S.-side Panel on Wind and Seismic Effects; the Public Works

Research Institute, MOC, provides the Japan-side chairman and secretariat.

These volumes were translated under contract by the National Technical

Information Service (NTIS). The English translations convey the technical contents

of the two reports; no further efforts were made to editorialize the translated

manuscripts.

The U.S.-side Panel is indebted to the Japanese-side Panel for sharing useful design

and construction information about an emerging technology for mitigating damages

to buildings and other structures from earthquakes and high winds. The U.S.-side

also is appreciative of the efforts of Mr. Tatsuo Murota, Director, Structural

Engineering Department of the Building Research Institute (BRI), MOC, and his BRI

staff for reviewing the English translated versions. Finally, we would like to thank

Ann Lavedan of NTIS for her patient and careful attention to the preparation of the

translated manuscript.

- vii-

PREFACE

In this report, we have tried to examine topics related to response-control

structures, base isolation structures and to analyze the trends of future technological

developments.

Current studies of response-control structures and base isolation structures are being pursued from various viewpoints. A number of such buildings and structures

have been built in various coimtries. In Japan, too, several new buildings have

incorporated the base isolation concept. If we include the plans that have already

been approved by the Minister of Construction, this number exceeds ten. In Japan,

base isolation structures use laminated rubber bearings and most of them were

developed by construction companies. In the future, in addition to base isolation

systems iising laminated rubber, we expect to see the use of active response-control

systems, such as the active mass response-control system. These techniques may be

used in various types of structures. It thus becomes necessary to conduct research on

technological development; the government must ascertain safety of these

structures and prepare guidelines for systematic technological development of these

structures.

Traditionally, earthquake-resistant structures have meant those constructed using

materials with adequate strength and ductility so as to withstand an earthquake.

Based on lessons from the damage due to earthquakes, seismic design methods for

earthquake-resistant structures rely on the mechanical dynamics, taking fundamental period of vibration of the structure, its restoring-force characteristics, energy absorption efficiency, etc. into account. Theoretically, the response-control or base

isolation concepts which form the main theme of this report are not entirely

different from conventional techniques. The only difference is that the fundamental

period of vibration of structure, the restoring-force characteristics or energy

absorption properties depend on structural elements in conventional systems but on

mechanical equipments in response-control or base isolation systems. Studies on

mechanical properties of such equipment, and surveys on the existence of special

problems inherent to response-control or base isolation are the main focus today.

Studies on earthquake ground motion are also important topics not only for

conventional earthquake-resistant structure, but for these new structural systems

This report is a first step toward the study of response-control structures and the

base isolation structures. The report itself examines the current statiis of responsecontrol structures and the base isolation structures, and more detailed studies wiU be

required in the next step.

The Ministry of Construction asked us to prepare a survey report on framing

guidelines for technological developments of base isolation buildings. To do so, an

expert Committee on "Advanced Technology for Building Structures" and a Special

- ix-
Task Group were set up at the Building Center of Japan to study new building

structure techniques. This report presents their findings. We express our gratitude

to Prof. Umemura who, as the adviser to the Expert Committee, guided the project,

and to all other members of the Expert Committee as well as the Special Task Group

who completed the study in so short a time that the report could be presented in this

form. Thanks are also due to the Building Center of Japan for the administrative

help they rendered.

Hiroyuki Aoyama

Chairman, Expert Committee on Advanced Technology

for Building Structures

-X-
Name of the building:

Observations started:

Yachiyodai Unitika-type

Base isolation Apartments

Yachiyo City, Chiba Prefecture

AprU 1983

Base isolation device

Viev^ of the Base isolation apartments

XI-
BUILDING OUTLINE

B

A

L ;L i . _,,

ll !i' 1'

Ij r! I| iL J'L J Roof

A

First

Bi

-n r--- -Tl

I II II >l ,

I II i I I ll I Q

" ' 1 I I L. ! ir

41.

, I '-F^

I I 1 r I

I

' N Ll ' — M.

floor

-F

£1

Basement 6.080 4.280

Ota c

B-B Section

A-A Section

1 o 1 ca !

,

,

$ o

II r-._ i: tii^l

1 m Folia ry 1

6.080 4.280

10.360 3 2

PLAN

-xii-
Name of the building Tohoku University

Experimental base isolation building

Sendai City > Miyagi Prefecture

Observations started: June 1986

Base isolation device

View of the experimental base isolation building.

Left-Building with conventional structure

Right-base isolation structure.

- xiii-
BUILDING OUTLINE

p

ii

Building

with

Conventional

Structure

UP

Building

with

Base Isolation Structure

Laminated rubber

o

T

J]

ot=— o

:

/Oil [" damperi

rn^o

Y 5,000 5,000 1,50C 5,000 5,000 l,5ol

1

10.000 3,250 10,000

•vUFL

73FL

72FL

5,000 5,000

PLAN

LRB

1_E

5lRFL_

7 2FL

.IFL 3f

Oil damper

1.500 5,000 5,000 1,500

10.000 3,250 10,000

SECTIONAL VIEW

- xiv-
Name of the building: Kajima Institute of Construction

Technology,

Acoustic and Environmental Vibration

Test Laboratory

Chofu City ,Tokyo

Observations started: June 1986

Various devices fitted at the foundation.

View of the acoustic and environmental vibration test building.

(Left - base isolation building; Right - building with conventional technique).

-XV-
BUILDING OUTLINE

LRB 165ton

LRB lOOton

Fail-safe Device

Damper

FOUNDATION PLAN

'Acuostic

j Reverberation

Room

Anecoic Room

SECTIONAL VIEW

- xvi-
Name of the building: Obayashi Technical Research Institute

61st Experimental Wing

(Hi-tech R&D Center)

Kiyose City,Tokyo

Observations started: August 1986

Base isolation device.

View of the 61st Experimental Wing.

- xvii-
BUILDING OUTLINE

LLoBp 3B

\

^ Damper

^LRB

3. too J

FOUNDATION PLAN i POSITION OF BASE

ISOLATION DEVICES

tmoU

3.600 _3600 X 6 =21600

O © © © © © 0

Terminal room

Equipment stand

i ""-s

i i J Piping stand

SECTIONAL VIEW (a-a)

- xviii-
Name of the building:

Observations started:

Okumura Gumi Tsukuba

Research Laboratory Administrative Wing

Tsukuba City, Ibaraki Prefecture

September 1986

View of the administrative wing

- xix-
4

Steel - loop type damper

BUILDING OUTLINE

[•¥1 ira r»*i

20400

6 5QQ I 7400 6S0Q

20 400

• ISOLATOR

89 DAMPER SECTIONAL VIEW POSITIONS OF BASE ISOLATION DEVICES

- XX-
Name of the building: Takenaka Komuten

Funabashi Taketomo Dormitory

Funabashi City,

Chiba Prefecture

Observations started: April 1987

Base isolation device

View^ of the Taketomo Dormitory

- xxi-
Piping and wiring

BUILDING OUTLINE

—tr- ~t—31 fies 1 ami hi

a

, ,4 J

© ® © ®

SECTIONAL VIEW

©

PLAN

L.

® ® © 37.200 © 0 ®

-Viscous damper O'LRB 200ton

680dia •:LRB ISOton

ARRANGEMENT OF DEVICES

- xxii-
Name of the building: Takenaka Technical Research Center

Model Test Structure

Koutou-ku

Tokyo

Observations started: 1984

- xxiii-
BUILDING OUTLINE

CROSS SECTION

- xxiv-
Name of the building:

Observations started:

Oiles Industries Technical Center (TC wing)

Fujisawa City, Kanagawa Prefecture

April 1987

Base isolation device

View of the TC wing

-XXV-
BUILDING OUTLINE

- xxvi-
LIST OF JOURNALS REFERRED TO IN THE REPORT

TRANSLITERATION TRANSLATION

Dai 7 kai Nippon jishin kogaku

symposium

Obayashi-gumi gijutsu ken-kyushoho

Demyoku doboku

Doboku gijutsu

ICXJ genshiryoku seminar

JEES

Kikai no kenkyu

Nikkei mechanical

Nippon genshiryoku joho center

Nippon gomu kyokai-shi

Nippon kenchiku gakkai, Chugoku

Kyushu-shibu

Nippon kikai gakkai koen ronbunshu

Nippon kenchiku gakkai ronbun

hokoku-shu

Nippon kenchiku gakkai taikai

7th Japan Symposium of Earthquake

Engineering

Report of Obayashi Technical Laboratories

Electric Power Construction

Journal of Civil Construction Technology

ICU Atomic Power Seminar

Japan Earthquake Engineering Symposium

Studies in Mechanics

Nikkei Mechanical

Japan Atomic Power Information Center

Journal of the Japan Rubber Association

Journal of the Chugoku Kyushu Chapter of

Architectural Institute of Japan

Papers Presented at the Japan Mechanical

Engineers' Association

Transactions of Architectural Institute of

Japan

Proceedings of Annual Conference of

Architectural Institute of Japan

- xxvii-
Nippon kenchiku gakkai, Tohokushibu

Nippon kenchiku gakkai, Tohokushibu kenkyu happyo-kai

Nippon zosen gakkai-shi

Rinji jigyo iin kai kenkyu hokoku

Seisan kenkyu

Taisei kensetsu gijutsu kenkyusho

hokoku

Tohoku daigaku kenchiku gakuho

Journal of the Tohoku Chapter of

Architectural Institute of Japan

Seminar of the Tohoku Chapter of

Architectural Institute of Japan

Journal of Japan Ship-building Association

Research Bulletin of Temporary Working

Group

Monthly Journal of Institute of Industrial

Science, Tokyo University

Bulletin of Taisei Constructions Research

and Development Laboratory

Bulletin of Architectural Department, • Tohoku University -'O

xxviii-
OUTLINE OF THIS REPORT

This report is a summary of the studies (Stage 1) by the Expert Committee set up at the Building Center of Japan (BCJ) to examine response-control structures and base

isolation structures during the fiscal year 1986 (FY). It consists of six chapters. The

main topics covered in each chapter and brief contents are:

Chapter 1. Aims and Objectives of the Survey - deals with the organizational details

and course of study and is in the nature of an introduction.

Chapter 2. Outline of response-control (or damper) structures. Section 2.1 explains

the technical terminology used in this report (including the terminology for

common reference). Here, we have defined response-control and base isolation

structures as follows:

Response-control (or damper) structure is a structure which controls or

restricts the response of buildings to external turbulence using a fixed device or mechanism that acts on the entire structure or its parts. The base isolation

structure mentioned below is one such example.

Base isolation structure (also called "Menshin" structure) is a structure which

controls or restricts the response of buildings to seismic waves by increasing

mainly the fundamental period of the structural system employing such

mecharusms as laminated rubber bearings sliding supports, a flexible first story or devices or mechanisms similar to these, v •

To examine all aspects of the response-control structure, we have proposed, in

Section 2.2, various methods of classification of structures from three different

viewpoints: 1) basic principles of dynamics; 2) methods of implementation; and 3)

position of devices. Representative models of each method of response-control

structure are given. Important considerations for these classifications and the types

of response-control structures in each class are also discussed. >

- xxix-
Classifications according to the above three viewpoints are as follows:

1. Classification according to the basic principles of dynamics:

Response-control structure:

methods based on control and adjustment of restoring-force characteristics;

methods based on control and adjustment of damping;

methods based on control and adjustment of mass;

methods based on control and adjustment of input force;

(or a combination of the above).

2. Classification according to the method of implementation:

Response-control structure:

passive control type;

active control type.

3. Classification according to position of devices:

Response-control structure:

external type (insulation type);

internal type (noninsulation type). : a

Section 2.3 reviews the history of seismic response-control building technology and

the cases of base isolation structure approved by Minister of Construction.

Trends in other fields, such as civil construction other than buildings, using re- sponse-control techniques in Japan as well as overseas, and the proposal for wind re- sponse-control structures are discussed.

Chapter 3. Possible applications of response-control structures - discusses the greater

flexibility in design that can be expected by using response-control techniques and

refers to several occupancies of buildings where the response-control technique can be used in the future. These applications will contribute to the solution of the following technological problems: -i

1. Ensuring safety of structures under emergency conditions;

2. Reducing cross section of structural members;

-XXX-
3. Prevention of vibration, sliding or tumbling of furnitures;

4. Prevention of damage to or peeling off of nonstructural elements;

5. Prevention of uncomfortable vibratior\s; and

6. Ensuring performance of machines or equipments installed in buildings, etc.

Chapter 4. Various aspects of response-control structures - discusses topics to be dealt

with so that the response-control structure can be developed properly in the future.

In Section 4.1, some comments are offered from a technical point of view about: 1)

external turbulence; 2) methods of dynamic analysis; 3) design methods; 4) re- sponse-control devices; 5) construction; and 6) maintenance management.

In Section 4.2 we have discussed social and governmental issues such as: 1) guidelines for technological development; 2) simplification of the permission process; 3)

optioris for designers and developers; 4) encouragement of high technology; 5) ex- change, accumulation and active use of technical information; and 6) method of

evaluation of the effect of response control.

Chapter 5. Evaluation of the effectiveness of the response-control structure. Section

5.1 discusses some aspects of evaluation, particularly for base isolation structures of

Meiishin type.

Five points are raised for evaluation: 1) safety; 2) living comforts; 3) performance;

4) economy; and 5) flexibility of structural design.

Section 5.2 discusses in greater detail evaluation of the safety of Menshin structures

using base isolation. Here we have offered some comments on: 1) the design

criteria; 2) design seismic ground motions; 3) method of dynamic analysis; 4)

method of bearing design; 5) performance of base isolation equipment; 6)

construction; and 7) maintenance management.

Chapter 6. Summary - reviews the salient points noted during this study and

considered useful for the effective development of response-control structures in the

future (1987 onwards):

1) preparation of guidelines for the evaluation and approval of base isolation

structure;

2) preparation of guidelines for the performance of base isolation equipment;

3) exchange, collection and dissemination of technical information about

response-control structures; and

4) study of methods of evaluation of performance of response-control

structures.

-xxxi-
The following three appendices are provided:

Appendix 1 . Variability of the performance of response-control structures;

Appendix 2. Examples of response control against wind;

Appendix 3. Bibliography.

- xxxii-
CHAPTER 1

AIMS AND OBJECTIVES OF SURVEY

Traditionally, while designing structures to withstand vibrations due to

earthquakes or wind, the aim was to make the structure vibration resistant by

improving its strength, ductility and stiffness.

Devices to prevent the propagation of vibrations to the structures or the

installation of devices that will absorb the energy of vibration have long been

proposed. Only recently, however, has such research progressed so that the findings can be used in actual construction. Structures using this technique are variously

referred to as "Seishin structure," "Menshin structure," "Boushin structure" or "Genshin structure" in Japan. The aim of these techniques is to improve safety and

damping of sway; the technological details involved touch several disciplines.

Such a response-control or base isolation structure generally tries to regulate the re- sponse of a building to vibrations by using some kind of device. Naturally, to ensure

safety and proper design, knowledge of structural dynamics alone is not enough. It is equally necessary to pay attention to the safety and endurance of the devices used,

including their upkeep and maintenance. This method uses some qualitatively different approaches than those used in the conventional structural design such as "earthquake-resistant design."

The enforcement of the current (conventional) regulations for buildings is unrea- sonable in those modern buildings incorporating response-control structures and

base isolation structures. We do need, however, to evolve new design and safety

standards based on the properties of response-control structures or base isolation

structures. For this purpose, further study is required of various aspects including

factors related to structural design such as design earthquake ground motions and

design wind effects and the evaluation of required performance of such structures

for different occupancies.

Of course, it is also necessary to develop devices (gadgets) to ascertain the

performance and reliability of response-control structure or base isolation structure.

Today, there is no consensus in the building construction industry on the policy of

using response-control structures or base isolation structures. Various research laboratories are probing all the aspects mentioned above and are independently con- ducting research or experiments. There is seemingly some confusion about use of

the terms "response-control structure" and "base isolation structure."

-1-
It is therefore essential to evolve some method of evaluation of the feasibility and

safety of these structures. The response-control structure or base isolation structure

is a technology with bright future. Since its development is likely to be continuous,

for the systematic progress of this work, it is necessary to compile information on

various approaches to and topics of technological development in the field.

Aware of these various needs, the Ministry of Construction decided to conduct a survey of these issues in cooperation with the Building Center of Japan, as a sequel

to their on-going study; the study proposal was sent to the Building Center of Japan.

At the Building Center of Japan, an Expert Committee on Advanced Technology

for Building Structures (Adviser: Hajime Umemura, Professor Emeritus, Tokyo

University; and Chairman, Hiroyuki Aoyama) was formed. At the first stage of the

study, it was decided to collect information on the technological and legal aspects of

the response-control structure and analyze the trends of future technological development.

Under the Expert Committee for Advanced Technology for Building Structures a

Special Task Group (STG) was formed to conduct this study; this STG actually con- ducted the work under the guidance of the Expert Committee. The findings were

submitted to the Ministry of Construction in the form of a report. The present report

is an edited version of the same report for the general public. The names of the

members of the Expert Committee and Special Task Group are listed elsewhere in

this chapter.

1) Approach

1) The study will be carried out in two stages. Stage 1 will be conducted in FY

1986 and Stage 2 in FY 1987 and after.

2) In Stage 1, in FY 1986, the essential topics related to response-control

structures and base isolation structures will be compiled and the future

technological developments will be assessed. These will be pursued in the

following order:

a. compilation of the technical terminology to be used;

b. classification and compilation of the present proposals;

c. an overview of the current status, problems faced and merits of each

method;

d. expected architectural applications;

e. identification of problems and topics related to response-control structure

and base isolation structure;

f. identification of topics for future studies; and

g. summary of findings and introduction to Stage 2.

3) During Stage 2 in FY 1987 and after, the parameters for evaluation of safety in

the base isolation system are to be compiled; based on the findings in Stage 1,

-2-
some further study of topics which the Expert Committee considers

important will be carried out.

2) Organization

1) The organization of Stage 1 will be as follows:

1. A special task group (STG) to be formed within the Expert Committee;

2. The Expert Committee should assign the task to STG and give it directions

under which to operate and conduct the study;

3. Based on the guidelines of Expert Committee, the STG should prepare a

classification and compilation of various proposals and list the problems

in each method to be reported to the Expert Committee;

4. Structure of the Expert Committee and STG will be as described below.

2) Organization for Stage 2 will be decided after considering the findings in Stage

1; the strength of members may be increased if necessary.

-3-
Expert Committee on Advanced Technology

for Building Structures

Consultant / Adviser

Hajime Umemura

Chairman

Hirouki Aoyama

Members

Masanori Izumi

Yutaka Inoue

Kiyoshi Kaneta

Masahiro Kawano

Koichi Takanashi

Hideyuki Tada

Kiyoshi Nakano

Chairman of the Board of Directors,

Shibaura Institute of Technology, Professor

Emeritus, Tokyo University

Professor, Department of Architecture,

Faculty of Engineering, Tokyo University

Professor, Department of Architecture,

Faculty of Engineering, Tohoku University

Professor, Department of Architecture,

Faculty of Engineering, Osaka University

Professor, Department of Architecture,

Faculty of Engineering, Kyoto University

Assistant Professor, Department of

Architecture, Faculty of Engineering, Kyoto

University

Professor, Department of Building and Civil

Engineering, Institute of Industrial Science,

Tokyo University

Professor, Department of Architecture,

Faculty of Engineering, Fukuoka University

Professor, Department of Architecture,

Faculty of Engineering, Tokyo Denki

University
Hideo Moriya

Makoto Watabe

Makoto Tateishi

Tatsuo Murota

Takeshi Goto

Toshihiko Kimura

Shoichi Yamaguchi , i

Toshikazu Takeda

Kozo Touyama t

Isamu Harada

Shiro Yajima

Shigetaka Abe

Professor, Department of Architecture,

Faculty of Engineering, Chiba University

Professor, Department of Architecture,

Faculty of Engineering, Tokyo Metropolitan

University

Chief, Building Guidance Division, Housing

Bureau, Ministry of Construction

Director, Structural Engineering

Department, Building Research Institute,

Ministry of Construction

Director, Building Center of Japan

President, Kimura Structural Engineers

President, Tokyo Kenchiku Structural

Engineers

Deputy Director, Technical Research

Institute, Obayashi Corporation

Head, Second Research Division, Kajima

Institute of Construction Technology,

Kajima Corporation

Assistant Director, Design Division,

Shimizu Corporation

Manager, Technology Development

Department, Taisei Corporation

Deputy Manager, Structural Engineering

Section, Building Design Department,

Tokyo Main Office, Takenaka Corporation
Special Task Group

Adviser

Masanori Izumi

Chairman

Tatsuo Murota

Members

Yoshitsugu Aoki

Jun Kanda

Tetsuo Kubo

Akira Wada

Yoshikazu Kitagawa

Yuji Ohashi

Takayuki Teramoto

Hidetoshi Nakagami

Hiroshi Okada

Professor, Department of Architecture,

Faculty of Engineering, Tohoku University

Director, Structural Engineering

Department, Building Research Institute,

Ministry of Construction

Assistant Professor, Department of

Architecture, Faculty of Engineering, Tokyo

Institute of Technology

Assistant Professor, Department of

Architecture, Faculty of Engineering, Tokyo

University

Assistant Professor, Department of

Architecture, Faculty of Engineering,

Nagoya Institute of Technology

Assistant Professor, Department of

Architecture, Faculty of Engineering, Tokyo

Institute of Technology

Head, Civil Engineering Division, USEE,

Building Research Institute, Ministry of

Construction

Scientist, Dynamics Division, Structural

Engineering Department, Building Research

Institute, Ministry of Construction

Chief Structural Engineer, Nikken Sekkei

Ltd.

President, Jyukankyo Research Institute, Inc.

Manager, Structural Engineering

Department, Technical Research Institute,

Obayashi Corporation

-6-
Satoshi Bessho Chief Research Engineer, Second Research

Division, Kajima Institute of Construction

Technology, Kajima Corporation

Masaru Sukagawa Manager, Technical Development

Department, Technology Division, Shimizu

Corporation

Soichi Kav^amura Manager, Earthquake Engineering Section,

Technology Research Center, Taisei

Corporation

Yutaka Hayamizu Chief Research Engineer, Structural

Engineering Group, Technical Research

Laboratory, Takenaka Corporation

Associate Members

Yasuyuki Fujiwara Assistant Manager, Building Guidance

Division, Housing Bureau, Ministry of

Construction

Koichi Koshiumi Section Manager, Building Guidance

Division, Housing Bureau, Ministry of

Construction

Hitoshi Shiobara Scientist, Structural Engineering

Department, Building Research Institute,

Ministry of Construction

-7-
CHAPTER 2

RESPONSE-CONTROL STRUCTURES

2.1. Terminology

Various proposals and studies about response-control structures and base isolation

structures have long been made in Japan, as mentioned in Section 2.3. The definitions of terms vary according to the proposer or researcher and there is no uniformity in this respect. Our definition of terms and classification of structures have

been compiled based on this earlier literature.

2,1.1 Earlier terminology

In this section several definitions of terms used by earlier researchers are compiled.

Examples of such previously defined terms are as follows:

1. Damper type earthquake-resistant structure (Seishinsei Taishin Kozo): A

structure in which vibrations are damped, thereby imparting earthquakeresistant properties (Takabeya, Ref. 1).

2. Vibration control (Seishin): The amplitude of the vibrations developed in

the structure (subjected to vibration) due to the earthquake is controlled using

some mechanism (mainly damper or attenuating mechanism).

3. Seismic vibration prevention (Boshin), vibration isolation (Menshin):

Seismic waves are not allowed to pass to the structure due to some blocking

mechanism which cuts off seismic waves from the structure.

4. Earthquake-resistant (Taishin): To make the structure withstand seismic

vibrations.

5. Earthquake-resistant (Taishin): To fix the structure with respect to space

coordinates of seismic motion.

6. Vibration protection (Boshin), Menshin: To fix the structure with respect to absolute fixed space coordinates.

7. Seismic response control (Seishin): To impart such properties to the structure

that seismic vibrations are controlled.
(Definitions 2 to 7 are by Kobori and Minai. Ref. 2)

8. Menshin or base isolation method, Genshin method: Structural approach in

which the seismic vibration incident upon the structure are damped (Izumi,

Ref. 3).

9. Base isolation (Menshin) structure: A structure in which the response of the

main parts of the building to the seismic vibrations is damped by placing

some artificial auxiliary mechanism in the support (bearing) region. (Bulletin

of Denryoku Central Research Laboratory, Ref. 4)

References

1. Takabeya, Fukuhei. 1938. Damper-type vibration-resistant structures. Kenchiku

Zasshi, No. 636.

2. Kobori, Takuji and Ryoichiro Minai. 1960. Analysis of damper systems (Studies

on damper structures. Part 1). Kenchiku Gakkai Rombun Hokoku-shu, No 66.

3. Izumi, Masanori and Yoichi Kishimoto. 1975. Studies on damping methods in

buildings. Tohoku Daigaku Kenchiku Gakuho, No.16.

4. Matsuda, Yasuji; Sakae Aoyagi and Tetsu Shiomi. 1985. Survey of Menshin

structure. Bulletin of Denryoku Central Research Laboratory, October, 385010.

The foUov^ng technical terms are used for the response-control structure or base isolation structure. Although the terms are not clearly defined, we have provided

some explanatory comments for each of them for reference.

Base isolation: This is very close to the term "Menshin" used in Japan.

Generally, it indicates a structure using laminated-rubber support or sliding

support.

Soft or flexible first story: The horizontal stiffness of the lowest floor or the first floor above the ground is considerably lower than that of the upper floors thereby

increasing the period of oscillation of the entire system.

Response control: This term was used at the Ninth World Conference on

Earthquake Engineering and covers many terms such as "Seishin" or "Menshin"

generally used in Japan.

-9-
2.1.2. Terminology used in this report

Considering the definition of terms used in eariier studies and considering the use of

these terms in modern building industry, some terms are redefined below for the

purpose of the present study.

Response-control structure: This is a structure which controls or restricts the re- sponse of buildings to external forces through a specific device or mechanism

that acts on the entire structure or its parts.. The base isolation structure mentioned below is part of this.

Base isolation (or Menshin) structure : This is a structure which controls or

restricts the response of buildings to seismic waves by increasing mainly the

period of oscillation with the help of such mechanisms as laminated-rubber

bearings, sliding supports, a flexible first story, or devices and mechanisms

similar to these.

Base-isolation: Among various types of base isolation structures, rubberlaminated bearings or sliding supports are provided at the foundation of a

building.

Flexible first story: The horizontal stiffness of the lowest or the first story above

the ground is made considerably lower than that of the upper stories, thereby

increasing the fundamental period of oscillation of the entire system.

By the way, in mechanical engineering, we have terms such as vibration

elimination, vibration prevention, which are similar to the terms responsecontrol and base isolation . Although they are not directly used in this report, the

meaning of these terms is given here for the reference.

Vibration elimination: To isolate instruments or equipment from vibrations of a supporting structure or vibrations of a building.

Vibration prevention: To cut off the vibration of machinery not to pass to the

supporting structure or building.

2.2. Classification and Characteristics of Response -Control Structures

2.2.1. Classification

1) Previous classification

There have been many proposals and studies about response-control and base

isolation structures but little uniformity in the definition of terms used by

various authors or researchers.

This nonuniformity is also found in the classification of response-control

structures. Hence, the criteria of classification have varied. The main

-10-
classifications of the response-control structures in the past can be listed as

follows:

1 Residential

buildings — •Vibrationinsulation

structure —Fixed structure2, Base isolation

structure, Genshin

structure

3. Base isolation

structure

-Flexible

structure

JRigid

structure

(Sano & Muto, Ref. 1)

Insulation type

-Adjustable restoring-force type

-Energy-absorption type (damping type)

-Self-regulatory type

-Pendulum type

(Izumi, Ref. 2)

-Period lengthening type

-Energy-absorption type

-Decoupling type

-Screening type

-Special-structure type

(Kumar & Maini, Ref. 3)

-11-
Base isolation method -Adjustable-period (of oscillation) type

-Energy-absorption type

-Insulating type

-Special-structure type

-Self-regulatory type

-Screening type

Damper method

Passive

dampingActive

damping

(Denryoku Central

Research Laboratory, Ref. 4)

-Adjustable mass-and-stiffness

distribution type

'Adding external vibrating

system for damping

• Increase damping by

adding damper

Using hysteretic damping of

individual structural elements to reduce vibration

-To add an automatic system

which senses vibrations of the

building and then controls them

within the permissible limits

(Sakurai and Aizawa, Ref. 5)

-12-
To cut off the path of seismic

wave transmission

To isolate the frequency band

of the response-control system

from the frequency band of

seismic motion

To make the system aperiodic

and asynchronous by imparting

non-linear characteristics

To use energy-absorption mechanism

(Kobori and Minai, Ref. 6)

-13-
References

1. Sano, Toshiki and Kiyoshi Muto. 1935. Earthquake-resistant and wind-resistant

buildings. Tokiwashobo Publishers.

2. Izumi, Masanori. 1986. Base isolation structures of today. Kenchiku Gijutsu,

April.

3. Kumar, R.R. and T. Maini. 1979. A review of Seismic isolation for nuclear structures. EPRI NP-1220~SR-1979.

4. Matsuda, Yasuji; Sakae Aoyagi and Tetsu Shiomi. 1985. Survey of base isolation

structure. Bulletin of Denryoku Central Research Laboratory, October, 385010.

5. Sakurai, Joji and Satoru Aizawa. 1971. Studies on vibration damping in

buildings. (Part 1) Experiments on elastomer damper. Nippon Kenchiku

Gakkai Taikai, November.

6. Kobori, Takuji and Ryuichiro Minai. 1960. Analysis of response-control system.

(Studies on response-control structures. Part 1). Kenchiku Gakkai Ronbun

Hokoku-shu, No. 66.

2) Classification used in the present study

In this study, we decided to classify the structures in order to explore the current

status of response-control structures. To do so, we have tried to classify the

structures, as shown below, from three perspectives: 1) basic principles of

dynamics; 2) method of implementation (passive or active); and 3) according to position or placement. The details are mentioned in Section 2.2.2. Here, the

main classifications of response control structures from these three perspectives

are given.

1. Classification according to the basic principles of dynamics:

Response control structure- Based on control and adjustment of restoringforce characteristics.

-—- Based on control and adjustment of damping. —- Based on control and adjustment of mass.

Based on control and adjustment of input

vibration.

(or a combination of the above).

-14-
2. Classification according to the method of implementation:

Response control structure

-

Passive control type

-Active control type

3. Classification according to position or placement of response-control devices:

Response-control structure — -External type (insulation type).

-Internal type (noninsulation type).

3) Examples of Classifications

The following are schematic examples of response-control structures classified

according to the three criteria.

1) Classification according to the basic principles of dynamics:

Methods based on control and adjustment of restoring-force characteristics.

Lead damper

Steel plate Rubber

.,LRB

Flexible

1st story

Reduced relative displacement

1, between upper

I floors

j J J Concentration

I 1^°^ displacement

at the Ist story

Device for changing

stiffness

Computer

Sensor

Laminated Rubber Flexible First Story Variable Stiffness Mechanism

-15-
Methods based on control and adjustment of damping

Damper

( Shock

Viscous damper

absorber )

Methods based on control and adjustment of mass

Diaphragm

Mass Pump

Structural frame

Mass pump

Mass

j~^£Spring

Mass pump fitted

into the frame Dynamic Damper

Methods based on control and adjustment of input force

Cutting off

the seismic wave

Base isolation structure

Cutting off the surface wave

with a trench

-16-
2) Classification according to the method of implementation

Mass

Flexible First Story Dynamic Damper Variable Stiffness Mechanism

Active type

Mass

Computer

Sensor Ground

—I 1. motion

Active Mass Damper

3) Classification according to position of device

External (Insulation) type

/^Laminated rubber bearing

-17-
Internal (Non-insulation) type

Any given response-control structure can be variously classified from these three

perspectives. A so-called base-isolation type structure can be said to be of adjustable

stiffness and damping type or of passive control type or of external type structure.

2.2.2. Classification according to the basic principles of dynamics

1) Equation of motion

The resultant motion of a building when it is subjected to external forces such as earthquakes, winds or dynamic force due to the vibration of machinery employed

v^ithin the building, can be represented by the following equation:

m(x+ yo) -1- f(x J x) = p. (1)

Here, m, f(x,x) and p are, respectively, the mass of the building as a dynamical

' system, reaction force developed in the system and external force acting on it. x, x and X are respectively the quantitative response of displacement of the system

with respect to its origin, acceleration and speed, y© is the seismic acceleration

incident on the system. Even in multistoried structures, where the degree of

freedom of motion of the building is more than 2, a similar expression can be

used after replacing each term in this equation by a matrix or vector.

To simplify the process, we shall assume below that only an external force due to an earthquake acts on the building. [If only the seismic force is present, the term

of external force "p" becomes zero, if wind load is present or if the excitation source is present within the system, a similar treatment is possible even if the

external force is not zero.] By rearranging eq. (1) we get:

mx+ f (x, x) = - myo- (2)

In eq. (2), if we expand the term of reaction force f(x, x) in terms of the term

dependent on the velocity of the system (damping term) and term dependent

only on the shape of the system (reactive force term), we can write.

-18-
mx + cx + f(x) = - myo- (3)

The term of reactive force in eq. (3) is a function only of the displacement

response of the system and represents statically acting reactive force (static spring

reactive force). If we assume that the following linear (elastic) relationship exists

between the static spring reactive force (spring stiffness of the system is denoted

as k) and the response displacement of the system, then

f(x) = k-x. . - - , (4)

Eq. (3) can be rewritten asm X + Cx + k- X = -myo. ---kj,- -'-i:. (5)

If the time dependence of the system is nonlinear, assuming partial linearity, eq.

(3) may be written in terms of incremental terms, as follows:

mix + Cix + kj • Ax + fi(x) = - mi yo. (6)

Suffix i in eq. (6) represents the condition of motion at the time ff.

The motion of a building under the action of a dynamic external force can be

determined using eqs. (1) to (6). Accordingly, to control the quantitative response

of the system to external force (displacement, velocity, acceleration and spring

reactive force developed in the system), it is necessary to control the shape

parameters of the system, namely, k, c and m in the above equation of motion

and the magnitude of external force incident on the system (y) in the above

expression). We shall discuss below the control methods based on the equation

of motion.

2) Target response to be reduced

The object of the response-control structure is to reduce the response of the

building. This reduction is desired in any of the following four responses (or

their combination):

1. System displacement (relative displacement, or incremental deformation), (x)

2. Reactive force developed in the system (static spring reactive force), if)

3. System acceleration (absolute acceleration), (x + yo)

4. System velocity (absolute velocity), (x+yo)

The relationship among these four response parameters can be summarized after

considering eqs. (1) to (6) as follows:

-19-
1. If we minimize the deformation (x) developed in the system, the reactive

force developed in the system (f) will also be small [eq. (4)]. In the case of an

elastoplastic system, this relationship may not be exact but may hold good for

the system where hysteretic damping force can be ignored. On the other

hand, it is necessary to reduce the reactive force if =k- x, if displacement (x) is to be reduced.

2. Reduction in absolute acceleration (x+yo) reduction in the reactive force

{f=kx are interdependent. The amplitude of force developed as a reaction is proportional to absolute acceleration [eq. (2)].

3. By reducing the displacement response of system (x), it is possible to reduce

the velocity response (x). As a result, the amplitude of absolute velocity (x +

yo) also decreases.

3) The basic principles of response-control structure *

A. A structure in which the restoring-force characteristics are controlled:

i) Control of linear elastic stiffness

This approach tries to reduce the stiffness of the system so that the

fundamental period of oscillation of the system is longer than the

predominant period of vibration of the external seismic force, thereby

, reducing response acceleration. Figure 1 is a typical example of a response

spectrum of an elastic system with one degree of freedom. Here, we can see

that the response acceleration decreases in the range of fundamental period of

the system larger than that of resonance [here, the absolute acceleration of (x + yo) is assumed. Hereafter, unless specifically mentioned, absolute ac- celeration is assumed.]

-20-
ELASTIC RESPONSE SPECTRUM

IMPERIAL VALLEY EARTHQUAKE OF MAY 18, 1940 ( M = 7.1 ) EL CENTRO, NS COMPONENT

Damping =0, 2, 5, 10 and 20% of critical

a. 02 0.06 0.1. 0.2 0.6 1.0 2.0 6.0 10.0

PERIOD - SECONDS

Fig 1. Example of the elastic response spectrum of a system

with one degree of freedom.

Let us consider an extreme case in which the stiffness k is assumed to be zero. If we

ignore the term due to viscous damping, then from the relationship of eqs. (3) and

(4), the response (x) and input (y) are in phase opposition and the absolute

acceleration response, which is the sum of these two, becomes zero. Behavior of

such a system is similar to that of the seismograph. If the stiffness of the system is assumed finite, some reactive force f =k • x is generated in the system under such

conditions. We must note that as we reduce stiffness k, the response deformation

occurring in the system(x) increases according to the relationship of expression (4).

[In an extreme case, as mentioned above, it becomes a ground displacement.]

-21 -
ii) Control of nonlinear elastic stiffness:

Here, an attempt is made to reduce the response of the system by imparting

some nonlinear properties to stiffness. In one case, some nonlinear

properties are imparted to the restoring-force characteristics of the system

using steel wire ropes as bracings, thereby avoiding resonance. In such a case, stiffness varies with the increase in displacement, thereby reducing the

quantum of response.

In another case, the response can be reduced by modifying the oscillation

properties of the system so artificially that an oscillating condition does not

develop. This is achieved by actively controlling the stiffness. However,

modification in the oscillation properties of the system does not necessarily

reduce vibrations due to an external force; the response may actually increase

as a result of modification in oscillation properties. Thus, it is important to control the modification in stiffness properties so that response does not

increase.

iii) Control of elastoplastic restoring-force characteristics:

In this approach, the relationship between the displacement {x) and static

spring reaction force f=k-xmeq. (4) , namely, the hysteresis of the system, is controlled.

When a load or external force is applied to the building, the yield condition

may be developed in the structural members and their behavior may become

plastic. As a result of the plastic behavior they absorb part of the vibration

energies, which is proportional to the area enclosed by the hysteresis loop. It thereby attenuates the amplitude of vibration. The following conclusion can be drawn for the load-bearing capacity of the system to be controlled: The

smaller the load-bearing capacity of the system, the larger is its elastoplastic

response. To reduce the response, it is necessary to maintain large load

bearing capacity in the area in which significant plastic deformations occur and to design structural frames so as to have significantly large area of the

hysteresis loops.

B. A structure in which the damping of the system is controlled:

Here, the response is reduced by increasing the damping effect. The effect of

response reduction by increasing damping can be seen in the response spectrum

of Fig. 1. It is clear that the response value decreases as damping increases. The

effect of increasing the damping can be estimated from eq. (3). Thus, increasing

the value of damping force term (cx) in this equation means reducing the static

spring reactive force if = k- x). Damping dissipates some amount of energy by

transforming it into heat using the damping mechanism. This results in

reduction of the vibration energy accumulated in the system in the form of

structural deformation or response vibrations.

-22-
When a building is considered as an elastic system, the vibration energy

developed in the system due to the external force must be dissipated using the

damping mechanism, otherwise vibrations continue for a long time without any

damping in their amplitude.

Methods to control damping include base-isolation systems using a combination

of various types of dampers and laminated rubber bearings or other systems

using a combination of bearing wall or braced wall and dampers.

C) A structure in which the mass of the system is controlled:

In this approach, vibration properties of the system are modified and the

vibration response is reduced by controlling the total mass (m) or its partial

distribution in the system.

The earlier technique called "inertia mass pump" corresponds to this. Here, the

value of mass (m) in motion is varied according to the response of the system

and in the vibrating system is not allowed to reach steady state. If a system is designed properly, it will not reach steady state of vibrations, hence resonance which might cause a large response does not occur.

In this method, it is essential to control the system conditions with high-fidelity

to the change of external conditions. If not, effectiveness of the system must be

examined on reduction of the transient response.

D) A structure in which the input force is controlled:

This approach reduces the vibration response by controlling the input such as acceleration (yo). Controlling the source of vibrations is one method to control

input acceleration (i/o). When the source of vibrations is a natural one such as an

earthquake, it is impossible to control its occurrence. We can attempt to isolate

the earth's surface very close to the building from the rest by such methods as making a trench or moat. When the vibration source has lower energy, such as

that due to automobile traffic, it may be possible to control the source itself. When the external force is that of wind, it is generally impossible to control its occurrence and the magnitude of wind pressure incident on the building. Its effects can be modified by giving the appropriate shape to buildings. The

technique of affixing spoilers to cylindrical chimneys, and thereby avoiding

resonance, is one example of this type of control.

While considering the control of systems existing within a building, the input to the system will be (x+ i/o) as is clear from expression (2).

-23-
2.2.3. Classification according to the method of implementation

A response-control structure, or a structure which can restrict and control the re- sponse of a building to external turbulence, may be classified in two ways: 1) that in

which it is necessary to apply some form of external energy for this control; and 2)

that in which such energy is not required. We term this classification as classification according to the method of implementation. The former is called the active

method while the latter is called the passive method.

In terms of this classification, the following methods to reduce the effect of external

force can be classified as active methods. The seismic vibrations or the vibrations in a building are sensed by an accelerometer and then the stiffness of the braces is controlled accordingly by a computer such that vibrations of the building are reduced

(variable stiffness mechanism) or some mass is placed on the top floor of the building and the vibrations are reduced through an actuator (active mass damper).

Methods such as base-isolation using laminated rubber bearings or a flexible first story are classified as passive methods.

According to the law of increase of entropy, if there is no energy incident from the

external source in nature, the system is transformed into a chaotic one with the

passage of time and it does not return to its original state (irreversible entropy). On

the other hand, if external energy is applied on to the system, it turns into a still more ordered state or the state of still less entropy.

Consider the high-rise, multistory steel-structure buildings. Large amount of energy

is applied to iron ore, the most stable iron form, by melting it in a furnace or rotary

converter and ultimately iron sections of high strength are manufactured by reduction. These materials are used as specified by computer-aided structural design. The

steel structure is built up to a height of 200 meters using large cranes. The energy

used for the construction of one building consists not only of heat and electricity, if we consider human knowledge, past experience and accumulation of information,

the total energy consumed will be substantial. A building made with such energy

inputs is subjected to extremely low entropy conditions or, in other words, to high

potential energy conditions, that is, in an unstable condition. Unless proper rust- proofing treatment is carried out, the steel bars may return to their original iron

oxide form. Thus, under the action of loads present in the structure, columns and

beams, under the above circumstances, may weaken and finally the building may

collapse. This is the meaning of unstable condition.

It may appear that construction of a building amounts to defying the universal law

of increase in entropy. A life of 60 years means maintaining the original strength even after it is subjected to various kinds of external forces during that time.

Generally, maintaining things in the state of lowest entropy is a refined way and also

often suitable for their use or exploitation. Thus a computer-controlled traffic signal

system in a metropolis is not as simple as the elevators in a tall multistoried building. Roads are provided for vehicular traffic and elevators for human traffic. In addition, there is a software control to regulate large volumes of traffic. It is possible to

-24-
create a state of low entropy by controlling this kind of information. However, if the

computer fails, we know the chaos that wiU ensue in such a high-volume traffic.

Previously, the hardware approach, both static and dynamic, was practiced to help

buildings withstand static forces, earthquakes and other shocks and to prevent undesired vibrations due to wind. Even this approach may be realized using computer

control or electronic techniques similar to the example of the traffic signal. Thus, the

vibrations similar to an incident earthquake may be induced in the building much

before the actual seismic wave reaches the building. The actuator is operated under

computer control and the building structure is maintained under low entropy condition.

Previously, buildings were protected from external turbulence by a combination of

hardware approaches and were made safe enough to last 60 years. The future approach may be to keep the building structure under a state of low entropy by software

control. This technique has been proposed in quite a few cases and may be implemented in some buildings in the near future.

In areas other than building constructions, particularly where cost is no consideration, such as in defense or space applications, this approach is possible. The Control

Configuration Vehicle (CCV) is one such example. This is a kind of aircraft which is purposely designed to be unstable and then stability is imparted by computer control.

There are many hitherto impossible features in this machine. The aircraft can change its course while flying straight in the air without changing the direction of its nose. - >

Another example is that of the large parabolic antenna fitted to a space satellite.

While the inclination of antenna changes, no vibrations are caused to its skeleton

and the desired rotation is achieved in one step where it stops automatically. The

structure of the parabolic antenna skeleton is specially made such that the stiffness can be varied according to the current flowing through it. The stiffness is controlled

by a computer.

These techniques are very expensive today. There is another problem in addition to cost while applying such techniques to buildings. In the earthquake-resistant struc- ture or base isolation (Menshin) structure incorporated in the building, the hardware

may be expected to behave as per their designed performance perhaps once in 100

years in response to an earthquake. This poses no problem. However, when the

control is achieved by software or other active methods such as actuators requiring

some energy input for operation, the system may not operate faultlessly during such

a rare phenomenon as an earthquake. As mentioned in other applications above, if the system is designed such that its computer operates normally all the time and it vibrates the building continuously with a given amplitude without any ill effect on

human beings, the computer can be expected to impart vibrations of a specified amplitude to the building when the external force (seismic waves or vdnds) is incident,

whether small or large. It is difficult to ensure the reliable operation of any device if

it is supposed to operate only once in 100 years, suddenly with the occurrence of

earthquake.

-25-
Devices such as laminated rubber, steel-rod damper, lead damper, oil damper, sliding

friction and others used to make response-control structures of base isolation

structures, act dynamically as hardware components. Methods based on devices such

as the computer, electronic techniques, actuators and others can be called software

dependent mechanisms. As mentioned earlier, some electrical energy is usually

necessary for operation of the latter and they are called "active" since they actively

respond to the structure. The former devices do not require any external energy and

act only at the time of an earthquake. For this reason they are called "passive." By

the way, some persons say that designing an earthquake-resistant structure to withstand an earthquake is an active human activity and so the structure can be

called an active system.

2..2A. Ciassification according to the Position of Dampers

There are two types of controlling response: the response-control or base isolation

(Menshin) structure using certain types of devices outside the building, or the "base

isolation method," and the other method based on installing certain mechanisms

inside the building. Here the former is called the "external" type and the latter the

"internal" type. It may be difficult to determine whether the place in which the device is installed is within or without the building. The boundary will vary according

to the structure. Here, we have used the term "inside" for that area which is used for

residential purposes. If most of the energy at the time of an earthquake can be absorbed by the device installed outside, then the response of the upper structure can be controlled in the elastic region and the deflection of the upper structure occurring

at the time of an earthquake can be minimized. As a result, the design of secondary

structural members is easier than that of the main building. Conversely, devices

installed "inside" the building, design of the upper structure or the secondary struc- tural members, becomes only slightly easier compared to the conventional building

design but there is no material difference since, in this method, some deformation of

the building itself is allowed.

2.3 . Examples of Proposals for Response-control Structures

and Actual Constructions

2.3.1. Examples of historical importance in the Japanese construction industry

The effect of response-control can be confirmed using the theory of vibrations or the

response analysis. Such scientific analysis, in particular numerical analysis, has become possible only in the last 20 years. However, even without such sophisticated

analysis, people have considered separating the building from the earth's crust to re- duce the shock of an earthquake. Proposals aiming at reducing the intensity of

earthquake effect or controlling the vibrations of a building in response to an

earthquake were made long before such sophisticated techniques as response analysis

were developed. Most of these proposals were only as suggestions or ideas and rarely

were they tested in practice. These ideas have often emanated from people with

varying expertise in the subject, people who were novices in construction or

specialists who offered suggestions based on theoretical knowledge and practical

experience. We discuss below the ideas about those structures or cases of buildings

-26-
and the theory of antiseismic structure published in papers mainly in Kenchiku

Zasshi (Journal of the Architectural Institute of Japan).

1) Base isolation structures in the Meiji period

The oldest published report about the base isolation structure is probably a paper

by Mr. Kozo Kawai based on a lecture in May 1891 and titled, "Structures free

from the maximum vibrations during earthquake - synopsis of the lecture." This

article appep.red in the December 1891 issue of Kenchiku Zasshi of the

Architectural Institute of Japan (previously the Japan Building Society) (Fig. a).

Fig. a. Kozo Kawai: Structures free from maximum seismic vibrations.

This report discusses a building equipped with precision instruments such as chemical balances and various meters which are sensitive to vibrations. Among

the ideas mentioned in this paper are these: 1) Several layers of logs are arranged

on the excavated surface of the earth's crust and held by fasteners. Cement

concrete is cast on these logs and then the building is constructed over them; 2)

Since it is known that high-rise buildings or flexible buildings sway easily, the

building is made low and the structure is triangular in shape; 3) To cut off the

seismic wave, a deep trench is dug around the building; 4) To protect

instruments such as balances from seismic vibrations they are mounted on

wheels so they can slide. Experts today may question Mr. Kawai's knowledge or the effectiveness of these measures. The first serious research on earthquake

engineering in Japan began with the Nobi earthquake of October 1 891 . As a step

toward modernization and to make the structure fire-resistive, the concept of the

brick structure was borrowed from western Europe. Since such explanations as Mr. Kawai's predated the beginning of the scientific studies mentioned above,

there were probably no alternative measures available. In this paper, the

objective is not to make the structure itself earthquake-proof but to protect

precision instruments from any damage. This confirms the value of the

response-control structure. The first base isolation structure proposed for a

patent was the one designed by J.A. Calantarients, an English doctor, who applied

for a U.S. patent in 1909 (Meiji 42) (Fig. b). In this structure, the building is

Sectional view Front view

-27-
isolated from the foundation using layers of talc so that the buildmg slides during

an earthquake. In this type of structure, considerable relative displacement is expected between the building and its foundation during an earthquake. For this

purpose, separate connecting fixtures (joints) were proposed for gas pipes and

drainage, allowing similar relative displacement.

Incidentally, in a letter written to an American friend, Calantarients mentions

that the base isolation structure proposed by him is not a copy of base isolation

(Menshin) structure proposed in Japan 25 years earlier, but is superior to that.

The paper by Mr. Kawai, mentioned above, was published 18 years before

Calantarients' design, which means that even before the publication of Mr.

Kawai's paper some Japanese proposals for a base isolation structure were known

abroad. The details of that base isolation structure are, however, not known

today.

Fig. b. Calantarients' base isolation structure (1909)

2) Theories about earthquake-resistant buildings and seismic coefficient

Three years before Calantarients' proposal, that is in 1906, a severe earthquake oc- curred in San Francisco. Calantarients' design was probably inspired by this

earthquake. The great San Francisco earthquake was the first in which the

modem American city on the Pacific Coast was aslo affected. All bricks and

wooden structures not protected by antiseismic treatment were greatly damaged

and more than half of San Francisco was engulfed in fire (about 28,000 houses in

an area of 12 square kilometers). Contrarily, reinforced concrete houses that were

under construction showed greater fire resistance or earthquake resistance. Prof.

Toshiki Sano of Tokyo Imperial University was a member of the team

investigating the earthquake damage. He noticed the advantage of reinforced

concrete structures and thought this would be a useful innovation in Japan

where earthquakes are quite common; he started studies in that direction. Later,

Prof. Sano prepared a thesis entitled "Antiseismic building structures" (1914,

Taisho 3) based on his experience of the earthquake resistance of buildings. This

-28-
study is the foundation of the science of antiseismic building structure i throughout the world. In his book. Prof. Sano mentioned the concept of "seismic

coefficient," a term indicating the seismic force operating on buildings. The ' seismic coefficient is the ratio of acceleration due to earthquake acting on the

building to the gravitational acceleration. The seismic force acting on the

building can be calculated by multiplying the weight of the building by the

seismic coefficient. He also suggested providing greater strength, and stiffness of

the building to help it withstand an earthquake.

From 1906 (Meiji 39), studies were undertaken at the Architectural Institute of

Japan, at the request of the then mayor of Tokyo, Mr. Yukio Ozaki, to draft

building regulations for Tokyo to be known as the Tokyo Metropolitan Building

Regulations. This study was completed in 1913 (Taisho 2) and the findings were

submitted to the Tokyo Municipal Government. This was the beginning of the

Building Regulations Act which is the first form of modem building regulations

enforced in Japan. Although the Tokyo Metropolitan Building Regulations were

framed after considering many building examples in cities of Europe and the

USA, the section on the strength of these buildings was prepared by Prof. Sano.

Based on these proposed regulations, the Metropolitan Building Regulation Act

was passed in 1919 (Taisho 8) and, consequently, the Metropolitan Building

Construction Rules were passed in 1920 (Taisho 9). Here, for the first time,

specifications for the structural design of buildings were enumerated. The load

and external forces taken into consideration while laying these specifications

were the dead load and the live load of the floors only. The allowable stress of

the material was so defined that safety factor is three.

The great Kwanto earthquake of 1923 (Taisho 12) caused heavy damage to building structures around Tokyo. This calamity provided a great impetus to the

studies of antiseismic structures and the Building Regulations Act was greatly

modified as a result. The specifications for structural design in the Metropolitan

Building Construction Rules were modified as a result. The specifications for

structural design in the Metropolitan Building Construction Rules were

modified in 1924 (Taisho 13), the year after the Kwanto earthquake, the seismic

force in which was determined according to Prof. Sano's concepts of seismic

coefficient. The guidelines indicated that the safety factor should be 3 while the

horizontal seismic coefficient should be assumed to be more than 0.1. Similarly,

obligatory positions of bracings and bearing walls for buildings of steel

construction, and the length of lap joints of steel reinforcements or the

reinforcement ratio in columns for reinforced concrete construction were defined

for the first time.

Around the same time, maybe as a result of the heavy damage caused by the

Kwano earthquake, proposals for base isolation structures were offered in Japan

and patents were even applied for. In 1924 (Taisho 13), the same year as the

Metropolitan Building Construction Rules were modified to include the

consideration of the seismic coefficient, Kenzabro Kito and Okiie Yamashita

proposed base isolation structures and patents were awarded to their proposals.

Kito's patent, "Earthquake-resistant gadgets for buildings," proposed using

concave dish-like parts between the foundation and the columns and ball-

-29-
bearings were inserted between the dishes thereby supporting the building (Fig.

c). Yamashita's patent, "Earthquake-resistant devices for building structures,"

proposed a structure wherein some sliding motion is allowed between the

foundation and the columns thereby reducing the impact of an earthquake on

the actual structure (Fig. d).

Column

® Bolt

n

Sill Sill

<2> L-^ Upper dish

- - J Spherical ball

^ -rr| Lower dish

Side view

6- Rolling mechnism

Side view

Top view of lower dish Top view of upper dish

Fig. c. Kenzabro Kito. Antiseismic devices for buildings (1924).

It also provided for a spring between the foundation and the column so that the

column returns to its original position (after the earthquake is over).

Column

Leaf spring

Cover plate

/^Jjpper sliding plate

Dish type column

support

Lower sliding plate

Leaf spring

Dish type

column support

Cross-sectional view Top view

Fig. d. Okiie Yamashita. Antiseismic devices for structures (1924).

-30-
3) Controversy between flexible and stiff structures

Although the great Kwanto earthquake provided a good impetus for studies on

earthquake-resistant buildings, it initiated controversies which continued for

several years about categorization of structures that can withstand earthquakes.

One such controversy was that of flexible and stiff structures, articles on which

were published in the issues of Kenchiku Zasshi, in the early years of Showa

period (around 1930), shortly after the Kwanto earthquake. This controversy

continued for several years. This debate was between Prof. Sano and Prof. Muto

of Tokyo Imperial University on the one hand, who held that to make a building

withstand an earthquake, it is necessary to reduce its period of oscillation and

make it stiff and on the other hand, Mr. Kenzabro Majima, Chief of the Naval

Architecture Department, who felt that the period of oscillations should be

increased and the structure made flexible so as to make it earthquake-resistant.

Since all these persons were directors of earthquake-resistant structural design in

Japan, and were advocating the opposite view, considerable interest was

generated in this subject.

It was almost 20 years before the effect of the base isolation structure in response

to earthquake could be examined analytically. It became possible to do so with

the development of strong-motion seismographs that can record the acceleration

generated by a severe earthquake and the development of computing techniques

for response analysis. The flexible-stiff controversy mentioned above began 30

years before such analysis could be carried out.

Even at that time, the basic equation for the condition of vibrations in a building

during an earthquake was known. Theoretical solution of this equation

considering some external force such as the harmonically oscillating force was

also obtained. However, at that time, the real nature of seismic motion was

probably not known. Most of the flexible-stiff controversy was due to differences

in the assumptions of the two sides regarding earthquake motion. Both the

flexible and stiff approaches try to avoid resonance of the building structure with

earthquake motion from the dynamic point of view, but there is considerable

difference of opinion about the period of earthquake motion the resonance at which period or frequency is to be avoided.

We cannot determine whether flexible structure or stiff structure is better unless

the properties of earthquake motion are clearly understood. Therefore, the

flexible-stiff controversy ended inconclusively.

Based on the present knowledge about earthquake motion, it appears that the

flexible structure advocated by Mr. Majima was a progressive approach. Flexible

structure is one of the principles of the base isolation structure and highrise

multistoried buildings in Japan can be built only with this flexible structure.

However, as a result of this controversy, most buildings in the world thereafter

incorporated the stiff structure. The Metropolitan Building Regulations were so modified that the height of buildings was restricted to 100 shaku (31 meters),

mainly to restrict urban population density. Later buildings were also based on

-31-
stiff structure to increase the resistance of a building. At this time seismographs

were not recorded nor were they analyzed; as such, the concept of stiff structure,

in which the structure is made stiff enough to be earthquake-resistant, was well

received.

During the flexible-stiff controversy, proposals for the base isolation structure

started appearing in Kenchiku Zasshi . In 1927 (Showa 2) Taro Nakamura

discussed earthquake resistance of buildings in terms of energetics and suggested

,that if some energy absorbing device is installed in the building, its earthquake

resistance will increase. He proposed a damper mechanism consisting of braces

with a pump damper In the same year, he discussed the case of a seven-story

reinforced concrete building where the joints at both ends of the basement

columns were of hinge structure and free horizontal slide was allowed between

the ground and the building. In addition, he proposed the installation of the

pump type damper (hydraulic damper) for energy absorption (Fig. e). Ryuichi

Oka made many proposals for the base isolation foundation for a few years since

1928 (Showa 3). In such a foundation, base isolation columns with a hemispherical surface at the bottom were erected on the foundation plate as shown in the figure (Fig. f). During an earthquake, some horizontal

displacement is allowed between the foundation and the upper structure as a

result of swaying of the base isolation column. Also, as a result of friction in the

spherical pin joints, the force of damping acting against the vibration also

increases so that the same structure can resist vibrations due to wind load. Mr.

Oka's idea, "Base isolation devices for buildings" was patented in 1932 (Showa 7).

This type of foundation is used in many buildings, some of which are mentioned

below:

Fig. e. Taro Nakamura. Device for seismic energy absorption (1927).

s

-32-
Fig. f. Ryuichi Oka. Base isolation foundation (1928)

*Insecticide sprayers stocking room, sewage section. Civil Engineering

Department of the Tokyo Metropolitan Council (located on Shibaura reclaimed

land, Shiba-ku, Tokyo, 1932, reinforced concrete structure, total floor area about

30 m2).

*Fudo Chokin Bank, Himeji Branch (1934, reinforced concrete structure, three

floors above ground, one basement floor, total floor area about 790 m^).

*Fudo Chokin Bank, Shimonoseki Branch (1934, reinforced concrete structure,

three floors above ground, one basement floor, total floor area about 640 m^).

The insecticide sprayers stocking room of the Tokyo Metropolitan Council was a structure of 8.2 x 3.5 m in plan size to test the effect of the base isolation

foundation. Next to it was constructed an identical building, without base

isolation. It was constructed for comparison with the structure with base

isolation foundation. Two buildings of the Fudo Chokin Bank are three-storied

reinforced concrete structures. The Himeji Branch building has base isolation

columns in the basement. Shimonoseki branch uses base isolation columns

between the ground floor and foundation slabs.

While the flexible-stiff controversy raged in Japan, it was proposed in the USA

that if the first floor of a building is made flexible, the force of an earthquake is not transmitted so strongly onto the remaining floors. Such a structure was

called the "Flexible first story" (or "Soft first story"). In Japan, too, a similar

proposal by Kenzabro Majima, as mentioned above, was patented ("Earthquake

resistant building structure") in 1934 (Showa 9). According to Majima's idea, in a

-33-
two-story structure, the ground and the first floors are structurally separate and

the first floor is supported by columns of low stiffness (Fig. g). Accordingly, twostory buildings were basically "Flexible first-story type." Even if the columns of

low stiffness collapse, a part of the first floor would still be supported by part of

the ground floor which is structurally independent.

Inside column!

of 1st floor

First floor walls which

operate as a fail-safe device

DB R DP

Elevation Elevation of first story

Inside column

Outside tubular column I i

Plan of first floor

Fig. g. Kemzabro Majima. Earthquake-resistant residential buildings (1932).

In 1938 (Showa 13), Oka constructed the basement of a building as a watertight

float and the structure was supported by the buoyancy equivalent to the mass of

excavated earth. He was granted a patent for this idea ("Foundation methods for

buildings"). In the same year, Fukuhei Takabeya of Hokkaido University, based

on his model shaking-table tests, proposed a structure in which a heavy mass

mounted on rollers is placed on the top floor of a building and vibrations in

structure are damped using the inertia of that mass (Fig. h).

\ n M,.,; n in

Fig. h. Fukuhei Takabeya. Response-control type earthquake-resistant structure

(1938).

This idea was patented in 1940 (Showa 15) as "Damper-type earthquake-resistant

structure." According to Takabeya, before this patent, Sezawa published a report

of experiments and analysis of a structure in which a kind of pendulum-like

device, which may be called a dynamic damper, is fitted to the structure. Ryuichi

Ika also published a report of model experiments using the roller structure of

Oakabeya and the other original proposals for base isolation structures.

-34-
4) Strong-motion earthquake records and the computer

Knowledge of earthquake ground motion is necessary while designing

earthquake-resistant structures. To gather such knowledge, it was necessary to develop a strong-motion seismograph and observation methods so that strong

seismic ground motion could be recorded. At that time, Suehiro, head of the

Earthquake Research Center of Tokyo University, explained the need to develop

a strong-motion seismograph and observation methods but his suggestions were

not well received in Japan. On the other hand, his views were understood in the

USA where a strong-motion seismograph was developed and observations began

in the early 1930's with California as its center. Acceleration records of strong

seismic motion were first available from the USA. [An example is the record at the El Centre Transformer Substation of the famous Imperial Valley earthquake

in 1940 (Showa 15). ] Based on such records of observations, M.A. Biot of the

California Institute of Technology discussed, for the first time, in 1932 (Showa 7)

the concept of response spectrum of seismic motion. In the USA, it was proposed

that the design seismic force (coefficient) be changed in response to the

fundamental period of oscillation of the building; this idea developed into a

structural design method with dynamic considerations. In Japan, acceleration

records of strong earthquakes were not available until the end of World War 11.

With the end of the War, Japan started its restoration. In 1950 (Showa 25), the

Metropolitan Building Regulations were suspended; it was planned to bring new

building regulations into force. At that time, structural design was based on such

specifications as the Extraordinary Japan Standard Specification 532 "Load on

Buildings," the Extraordinary Japan Standard Specification 533 "Guidelines for

Design of Buildings" (1944, Showa 19) or Japan Building Specification 3001

"Structural Calculations for Buildings" (1947-Showa 22). In addition, concepts of

"short-term" and "long-term" load, external force and allowable stresses were

introduced. As a result, the level of allowable stresses (short-term) was greatly

increased compared to the Metropolitan Building Regulations and, at the same

time, it was decided to assume the horizontal seismic coefficient of more than 0.2.

At the end of the War, the Japanese economy started growing at an astonishing

pace. Urban land became scarce and land prices soared. Available land had to be

used most efficiently. Therefore, highrise buildings were in demand. Around

1950 (Showa 25), foresighted researchers initiated studies of nonlinear vibrations

in building structures. However, it was only in 1959 (Showa 34) that Prof.

Kiyoshi Muto of Tokyo University and his colleagues prepared a project to study

the feasibility of high-rise buildings. The project was to construct a 24-story

building at the Tokyo Railroad Station of the Japan National Railways (JNR).

Analysis of the response of such high-rise buildings during an earthquake was

analyzed on the latest analog computer, based on the records of strong earthquake

motion in the USA. The results of this three-year study concluded that even

high-rise buildings can be made earthquake-resistant if the fundamental period

of oscillation is made longer.

-35-
The high-rise building of the Tokyo Raih-oad Station could not be constructed for

various reasons but it was clear that high-rise building construction in Japan, a highly earthquake-prone country, was possible. With this, the 31-meter

maximum limit on the height of buildings, set by the Metropolitan Building

Regulations mainly to control population density, was removed, and a floor

space index (FSI) was established (1963, Showa 38). Thereafter the high-rise

building boom started in Japan with the construction of Kasumigaseki building . Although restriction on the height of buildings had been removed, approval

from the Ministry of Construction had to be obtained for individual high-rise

buildings, since the safety of the design was certified on the basis of computeraided earthquake response analysis. Therein the designers have a tendency to assume smaller seismic force than that specified by regulations and as a result the

design differs from normal antiseismic building design.

Once the record of strong earthquake motion and the use of computers were

available, it was possible to analyze the effect of base isolation structures. The

first such analysis in the world was done by Kiyoo Matsushita of Tokyo

University and Masanori Izumi of Building Research Institute in the Ministry of

Construction. Together they presented a paper on the analysis of base isolation

structures wherein the foundation and the upper building are isolated using ballbearings.

! bl'dq

EARTH

0

iy = 0

«x or y

EARTH iyj

BLDO

-> X nt y

Fig. i. Vibration damper for seismic waves (1951).

Incidentally, prior to this, Sizuo Otsuki of Shimizu Constructions proposed using

rollers which operate in the directions normal to each other at the foundation

and the four sides are supported by springs (a device restricting the propagation of

seismic wave), and called it the vibration damper (Fig. i). Otsuki determined the

response of buildings fitted with this device assuming the seismic wave as a simple oscillating motion. Although the actual seismic motion is quite

complicated, by superimposing the waves (Fourier transform), he showed that

the method is effective if the fundamental frequency of oscillation of the system

is small. Subsequently, in 1954 (Showa 29), Takuji Kobori of Kyoto University,

during his study of nonlinear oscillating motion, noticed that using wires with

pre-tension and twisted wires as braces, the initial stiffness of a building is increased. If the response amplitude increases beyond a certain limit, the pre-

-36-
tension wires yield and shear off while the remaining twisted wires impart

nonlinear recovery characteristics to the building. The increase in wire

deformation of the building increases its stiffness as well. With this approach, resonance at the time of an earthquake is avoided. In 1957 (Showa 32), Takuji

Kobori suggested a prototype of the response-control structure using the example

of an atomic furnace where the reaction furnace is supported on both sides on

hinges and a spring is horizontally placed. In 1960 (Showa 35), Kobori defined

damping as experiencing seismic vibrations so that the seismic motion is restricted. He has published papers related to his study of the analysis of damper

system. In 1957 (Showa 32), Yasuhisa Sonobe of Tokyo University published a

report on analysis of the response-control structure using the friction damper and

the results of a shaking-table test for a building where a mass is suspended from

the top of the building. In 1964 (Showa 39), Chitoshi Katsuta of Tokyo Institute of

Technology published a report about the Menshin device (vibration-reducing

device) based on an electro-hydraulic type automatic control system. This was a sequel to his work on the development of a unique vibrating pad (Fig. j). In this

device, a seismograph is fitted in a structure supported by ball-bearings. The

relative displacement between the structure and the ground is detected and

corresponding signal is sent to the servo-system which in turn controls and

operates the actuator that in turn controls the behavior of the structure. Katsuta

made further improvements in this device and obtained patent in 1965 (Showa

40) for the "Menshin device." In this patent, a diagonal member is installed in

the foundation. An oil (hydraulic) cylinder with a servo valve, which operates

with a signal from an earthquake motion detector mechanism, is fitted to this

diagonal member. As a result, the upper structure is kept in a steady state even

during an earthquake, irrespective of the ground motion.

s21 -3 Ml 1 ^ X

E X

Fig. j. Chitoshi Katsuta. Base isolation method using auto-control (1964).

S - Structure; E - Earth's crust or underground structure in contact with earth's

crust; 1 - Support column; 2 - Seismograph; 3 - Horizontal support including

actuator; 4 - Servo-valve and actuator; X, Y, Y' - Displacement of earth's crust,

structure and center of gravity of pendulum, respectively.

-37-
structural frame

' Mass pump

Fig. k. Shigeya Kawamata. Mass pump (1973).

[Key: 1 - Mass pump 2 - Frame]

Other patents were also awarded during this period. For the damper structure,

we mention the proposal for "Earthquake-resistant foundation for structures" by

Shin'ichi Ishida, wherein the earthquake energy is absorbed by the foundation

pads installed between the upper level of the foundation and the columns by the

nearby soil. In the other proposal for "Earthquake-resistant, wind-resistant and

atom/hydrogen bomb-resistant buildings" by Shinya Mannen, a spherical

structure is allowed to float in a spherical dish-type foundation filled with water.

Both these methods are patented.

Developments continued and in 1973 (Showa 48), Shigeya Kawamata of Tokyo

University published his findings about damping the earthquake response using

a "mass pump" (Fig. k). In 1975 (Showa 50), Masanori Izumi of Tokhoku

University described a method called "Genshin" in which the effect of the

seismic force is reduced and the structure is made antiseismic. He published a review introducing the innovative proposals and studies on the "Genshin"

approach, analyzed the "Genshin" structure and offered some design examples.

5) Development of laminated rubber bearings and base isolation structures

In 1969 (Showa 44), a primary school building was constructed in Skopjie,

Yugoslavia, where they used rubber bearings designed by a Swiss national. These

rubber bearings were flexible horizontally and vertically. The rubber bearings are

effective in increasing the fundamental period of vibrations and thereby reducing

the seismic force; but this support also has to bear the load of the building. The

bearings in the Skopjie primary school posed some problems in supporting the

vertical load and construction works.

The idea of improving the bearing capacity of rubber bearings in the vertical

direction and maintaining its stiffness developed a few years later in France. This

development used "laminated rubber": thin rubber sheets and steel sheets were

-38-
arranged in many layers so that the composite material had flexibility

horizontally and stiffness vertically and could support a large mass. Using such

laminated rubber bearings, many base isolation buildings were constructed in the

late 1970's including the Lambesc Primary School in Marseilles, the Coebereg

Atomic Power Plant in South Africa and the Craus Atomic Power Plant in

France. Using a similar idea, buildings were constructed in the 1980's such as the

William Clayton Building in Wellington, New Zealand and the Foot Hill Law

and Justice Center Building in California, USA.

In Japan, with progress in the response analysis technique, it has become

apparent that the seismic force greatly decreases as the fundamental period of

oscillation of the building increases. In 1964 (Showa 39), the Architectural

Institute of Japan published a book entitled Design Guidelines for High-rise

Buildings. The Institute proposed the base shear coefficient for the design of

high-rise buildings which will reduce hyperbolically as the fundamental period

of building increases. The structural design specifications (as the Building

Regulations), however, were not modified accordingly. The seismic force for the

purpose of design was taken the same as before, and the horizontal seismic

coefficient of at least 0.2 had to be assumed in the design.

With developments in the response analysis techniques and with the occurrence

of Tokachi-oki Earthquake in 1968 (Showa 43), a survey under the Ministry of

Construction involving wide ranging technological development was conducted

for five years from 1972 (Showa 47). It was called "Development of new

earthquake-resistant design methods" and aimed at modifying the structural

design specification values (in the Building Construction Rules). In 1978 (Showa

53), an earthquake occurred near Miyagi prefecture and based on those

observations, structural design specifications values (in Building Standard Law)

were modified in 1981 (Showa 56). It was decided that the seismic force is to be

determined from the fundamental period of the building. With this, the

building designs could be approved even if the seismic force assumed is less than

the previously set limits, provided, of course, that the fundamental period of the

building is longer.

With modifications in the Building Standard Law and the construction of

earthquake-resistant buildings in Europe and America using laminated rubber

bearings, the studies on such buildings in Japan have been streamlined. The

residential base isolation building using laminated rubber bearings was

constructed by Hideyuki Tada of Fukuoka University in cooperation with

Shoichi Yamaguchi and Unitika Ltd. and others (1983, Showa 58). It was noted by

the Building Center of Japan as a special structure and was built with the

approval of the Ministry of Construction. Housing is one of the uses of the base

isolation structures. It was possible to apply this technique even to the atomic

power plant buildings and by doing so studies of the Menshin or base isolation

structure technology have rapidly expanded.

The response-control structure may involve other approaches in addition to the

laminated rubber bearings and many buildings are constructed using these approaches. These include Building No. 1 of Tokyo Science University built by

-39-
Matsushita mentioned above. Here, the stiffness of the basement floor is reduced

and the dampers are sandwiched between a double-column structure (1961,

Showa 56). A similar double-column structure is used for the Union House,

Auckland, New Zealand (1983, Showa 58). In another approach, a pendulum, as heavy as possible, is suspended from the top floor of the structure and by

allowing it to swing, vibrations to the building are reduced. Such dynamic

dampers are also used in the Sydney Tower, Australia (1975, Showa 50) and Chiba

Port Tower (1986, Showa 61). In yet another approach, a mass is placed on the top

of the building and is allowed to slide horizontally. This mass is controlled by an

actuator which operates with a signal from a detector, thereby reducing vibrations

to the structure. Examples of this approach (active mass damper) include City

Corp Building, New York (1977 Showa 52) and the John Hancock Center

Building, Boston. However, in these cases, the object is not to reduce the seismic

force but to reduce the vibrations of the tower due to strong winds (for recent

examples, readers are referred to the following section).

The history of response-control structures and building techniques used in the

above examples as well as details of regulations involved, etc., are listed in Table

2.1.

[This draft is based on a similar paper published in the May 1987 issue of

" Kenchiku Gijutsu (Architectural Techniques) by Yuji Ohashi and Shoichi

Yamaguchi.]

-40-
Table 2.1. Chronological survey of proposals for response-control structures

Earthquakes Academic activities Regulations Social events Proposals for response-control

and Menshin

structures

1 2 3 4 5 Meiji 10 (1877) Civil

Engineering Department

started in Engineering

College

Meiji 13 (1880) Japan

Seismology Association

established

Meiji 19 (1886) Building

Society established

Meiji 24 (1891)

Nobi earthquake

Meiji 25 (1892) Association

formed to estimate and

minimize damage due to earthquake

Meiji 24 (1891)

Kozo Kawai

published a paper on structures that can be free from

strong vibrations

during earthquakes (Fig. a)

Meiji 39 (1906)

San Francisco

earthquake

Taisho 3 (1914). Thesis on antiseismic building

structures by Toshiki Sano

Tokyo

Metropolitan

Building

Regulations

proposed

Meiji 42 (1090)

Calantarients

proposed the

Menshin structure

(Fig. b)

-41 -
Taisho 12 (1923)

Great Kwanto

earthquake

Taisho 11 (1922). Paper on

Earthquake-resistant

structures for buildings by

Tachu Maito

Rexible-stiff controversy

Showa 7 (1932) M.A. Boit

introduced the concept of

response spectrum

Showa 8 (1933) Method for calculating coefficient for distribution of horizontal

force in a reinforced concrete

structure (Kiyoshi Muto)

Taisho 8 (1919)

Urban Building

Regulations

declared (building

height below 31 m)

Taisho 9 (1920)

Building

Construction

Rules declared

(specifications for structural design)

Taisho 13 (1924)

Construction

Rules modified

(seismic

coefficient K = 0.1)

Taisho 12 (1923)

Damages in

and around

Tokyo

Taisho 13 (1924)

Kenzabro Kito

proposed Menshin

devices for

buildings (Fig. c) Yamashita

proposed

antiseismic

devices for

buildings (Fig. d)

Showa 2 (1927)

Taro Nakamura

proposed

arrangement for absorption of

energy of seismic

motion (Fig. e)

Showa 3 (1928)

Ryuichi Oka

proposed Menshin

foundation (Fig. f)

-42-
Showa 15 (1940) El Centre earth- quake

Showa 19 (1944)

South East Sea

earthquake

Showa 21 (1946)

South Sea earth- quake

Showa 23 (1948)

Fukui earthquake

Showa 27 (1952)

Off-Tokachi

Earthquake

Showa 9 (1934) 14th special

group established ir\ "Japan

Society for Promotion of

Science" to study seisniic structures

Showa 15 (1940) 14th special

group disbanded

Showa 16 (1941) Standardd for

steel frame structure issued

Showa 19 (1944) Temporary

Japan Standard

Specifications issued:

"Outline of EarthquakeResistant Building Structure"

Showa 23 (1948) Japan

Building Specification 3001

issued structural calculations

for buildings with K = 0.2

Show 26 (1951) Building

Codes in San Francisco

released

Kawasumi published a zoning map for seismic

activity (Kawasumi Map)

Development of SMAC

Showa 25 (1950)

Building

Construction

Rules released

with K = 0.2

Showa 27 (1952)

Zonal coefficients for earthquake

prone area

released

World War II

Show 23 (1948)

Daiwa building

collapsed

Showa 9 (1934)

Kenzabro Majima

patent on seismic

building structure

(Fig- g)

Showa 13 (1938)

Fukuhei Takabeya

proposed dampertype earthquakeresistant structure

(Fig. h)

Showa 26 (1951)

Otsuki proposed a devices for restrict- ing the propagation of earthquake vibrations

(Fig.i)

-43-
Showa 39 (1964)

Niigata earthquake

Showa 43 (1968)

Off-Tokachi

Earthquake

Showa 46 (1971)

San Fernando

earthquake

Showa 31 (1956) The First World Conference on

Earthquake Engineering

held; dynamic studies in full swing

Showa 39 (1964) Design

guidelines for high-rise

buildings propsed

Showa 46 (1971)

Specifications for the design

of reinforced-concrete

building structures modified

Showa 39 (1964)

Restriction on the

height of buildings

(31 m) removed

Showa 46 (1971)

Reinforce- concrete strucutre design standards

modified

Showa 39 (1964)

Liquiefection of earth crust

noticed

Showa 43 (1968)

Reinforced

concrete

buildings

damaged

High-rise

building boom

started

Showa 32 (1957)

Takuji Kobori

published a paper ~ "An experiment

with responsecontrol structures"

Showa 35 (1960)

Takuji Kobori

published a paper — "Analysis of

response control

structures"

Showa 39 (1964)

Senri Katsuta

proposed Menshin

method based on

auto control (Fig. j)

Showa 44 (1969)

Elementary school

at Sc o pj ie

Yugoslavia

Showa 47 (1972)

Development of new

aseismic design started

Showa 48 (1973)

Shigeya

Kawamata

proposed a "mass

pump" (Fig. k)

Showa 52 (1977) New aseismic

design project completed

-44-
Showa 54 (1979)

Off-Miyagi

prefectiire earth- quake

Showa 56 (1981)

Building Standard

Law modified (the

so-called new

aseismic design

method)

Development of

laminated rubber

-45-
IMPORTANT PUBLICATIONS

1891

Kawai, Kozo. 1891. Structures free from the maximum seismic vibratior\s.

Kenchiku Zasshi. No. 60.

1927

Majima, Kenzabro. 1927. On the problem of earthquake-resistant structures.

Kenchiku Zasshi, No. 491.

Sano, Toshiki. 1927. Studies on earthquake-resistant structures. Kenchiku Zasshi,

No. 491.

Nakamura, Taro. 1927. Theory of earthquake resistance from the point of view of

energetics. Kenchiku Zasshi, No. 493

Majima, Kenzabro. 1927. Note on the theories of Dr. Sano about base isolation structures. Kenchiku Zasshi, No. 494.

Nakamura, Taro. 1927. Equipment absorbing the energy of seismic vibrations.

Kenchiku Zasshi, No. 496.

192S

Oka, Ryuichi. 1928. Discussion on the base isolation foundation. Kenchiku Zasshi,

No. 511

1929

Oka, Ryuichi. 1929. Studies on base isolation structures. Kenchiku Zasshi, No. 527

1221

Muto, Kiyoshi. 1931. Doubts in the theory of flexible structures according to Dr.

Sano. Kenchiku Zasshi, No. 543

Majima, Kenzabro. 1931. A rejoinder to Muto's views against the flexible structure

theory. Kenchiku Zasshi, No. 545.

-46-
Naito, Tachu. 1931. Recent trends in antiseismic structures. Kenchiku Zasshi, No.

547.

Sano, Toshiki. 1931. Theory of antiseismic properties. Kenchiku Zasshi, No. 551

Oka, Ryuichi. 1931. Merits and demerits of flexible and stiff structures. Kenchiku

Zasshi, No. 551.

Oka, Ryuichi. 1931. Base isolation and wind-resistant building structures. Kenchiku

Zasshi, No. 552.

1932 .

Oka, Ryuichi. 1932. Merits and demerits of antiseismic flexible and stiff building

structures. Kenchiku Zasshi, No. 556.

1933 '

Oka, Ryuichi. 1933. Theory of base isolation structures. Kenchiku Gakkai Taikai

Ronbun, No 569.

Oka, Ryuichi. 1933. Construction of base isolation foundations. Kenchiku Zasshi,

No. 570

Oka, Ryuichi. 1933. Reply to questions raised by Dr. Tanabe. Kenchiku Zasshi, No.

572.

1935 '

'

Sekine, Yotaro. 1935. Construction of base isolation structures. Kenchiku Zasshi,

No. 600.

1938

Takabeya, Fukuhei. 1938. Damper type earthquake-resistant structures. Kenchiku

Zasshi, No. 636.

Kawasima, Sadao. 1938. Comments on damper-type earthquake-resistant structures

by Dr. Takabeya. Kenchiku Zasshi, No. 638.

Takabeya, Fukuhei. 1938. Further discussions on damper-type earthquake-resistant

structures (Replies to points raised by Sadao Kawasima). Kenchiku Zasshi, No.

640.

Kawasima, Sadao. 1938. On the replies by Dr. Takabeya. Kenchiku Zasshi, No. 641.

-47-
1941

Oka, Ryuichi. 1941. Experiments on roller-type damper-based earthquake-resistant

structures (Experimental studies on the wind-resistant base isolation

structures). Kenchiku Gakkai Ronbun-shu, No 23.

Oka, Ryuichi. 1941. Experimental studies on the base isolation and wind-resistant

structures (Hysteresis curve on a theoretical, reduced-scale model). Kenchiku

Gakkai Rombun-shu, No. 23.

Oka, Ryuichi. 1941. Forced vibrations in a theoretical model of the wind-resistant

base isolation structures (Experimental studies on the wind-resistant base

isolation structures). Kenchiku Gakkai Ronbun-shu, No. 24.

1942

Oka, Ryuichi. 1942. Various properties of theoretical model of wind-resistant base

isolation structures (Experimental studies on wind-resistant base isolation

structures. Part 3). Kenchiku Gakkai Robun-shu, No. 24.

Oka, Ryuichi. 1942. Vibration experiment on a theoretical reduced-scale model of

actual wind-resistant base isolation structures. (Experimental studies on windresistant base isolation structures. Part 6). Kenchiku Gakkai Ronbun-shu, No.

24.

Oka, Ryuichi. 1942. Experimental studies on wind-resistant base isolation structures.

Part 7~Effect of fundamental period of the upper structure. Kenchiku Gakkai

Ronbun-shu, No. 25.

1951

Otsuki, Sizuo. 1951. On the equipment restricting vibration propagation (Damper

Methods). Kenchiku Gakkai Ronbun-shu, No. 42.

1954

Kobori, Takuji and Kiyoshi Kaneta. 1954. A method of imparting antiseismic properties to building structures (Nonresonance method). Kenchiku Gakkai

Kenkyu Hokoku. No. 28.

1956 »

Kobori, Takuji and Ryoichiro Minai. 1956. Nonlinear vibrations in structures due

to earthquake (Part 2. Manual nonlinearization process of dynamic properties

of structures). Kenchiku Gakkai Ronbun-shu, No. 52.

-48-
1957

Sonobe, Yasuhisa. 1957. Studies on vibration control of suspended structures.

Kenchiku Gakkai Ronbun-shu, No. 57.

Kobori, Takuji. 1957 An approach to seismic response control structures. Kenchiku

Gakkai Kenkyu Hokoku, No. 41.

1960

Kobori, Takuji and Ryoichiro Minai. 1960. Analysis of seismic response-control system (Studies on seismic response-control structures. Part 1). Kenchiku Gakkai

Ronbun Hokoku-shu, No. 66.

Kobori, Takuji and Minai. 1960. Requisites for a seismic response-control system

(Studies on seismic response-control structures. Part 2). Kenchiku Gakkai

Ronbun Hokoku-shu, No. 66.

1961

Kobori, Takuji and Ryoichiro Minai. 1961. Analysis of a seismic response-control

system—mass-spring model (Studies on seismic response-control structure. Part

3) . Kenchiku Gakkai Ronbun Hokoku-shu, No. 69.

Kobori, Takuji and Ryoichiro Minai. 1961. Analysis of a seismic response-control

system-mass-spring model (Studies on seismic response-control structure. Part

4). Kenchiku Gakkai Ronbun Hokoku-shu, No. 69.

1964

Katsuta, Chitoshi and Naokazu Masizu. 1964. Studies on response control

structures using automatic control technology. I. Principles and theory.

Kenchiku Gakkai Ronbun Hokoku-shu, No. 102.

Katsuta, Chitoshi; Naokazu Masizu and Hiroshi Uno. 1964. Studies on response

control structures using automatic control technology. II. Experiments and

applications. Kenchiku Gakkai Ronbun Hokoku-shu, No. 102.

Katsuta, Chitoshi; Naokazu Masizu and Hiroshi Uno. 1964. Studies on response

control and vibration isolation by automatic control technology. Kenchiku

Gakkai Ronbun Hokoku-shu, No. 103

Katsuta, Chitoshi; Naokazu Masizu and Hiroshi Uno. 1964. Experimental Studies

on response control and vibration isolation by automatic control technology.

Kenchiku Gakkai Ronbun Hokoku-shu, No. 103.

-49-
1965

Katsuta, Chitoshi and Naokazu Masizu. 1965. Structure of a large-size earthquake

isolation device incorporating electrohydraulic servomechanism. Kenchiku

Gakkai Ronbun Hokoku-shu.

Katsuta, Chitoshi and Naokazu Masizu. 1965. Principle of a large-size earthquake

isolation device incorporating electrohydraulic servomechanism. Kenchiku

Gakkai Ronbun Hokoku-shu.

Matsushita, Kiyoo and Masanori Izumi. 1965. Response control structures as a step

in the direction of earthquake-resistant design of buildings (Part 1). Kenchiku

Gakkai Ronbun Hokoku-shu.

Matsushita, Kiyoo and Masanori Izumi. 1965. Response control structures as a step

in the direction of earthquake-resistant design of buildings (Part 2). Kenchiku

Gakkai Ronbun Hokoku-shu.

1968

Katsuta, Chitoshi and Naokazu Masizu. 1968. Studies on response control method

using servomechanism. Part 3. Stability of servomechanical response control

unit. Kenchiku Gakkai Taikai Kogai-shu.

1973

Kawamata, Shigeya; Mamoru Yoneda and Hirohiko Hangai. 1973. Studies on antiseismic dampers. Part 1. Free vibration experiment and forced vibration

experiment. Todai Seiken Seisan Kenkyu, Vol. 25, No. 3

Kavs^amata, Shigeya; Mamoru Yoneda; Hirohiko Hangai and Kyoko Kanazawa. 1973.

Studies on damping mechanisms. Part 1. Principle and free-vibration experiment. Kenchiku Gakkai Taikai Kogai-shu.

Kawamata, Shigeya; Mamoru Yoneda; Hirohiko Hangai and Kyoko Kanazawa. 1973.

Studies on damping mechanisms. Part 2. Forced vibration experiment.

Kenchiku Gakkai Taikai Kogai-shu.

Kawamata, Shigeya; Mamoru Yoneda; Hirohiko Hangai and Kyoko Kanazawa. 1973.

Studies on damping mechanisms. Part 3. Fundamental oscillation of a system

containing passive mass. Kenchiku Gakkai Taikai Kogai-shu.

-50-
12Z5

Masizu, Naokazu and Toshiaki Kobayashi. 1975. Studies on response control

method using servomechanism. Part 4. Power requirements for operating a response control unit. Kenchiku Gakkai Taikai Kogai-shu.

Izumi, Masanori and Yoici Kishimoto. 1975. Studies on damping methods in

building structures. Tohoku Daigaku Kenchiku Gakuho, No. 16.

1986

Izumi, Masanori. 1986. Base isolation structures today. Kenchiku Gijutsu, April.

Seki, Matsutaro. 1986. History and design application of base isolation structures.

1986 Symposium of the Structural Design Department of Kanto Region of the

Architectural Institute of Japan on Base isolation Structures: Present and

Future.

Kelly, J.M. 1986. History and present state of base isolation structures. Kozoka

Kondan-kai, Structure, No. 20.

Other Publications

History of the development of modern Japanese architecture. Edited by

Architectural Institute of Japan. 1972. Published by Maruzen.

Muramatsu, Teijiro. 1976. History of Modem Japanese Building Technology.

Published by Shokokusha.

Hisada, Toshihiko. 1974. Earthquakes and Architecture. Published by Kashima

Shuppan Kai.

Ohashi, Yuji and Yoji Hashikawa. 1986. Historical review of modifications in the

structural standards from the legal viewpoint. Parts 1 and 2. Kenchiku Gakkai

Taikai Kogai-shu.

Ohashi, Yuji and Shoichi Yamaguchi. 1987. What are base isolation and response

control? Questions and Answers. Kenchiku Gijutsu, May.

-51 -
2.3.2. Examples of response-control structures

The main examples of response-control structures in Japan and other countries are

listed in Table 2.2. They are classified as follows:

1. Computer room-base isolation floor 2 (Japan - 2 cases)

2. Double-column structure 2 (Japan - 1 case)

3. Base isolation structure using laminated rubber 16 (Japan - 10 cases)

4. Dynamic damper 3 (Japan - 1 case)

5. Various damper units 5 (Japan - 2 cases)

6. Others 3

-52-
Table 2.2. Examples of response-control structures in Japan and other countries

No M a m p of

Building

No. of

floors

Floor

2 area m'^

Annlippitinn or Occupancy

Year

ofConstruc- tion

Remarks

(details of

damper)

1 2 3 4 5 6 7 8 9

11 ivi .I.e. r 1 u u r system

v_,oiTipucer room floor

R^11 V* l'^ T\ CT Ddll ucdlllli^ support

Z Dynamic floor -do- Teflon sheets

3 Fudochokin

Bank (now

Kyowa Bank)

Himeji

bhimonoseki

+3,-1

+3

791

641

RC

KC

Bank branch

-do19341934

Sway-type

hinged

column

4 Tokyo Science

University

Tokyo +17,-1 14,436 Steel School 1981 Double

columns

5 Union House Auckland, New

Zealand

+12,-1 RC Office 1984 -do6 Pestalochi

Elementary

School

Skopjie,

Yugoslavia

+3 RC School 1969 Rubber

7 Foothill Law

and Justice

Center

California, USA +4,-1 Steel Court 1986 Laminated

rubber

8 W. Clayton

Building

Wellington,

New Zealand

-t4 RC Office 1983 Laminated

rubber

9 Cruas Atomic

Power Plant France RC Atomic

furnace

1984 -do10 Koeberg

Atomic Power

Plant

South Africa RC -do- 1983 -do11 Yachiyodai

Apartments

Chiba, Japan +2 114 RC Housing 1983 -do12 Okumura

Cumi, Tsukuba

Research

Center, office wing

Ibaraki, Japan +3 1,330 RC Research

Center

1986 -do13 Tohoku

University,

Shimizu

Construction

Laboratory

Miyagi, Japan +3 200 RC Observatory 1986 Laminated

rubber, oil damper

-53-
1 2 3 4 5 7 8 9 14 Obayashi

Corporation,

Technical

Research

Center, 61st

Laboratory

Tokyo +5,-1 1,624 RC Laboratory 1986 Laminated

rubber

15 Oiles

Industries

Technical

Center,

Fujisawa Plant,

TC wing

Kanagawa,

Japan

4,765 RC Laboratory,

Office

1986 -do16 Funabashi

Taketomo

Dormitory

Chiba, Japan +3 1,530 RC Dormitory 1987 -do17 Kajima

Institute of

Construction

Technology,

Acoustic

Laboratory

Tokyo +2 655 RC Research

Laboratory

1986 -do18 Christian

Museum

Kanagawa,

Japan

+2 293 RC Museum Laminated

rubber

19 Chiba Port

Tower

Chiba, Japan 125 m 2,308 Steel Tower 1986 Dynamic

damper

20 Sydney Tower Australia 325 m Steel Tower 1975 -do21 City Corp.

Center

New York, USA +59 Steel Office 1977 Tuned mass damper

22 Hitachi

Headquarters

Tokyo +20,-3 57,487 Steel Office 1983 Steel damper

23 World Trade

Center

New York, USA +110 Steel Office 1976 VEM damper

(visco-elastic

material)

24 Columbia

Center

Seattle, USA +76 Steel Office 1985 -do25 Radar

Construction

Chiba, Japan Steel Instrument

platform

1980 Roller bearing

26 Christchurch

Chimney

Christchurch,

New Zealand

35 m RC Chimney Steel damper

27 Commerce and

Industry

Culture Center

Saitama, Japan +30 Steel Office 1987 Friction damper
1 2 3 4 5 6 7 8 9 28 Fujita

Industries

Technical

Research

Laboratory,

(6th

Laboratory)

Kanagawa,

Japan

+3 3,952 RC Research

center

•

Laminated

rubber

29 Shibuya

Shimizu No. 1 Building

Tokyo +5,-1 3,385 RC Office -do30 Fukumiya

Apartments

Tokyo 682 RC Apartment -do31 Lambesc C.E.S. France +3 4,950 Precast RC

School 1978 -doNote: + indicates floors above ground; and - indicates floors below ground.

Table 2.3a. Cases approved by the Ministry of Construction (1)

Item

(0)

Yachiyodai Apartments

(1)

Christian Museum

(2)

Okumura Gumi, Tsukuba

Research Center

1 2 3 4

Designed by Tokyo Kenchiku

Structural Engineers

Tokyo Kenchiku

Structural Engineers,

Unitika

Tokyo Kenchiku

Structural Engineers,

Okumura Inc.

Design requirements Antiseismic. Prevent

any damage to goods

stored

Antiseismic. Protect

computer and stored

data. Measurement of

response for technical

studies

Appraisal No. BCJ LC 99 BCJ Menl BCJMen2

Year of Appraisal April 1982 July 1985 November 1985

Year of approval; No. November 2, 1982; 455 November 19, 1985; Kana

61

December 24, 1985

Tochi 37

No. of stories +2 +2, -1 +4

Total floor area, m^ 60.18 226.21 348.18

Occupancy Housing (residential) Museum Research center

-55-
Structure RC frame and shear wall RC frame and shear wall RC frame

Foundation Raft foundation with

cast in-situ piles

Deep foundation RC cast in-situ raft

Isolator: Dimensions,

mm

82 X 300 dia Rubber 5 thick x 300 dia

(12 layers)

Rubber 7 thick x 500 dia

(14 layers)

Numbers 6 32 25

Bearing

Capacity

cr = 45 kg/cm^, 0.5 t/cm

(32 t)

(T = 60 kg/cm2 0.5 t/cm

(42.5 t) d = 60 kg/cm^, 0.86 t/cm(120 t)

Damper Friction force between PC

plates

Uses plastic deformation

of steel bars bent to make

a loop (8 Nos.)

Uses plastic deformation

of steel bars bent to make

a loop (12 Nos.)

Base-shear

coefficient used in

design

0.2

•

0.15 0.15

Fundamental period

a t Small

deformation

1.83 sec 1.4 sec 1.4 sec

a t Large

deformation

1.9 sec 2.1 sec

Input seismic wave El Centro 1940 (NS)

Hachinohe 1968 (NS)

Hachinohe 1968 (EW)

Taft 1952 (EW)

El Centro 1940 (NS)

Hachinohe 1968 (NS)

Taft 1952 (EW)

El Centro 1940 (NS)

Taft 1952 (EW)

Hachinohe 1968 (NS)

Input level 300 gal 300 gal, 450 gal 300 gal, 450 gal

-56-
Table 2.3b. Cases approved by the Ministry of Construction (2)

Item

(3)

Obayashi Co. Technical

Research Center

(4)

Oiles Technical Center,

Fujisawa Plant, TC wing

(5)

Funabashi Taketomo

Dormitorv

1 2 3 4

Designed by Obayashi Corporation Oiles Industries,

Sumitomo Constructions

Yasui Building Designers

Takenaka Corporation

Design requirements Antiseismic. Protection

of computer and other

laboratorv eouinmpnt

Antiseismic. Protection

of computer and other

laboratorv pniiinmpnt

Stored.

Safety and damage

mitigation during

parthmiakp ^ Cll LI LU u ur^VAppraisal No. BCJ Men3 BCJ Men4 BCJ Mens

Year of Annraisal Februarv 1986 March 1986 Anril 1986

Year of approval; No. February 27, 1986; Tok.

30

April 7, 1986; Kana 21 Tune 24 1986- Chi 43

No. of stories +5 +5 +3

Total floor area, m^ 351.92 1136.5 719.28

Occupancy Laboratory Research laboratory and

office

Dormitory

Strurture RC RC RC

Foundation PHC pile (cement grout

method)

Concrete in-situ raft

(earth-drilling method)

Concrete in-situ raft

(earth-drilling method)

Isolator: Dimensions, rrm Rubber 4.4 thick x 740

dia (61 layers)

Rubber 10 thick x 24

layer (H = 363), OD =

650, 700, 750, 800

Rubber 7 thick x 670 dia

(19 layers) (H = 187)

Rubber 8 thick x 700 dia

(18 layers) (H = 195)

Numbers 14 35 14

Bearing

Capacity

200 t 200 t-^ 6 Nos.

150 t ^ 8 Nos.

Damper Uses elasto-plastic

hystersis of steel bars (96

Nos.)

Lead plug inserted in

laminated rubber

Vicous damper (8 Nos.)

-57-
Base-shear

coefficient used in

design

0.15 0.2 0.15

Fundamental period

a t Small

deformation

X = 1.33 sec Y = 1.24 sec X = 0.895 sec: Y = 0.908

sec (at 50% deflection)

X = 2.09 sec

a t Large

deformation

X = 3.12

Y = 3.08 sec X = 2.143 sec: Y = 2.148

sec (at 100% deflection)

Y = 2.10 sec

Input seismic wave El Centro 1940 (NS)

Hachinohe 1968 (NS)

Hachinohe 1968 (EW)

Taft 1952 (EW)

El Centro 1940 (NS)

Hachinohe 1968 (NS)

Hachinohe 1968 (EW)

Taft 1952 (EW)

KT 008 1980 (NS)

El Centro 1940 (NS)

Taft 1952 (EW)

Tokyo 101 1956 (NS)

Hachinohe 1968 (NS)

Man-made earthquake

2 waves Man-made earthquake

2 waves Man-made earthquake4 waves

Input level 25 cm/sec, 50 cm/sec 25 cm/sec, 50 cm/sec 25 cm/sec, 50 cm/sec

Table 2.3c. Cases approved by the Ministry of Construction (3)

Item

(6)

Acoustic & Environmental Vibration Test Laboratory, Kajima

Corporation

(7)

Christian Museum

(reapplied)

(8)

Fukumiya Apartments

1 2 3

Designed by Kajima Corporation Tokyo Kenchiku

Structural Engineers

Okumura Inc.

Design requirements Reduce seismic input and

insulate (isolate) from

microtremor of ground

Antiseismic. Prevent

any damage to stored

goods

Safety of building.

Added value in business

Appraisal No. BCJ Men6 BCJ Men7 BCJMenS

Year of Appraisal May 1986 July 1986 December 1986

Year of approval; No. December 5, 1986; Tok

473

March 3, 1987; Tok 44

No. of stories +2 +2 +4

-58-
Total floor area, 379.10 - - 149.43 225.40

Occupancy Research Laboratory Museum Apartment housing

Structure RC RC RC

Foundation Concrete in-situ raft

(deep foundation)

Deep foundation Concrete in-situ raft

(miniature earthdrilling

method)

Isolator: Dimensions, rrm 320H X 1340 dia (48 thick

X D layer;; c5UoH x lUoU

dia (38 thick x 6 layer)

4 thick x 435 dia (25

layers)

7 thick X 500 dia (14 & 16

layers)

Numbers 18 12 12

Bearing

Capacity

165 t: 1340 dia

100 t: 1080 dia

0- = 60 kg/cm^; 0.55 t/cm

(90 t)

ThJlilcloliJ 1 a c fro — Kil pia&llL a c4"i rf^ Uctliipt:! ^mnoir

using mild steel bars (14

Nos.)

of steel bars bent to make

a loop (6 Nos.)

ubcb pidbtiL Uciuriiicitiuri of steel bars bent to make

a loop (7 Nos.)

Base-shear

coefficient used in

design

0.2 0.15 0.2

Fundamental period

a t Small

deformation

X: 0.828 sec

Y: 0.809 sec

1.3 sec 1.4 sec

a t Large

deformation

1.80 sec 1.9 sec 2.2 sec

Input seismic wave El Centro 1940 (NS)

Taft 1952 (EW)

Tokyo 101 1956 (NS)

Sendai 1978 (EW)

TH038-1

El Centro 1940 (NS)

Taft 1952 (EW)

Hachinohe 1968 (NS)

El Centro 1940 (NS)

Taft 1952 (EW)

Tokyo 101 1956 (NS)

Hachinohe 1968 (NS)

Input level 25 cm/sec, 50 cm/sec 300 gal, 450 gal 25 cm/sec, 50 cm/sec

-59-
Table 2.3d. Cases approved by the Ministry of Construction (4)

Item

(9)

Shibuya Shimizu Building

No. 1

(10)

Fujita Industries No. 6

Laboratory

1 2 3

Designed by Obayashi Corporation Fujita Industries

Design requirements Protect the main building

and OA equipment installed

therein

Protect the main building

and equipment stored

therein such as laboratory

equipment, computers

Appraisal No. BCJ Men9 BCJ MenlO

Year of Appraisal February 1987 February 1987

Year of approval; No. March 13, 1987; Tok 52 May 14, 1987; Kana 23

No. of Stories +5, -1 +3

Total floor area, m^ 560.30 102.21

Occupancy Office Research laboratory

Structure RC RC

Foundation Concrete in-situ raft (earthdrilling method)

PHC pile (type A, B)

Cement milk method

Isolator: Dimensions, mm 5.0 thick X 620 dia (50 layers);

6.0 thick X 740 dia (45 layers)

4.0 thick X 450 dia (44 layers)

Numbers 20 4

Bearing capacity 100 - 150 t : 620 dia

200 - 250 t

• 740 dia

Damper Elasto-plastic damper using

mild steel bars (108 Nos.)

Base-shear coefficient used in

design

0.15 : Basement, 1st floor;

0.183 : 3rd floor; 0.205 : 5th

floor

0.15 : 1st floor, 0.17 : 2nd

floor; 0.20 : 3rd floor

-60-
Fundamental period at: Small deformation X = 1.30 sec; Y= 1.24 sec 1.35 sec

Large deformation X = 2.99 sec; Y = 2.97 sec

Input seismic waves El Centro 1940 (NS)

Taft 1952 (EW)

Hachinohe 1968 (NS)

1 IdClllllUllt: lyOO \1-jV\ J SDKANRIG Man-made

SDKANTIG seismic

SDANSRIG waves

El Centro 1940 (NS)

Taft 1952 (EW)

Hachinohe 1968 (NS)

Harhinnhp 1968 CFW)

ARTM79L00 (simulated

seismic wave)

Input level 25 cm/sec, 50 cm/sec 25 cm/sec, 50 cm/sec

Table 2.3e. Cases approved by the Ministry of Construction (4)

Item

(11)

Inorganic Material Research

Institute, Vibration-free

Wing

(12)

Shimizu Corporation

Tuchiura Branch Building

1 z. o

Designed by Secretariat of the Ministry of

Construction, Planning

Bureau, Obayashi

Corporation

Shimizu Corporation

Design requirements Protect the main building

and research equipment

stored therein

Appraisal No. BCJMenll BCJ Menl2

Year of Appraisal June 1987 June 1987

Year of approval; No.

No. of Stories +1 +4

Total floor area, m^ 8,341 (old ~ 7,725; new ~ 616) 170.366

Occupancy Research laboratory Office, dormitory

Structure RC RC

-61 -
Foundation PHC raft (type A) Blast

method

PHC raft (type B, C) using

earth auger method

Isolator: Dimensions, mm 3.2 thick X 420 dia (62 layers) 6.0 thick X 450 dia; 6.0 x 500;

6.0 X 550 (31 layers)

Numbers 32 14

Bearing capacity 65 t (max 80 t) 51 -165 t

Damper Elasto-plastic damper using

mild steel bars (48 Nos.)

Lead plug inserted in the

center of laminated rubber

Base-shear coefficient used in

design

0.15 All floors 0.15

Fundamental period at: Small deformation

Large deformation

X = 1.17 sec Y= 1.17 sec X = 2.26 sec Y = 2.26 sec

X = 0.77 sec Y = 0.77 sec X = 2.33 sec Y = 2.33 sec

Input seismic waves El Centro 1940 (NS)

Taft 1952 (EW)

Hachinohe 1968 (NS)

Hachinohe 1968 (EW)

Tsukuba 1985 (NS)

Tsukuba 1985 (EW)

Tsukuba 1986 (NS ) Tsukuba 1986 (EW)

El Centro 1940 (NS)

Taft 1952 (EW)

Hachinohe 1968 (NS)

Ibaragi 606 1964 (NS)

Input level 25 cm/sec, 50 cm/sec 25 cm/sec, 50 cm/sec

-62-
2.3.3. Cases approved by the Ministry of Construction

More than ten base isolation structures using laminated rubber have been approved

by the Ministry of Construction, Yachiyodai Apartments being the first. These are

listed in greater detail in Table 2.3.

2.3.4. Trends in other fields

So far v^e have discussed proposals for response-control structures mainly in building construction: examples of buildings constructed using these techniques and some

cases approved by the Ministry of Construction. We now review the trends in the

field of civil construction and mechanical engineering in Japan and the directions of

future technological developments and current norms in other countries.

1. Trends in Japan in other fields

1. National Railways

In 1961, chloroprene rubber pads were used to support the girders in the

railway bridge on Kinugawa River on the Tohoku trunk route. In 1972, a book on the use of rubber shoes on the concrete raUway bridge was published;

this is widely referred to for bridges on the conventional trunk lines as well as the Shinkansen (Bullet train) track. In addition, a book caUed Construction of

Railway Bridge Supports has also been prepared.

2. Road Bridges

The Japan Roads Association has published such books as Bearing Handbook

and Standard Design for Road Bridge Bearings to promote the design of

rubber bearings. There are many examples of the use of rubber supports as pads. Studies continue on base isolation structures for road bridges by the

Public Works Research Institute of the Ministry of Construction and Road

Corporation. Presently, studies on laminated rubber bearings have just been

completed at the Public Works Research Institute.

3. Electric Power Supply Industries

i) Denryoku Central Research Laboratory

*Study on "lead plug" is in progress jointly with EPRI;

^Conducted forced-vibration tests on base isolation buildings of Okumura Inc. and Giles Industries (1986, 1987);

*Base isolation floor is being developed;

* Base isolation method for machinery is being developed.

-63-
ii) Electric Power Supply companies, (nine companies) and Japan Nuclear

Power Co.

*Phase I (April 1985-March 1987) of joint studies by electric power supply

companies (mentioned above) is over and Phase II wiU start;

^Studies on the application of base isolation technique to transformer are in

progress;

*Studies about base isolation structure for FBR-type atomic furnaces are underway. Cases of Super Phoenix FBR base isolation building in France etc. are referred. Prof. Shibata and Assistant Prof. Fujita of the Institute of

Industrial Science at Tokyo University are in charge of these studies.

*Others

Development of devices and components and application tests are underway

in such fields as machinery, pipelines, boiler structure, building structures

and tanks.

Trends overseas

1. USA

Guidelines for base isolation design (proposed) are being prepared in North

California, but this is considered a local document. These guidelines are being prepared by the Seismology Committee of the Association of Structural

Designers, North California. Persons such as J.M. Kelly are also invited to participate. The document intends to consider specifications in great detail.

2. New Zealand

The design standard for reinforced concrete structure briefly discusses the base

isolation structure. According to this standard, there is not much scope for

future development of this technique and as such cursorily mentions its merits or the relationship between the input level and the behavior of the

entire structure. It notes that some standardization can be expected as the

number of such buildings increases.

3. Examples of response-control structures against wind

There are many examples of controlling vibrations due to wind. The City

Corp Center in New York is one such example. Response-control against

winds is also done in civil engineering structures and machinery. The list of

examples of response-control against winds compiled by Matsuo Tsuji is given in Appendix 2 for reference.

-64-
CHAPTER 3

POSSIBLE APPLICATIONS OF RESPONSE-CONTROL STRUCTURES

3.1. Improvement in Building Design by Using Response-control Techniques

3.1.1. Areas of Application

Damper techniques may be used for the entire building or for the equipment placed

inside the building. The response-control technique may be employed for the

following broad categories:

1. Instruments or equipment kept inside the building.

2. Structural elements (such as floors or beams).

3. The entire structure.

The concept or response-control may be explained schematically for all these

cases as shown below:

03

/////////////// /////////////// V7///////////.

Response-control

of

equipment

Response-control

of

floors

Response-control

of

the entire structure

3.1.2. External turbulence as objectives of response-control

The response-control technique can be used for both types of external turbulence:

vibrations due to natural phenomena and vibrations due to anthropogenic

phenomena. These can be further classified according to the amplitude and

direction of the vibrations.

1. Types of Vibrations

a Microtremor (continuous or frequent vibrations of small amplitude due

to traffic, vibrations due to people walking or working, machine

vibrations, and vibrations due to construction activity).

-65-
b. Normal wind.

c. Moderate earthquake.

d. Typhoon.

e. Severe earthquake.

2. Direction of vibrations

a. Horizontal. ' -

b. Vertical.

The range of permissible vibrations generated in a public building due to different types of external forces or the level of vibrations in special purpose

buildings such as the "clean room" in a semiconductor-manufacturing plant

is shown in Fig. 3.1. Here the vertical axis represents the horizontal

acceleration due to external force while the horizontal axis shows the

fundamental frequency of buildings.

3.1.3. Improvement in the quality of design

The response-control technique restricts or controls the response of buildings to external vibrations. The response to be restricted or controlled is for acceleration, velocity and displacement. It is possible to control or restrict the stresses developed in

structural material by controlling the above responses.

-66-
1000

O ^

«P5 1-^ u

u

<

<

H

2

O

Nl-H o

O

<

2

U

H

X

o

H

W

D

Q

100

10

0.1

Vibrations in a building with

long period due

to severe earthquake

Vibrations in a building with

long period due

to moderate

earthquake and

wind

Vibrations in a low or medium height building

due to severe earthquake

Vibrations in a low or medium height building

due to moderate earthquake

Vibrations of the ground

Vibrations such as cause

living harassment

Permissible vibrations

in a clean room

0.1 10

FUNDAMENTAL FREQUENCY OF BUILDINGS ( Hz )

Fig. 3.1. The range of vibrations developed in a building due to external forces and

the vibration sensitivity range for buildings in different applications.

The extent of restriction or control of response of buildings to external forces using

response-control techniques can be set at any level, unlike in earlier wind and

earthquake-resistant structural design methods. As a result, the response-control

technique is most effective in solving the technical problems encountered during

design, which are mentioned below:

-67-
1. Ensuring safety of structures under emergency conditions. -

2. Reduction in the cross-sectional area of structural elements

3. Preventing vibrations, sliding or rolling of furnitures.

4. Preventing damage or peeling of nonstructural elements.

5. Restricting uncomfortable vibrations.

6. Maintaining nonerratic performance of machines and gadgets.

Earlier such design had to be carried out under several technological constraints.

If response-control technique is used judiciously in the design of a building,

safety, economy, machine performance, working comforts, living comforts in

buildings can easily be ensured. Today it is possible to design a building having

much of those added profits.

3.2, Applications of this Technique

As mentioned in Section 3.1, the response-control structure can be used to overcome

various technical problems. Accordingly, it increases the value (utility) of the building structure. Applications of the response-control structures and the major problems therein are listed in Table 3.2.

The pubUc buildings or building used at a time of disasters should be particularly safe

v^ith respect to earthquakes. When art galleries or museums house valuable exhibits, adequate protection must be provided.

In the case of a nuclear power plant, lifeline facilities or modem industrial facilities,

the safety of a building and it contents against earthquakes is very essential. Also, if there is a possibility of hazardous discharge,then the response-control structure can be used to control such discharge. Particularly in modern industrial facilities such as an IC manufacturing factory, it is necessary to restrict the normal vibrations to very

low levels and the response-control structure, in this case, can be used to ensure proper functioning.

-68-
Table 3.2. Performance requirements and merits in various applications of response control

structures in buildings

Effect/ Housing General Public Building Art gallery/ Atomic Life line LeadingTechnical office building essential museums power facility edge

theme building at facility facility industrial hazardous facility

conditions

I 2 3 4 5 6 7 8 9

1. Ensure Safe Safe Safe Safe Safe Safe Safe Safe

building

structure

Z.. 9 PnpYiViiiifv X iCAJ.L'lllty J_.CLf ILV-'llLy / inill Hp^icm U.C.9it:iiL r»f design

Oil LK.IL11CH rl PY1 Viil if\7 iiCA.lUllJ.Ly t1 PY1 Vi 1 1

1

iiCAJ.L'lllLy elements

Dale

• DatiS"• satis- satis- fn-I- oI"f 1 rLittJCi csatis- vibrations factory factory factory the the the factory

sliding. perfor- perfor- perfor- exhibits contents. contents. perforTollino" of in11 idia n pp ma n rp m a n fp Satis- Satis- in a nrp

contents factory factory Prevent

perfor- perfor- hazardous

iiidin-e. Prevent Prevent

hazar- hazarcharge charge

Satis- Satis- f 1 C- Q:af 1 C- i»?ClLl& damage to economy. economy. factory factory factory factory factory factory non- design design perfor- perfor- perfor- perfor- perfor- perforIlcAlUlllLy IlcAlUlllly illclilv.c IlLcliLL.t; elements

5. Restriction Satis- Satis- Satis- of factory factory factory

uncomfor- living living living

table conditions conditions conditions

vibrations

6. Maintain Satis- Satis- Satis- proper factory factory factory

functioning perfor- perfor- perfor- of mance macne mance

machinery.

equipment.

etc.

-69-
CHAPTER 4

VARIOUS ASPECTS OF RESPONSE-CONTROL STRUCTURES

In this chapter we discuss those problems which need to be solved so that the responsecontrol technique can be fully developed as a practical technique in the future and widely

accepted. In Section 4.1, we discuss the technical aspects and in Section 4.2, the statutory

aspect. The following points are covered in Section 4.1.

1. External turbulence

2. Methods of dynamic analysis

3. Design methods

4. Equipment

5. Construction

6. Maintenance

The structures reviewed in this section are basically response-control structures. However,

our discussion of the six main points will lay more stress on Menshin structures using base

isolation. Current progress of technical development or the results of application of these

techniques to actual buildings are also considered.

4.1. Topics for Future Technical Development

1. External Turbulence

1. Evaluation of seismic ground motion

The earthquake resistance of a response-control structure depends on the

precision and reliability in controlling its response to earthquakes.

Evaluation of these properties depends on the correct evaluation of seismic

ground motion which is assumed during design of an oscillating system.

Therefore how to suppose the level and dynamic properties of incident

seismic ground motion is the most important part of the design process. Here

we shall discuss the problems in fixing the level and properties of such

seismic ground motion during the design of a base isolation structure.

Recently, the Building Center of Japan has published a report entitled Seismic

Motion for Dynamic Analysis of Multistoried Buildings in which the views

of the High-rise Building Technical Appraisal Committee about the guideline

for seismic response analysis in seismic design of multistoried buildings are mentioned. According to the Committee's report:

-70-
1. The intensity of an earthquake to be used in seismic response analysis of

high-rise buildings should be set in two stages. Level 1 and Level 2. While

designing a building v^^hich is supported on Tokyo's gravelly soil layer, the

maximum velocity of seismic ground motion, under each level, should

be assumed to be 25 cm/sec and 50 cm/sec, respectively.

2. In the case of seismic response analysis, the v^ave form of seismic ground

motion should be of more than three types, including at least one each of: (a) the standard waveform (El Centro (NS), Taft (EW); (b) the waveform

considering the soil properties at and around the site of construction (for

example, Tokyo 101, Osaka 205); and (c) the waveform incorporating a long-period component (Hachinohe, etc).

3. The main structural frame should be in the elastic range for the Level 1 seismic ground motion, while in case of the Level 2 seismic ground

motion there can be no such damage to the structure, which may cause

injuries to human beings.

Presently, construction of base isolation buildings must be approved by the

Ministry of Construction after the design is evaluated by the Building Center

of Japan (BCJ). The BCJ usually insists that the design of a base isolation

structure be carried out in accordance with the guideline mentioned above for

high-rise buildings.

However, the base isolation structure shows totally different behavior than

that of high-rise buildings although its fundamental period may be similar.

The major difference is that the response displacement is concentrated in the

base isolation device and any propagation of energy to the upper portion is restricted. Accordingly, it seems desirable to study the seismic ground motion

for the base isolation structure design and to look again at the design

guideline.

While considering the incident seismic ground motion, we must note that

the displacement is concentrated in the region of the base isolation device. In

addition, we must consider the seismic ground motion with a comparatively

long period and the effect of difference in the properties of the foundation

strata. Also, we should consider the effect of vertical seismic motion on these

buildings. And we must also consider that the direction of seismic ground

motion does not necessarily coincide with the principal axis of the structure.

-71-
2. Evaluation of Wind Effects

The wind is broadly divided into tv^o categories: mild breeze which flow

every day (hereafter referred to as normal wind) and strong winds, for

example typhoons with an average wind velocity of 20 m/sec or higher. In

the normal wind, the sway of a building may be a problem in terms of

comfortable living conditions, while for strong winds such as typhoons, the

sway may be a problem in terms of structural safety.

The response control for living comforts must be studied from various

perspectives such as studying the properties of normal wind, methods of

modelling building structure, methods of response analysis, and evaluation

of living comforts. ^

The properties of wind force differ from those of the seismic force. Therefore,

it is meaningless to consider the incident wind wave in a time domain.

Hence the analysis as well as evaluation have to be made in the frequency

domain. For the evaluation criteria for living comforts, various proposals

have been offered such as the ISO standard wherein evaluation is made on

the basis of response acceleration in the frequency domain. All these

proposals should be reviewed.

3. Evaluation of Microtremor

It has been reported that base isolation structures using laminated rubber

bearings are effective even in eliminating microtremor of ground.

Various factors cause microtremor: traffics, construction works, etc. The

amplitude of such vibrations ranges from a few tens of ]im to few hundred

]im when there are several sources of vibrations. If there are only a few

sources, the amplitude of vibration is small, a few )im. The frequency range is wide: 0.2- 0.5 Hz to about 100 Hz. It used to be comparatively easy to damp

high-frequency vibrations above 10 Hz, but vibration of 1 - 10 Hz frequency

were not easy to eliminate. In a base isolation structure, since the

fundamental frequency is 0.3 - 1 Hz, damping of these microtremors is easy

between 1 and 10 Hz. However, the microtremor of very low frequency (0.3 -

1 Hz) cannot be eliminated.

For the purpose of designing a base isolation structure, problems arise in

methods for measurement and analysis of microtremor in the low frequency

region, methods for the damping of microtremor of very low frequency,

methods for evaluation of energy dissipation at a surface between foundation

and subsoil, etc. »

Such a technique for restricting or controlling the external microtremor is useful not only for improvement of living conditions but for production

facilities which do not allow for microseisms. When applying such a technique to production facilities, it is necessary to reexamine the properties

-72-
of microtremor related to the requirements of the production facilities in

addition to the problems mentioned above.

2. Dynamic Analysis Method

1. Analytical model of structures

i) Base isolation structure

In case of a base isolation structure, the stiffness of the device portion is much

less than the stiffness of the upper structure. Hence, the dynamic properties

of the base isolation structure generally conform to the dynamic properties of a rigid body supported on a spring. It is thus possible to represent the base

isolation structure as a nonlinear multi-degree-of-freedom single-mass

system. Using this model, we can study the variation in response quanta by

changing the parameters such as: a) nonlinear properties of various types of

dampers; b) torsional vibrational properties; c) response properties to multidimensional inputs; and d) rocking response considering vertical

stiffness of laminated rubber.

The response of such a nonlinear system can be evaluated in terms of an

equivalent linear model. If we could know the universal method for

supposing such an equivalent linear model, it would be very useful for the

design of base isolation structures.

Further studies on the effect of nonlinearity in stiffness and damping of base

isolation devices on the response of base isolation structures wiU be necessary

to get such methods.

ii) Response-control structures (excluding the base isolation structures)

The response characteristics of response-control structures (excluding the base

isolation structures) can roughly be inferred from the properties of

fundamental mode of oscillation of simplified structure models.

For example, in case of added-mass type response-control structures, we can assume a two-mass system model, where the added mass is supposed to be

one of the two masses. Analyzing this model, we can know the effect of the

added-mass damper: in case of a tuned-mass-damper system, the effect can be

evaluated in terms of the equivalent damping force of the total system, and in case of an active-mass-damper system, it is evaluated in the same way

assuming the control force supplied to the system is equivalent to damping

force.

In case of structures equipped with dampers using nonlinear mechanical

properties of materials, friction resistance, etc., we can analyze their response

by assuming that those dampers have damping properties proportional to the

accumulated strain energy, and then we can know the effect of dampers in

terms of the equivalent damping force.

-73-
Since the response-control structures under consideration appeared more

recently than the base isolation structures did, knowledge and data on their

effect are not yet complete. Therefore, in designing response-control

structures, analyses on such simplified models as stated above will be useful

to obtain rough knowledge on the effect of major factors before making

detailed analyses on full structures.

2. Techniques for dynamic analysis on wind effects

Current practical methods for wind-resistant design do not adequately

evaluate the effect of spatio-temporal fluctuation in wind pressure. To

restrict or control the response to strong winds when using response-control

techniques, it is necessary to consider the spatio-temporal fluctuation in wind

pressure. While estimating the relationship between wind pressure and

building structure response, we cannot determine the response in the time

domain as in the case of earthquake response analysis: it is also necessary to study the response using statistical methods in the frequency domain which

include the consideration on aerodynamical and structural properties of the

building. In that case, a particular consideration should be taken on the fact

that the time (instant) at which the maximum wind pressure is generated at each point on the wall surfaces of a structure is not simultaneous.

Design Method

1. Specifying the design criteria

The design criteria include the information on controlling the vibrations of a building to a particular level. These vibrations are generated in response to temporary external force, such as a severe earthquake or typhoon, or other

normal external forces such as traffic vibrations, normal winds or small

earthquakes. The level is determined according to the use, type of structure

and location of the building. Establishment of guidelines for specifying the

design criteria would be a significant contribution to the promotion of

development of this technique.

In conventional buildings, structures are so designed that moderate

earthquakes which occur at a higher frequency cause no damage and the

structure may suffer some damage under the impact of a severe earthquake,

but this damage should be so controlled that human life is not endangered.

On the other hand, in the case of response-control structures, the design

criteria must be established so that not only are any damages to the building

structure avoided, but the entire building, including the things or equipment

inside, is protected. Furthermore, the additional design criteria for normal

turbulence should be set after considering various aspects such as living

comforts and the operation of precision instruments.

-74-
2. Static design methods for structures

The main object of the response-control structure is to reduce the seismic

response acceleration so that the seismic force to be assumed for structural

design purposes is reduced. However, under the present regulations, we

cannot reduce the level of seismic force by more than 75% of the seismic force

level to be assumed for ordinary buildings. In the case of Menshin structures,

using base isolation, it is possible to greatly reduce the acceleration response of

structures and hence a review of the above cited lower limits is needed.

If it is possible to greatly reduce the seismic force by providing a base isolation

device, it will be possible to construct new types of buildings such as high-rise,

long-span reinforced concrete buUdings, high-rise masonry buildings, etc.

3. Accuracy in response prediction

The mass of the actual structure, its dynamic properties or the various

properties of devices used may not be the same as those assumed during the

design state. It is therefore necessary to consider all possible uncertainties in

the elements constituting an oscillating system. In any case, the development

of a simple method for designing response-control or base isolation structures

wherein the consideration on the uncertainty are minimized as much as possible is required to make this technique popular.

4. Design methods for non-structural elements and equipment

Use of the response-control structure generally reduces the response

acceleration and relative story displacement of the structure. As a result, the

force acting on the non-structural elements and equipment is decreased and

in addition difference in the amount of forces acting them at each story

becomes small. We can expect, thus, to rationalize the design of these

elements and equipment . In the case of Menshin structures using the baseisolation method, however, a relative displacement of about 20 to 30 cm

between the earth's crust and the structure can occur during a severe

earthquake. In this case the design of non-structural elements and equipment

has to allow for deformation. Adequate technology has not yet been

developed but is clearly needed.

Safeguarding the equipment/instruments installed inside a building, beyond

simply avoiding physical damage due to rolling during an earthquake, is essential when it is important to ensure that there is no error developed

during the operation and that their performance is unaffected. It thus

becomes necessary to evaluate the seismic response of such instruments as well as of the floor slabs to understand these aspects. Simultaneously, it is necessary to develop sophisticated analytical techniques.

-75-
5. Evaluation of the ultimate condition

Considering that the input seismic motion used in design does not represent

the full nature of incident earthquakes, the evaluation of the ultimate safety

of response-control or base isolation devices is difficult. Today, in the case of

Menshin structures using the base-isolation method, the ultimate safety is evaluated assuming earthquake ground motions of the same magnitude and

property as that considered during design of very tall buildings. However,

there is currently no uniform approach for determining the ultimate

condition during an earthquake with intensities higher than those assumed

during design.

In ordinary buildings, the structure is made strong enough to ensure safety

even at higher loads. What part of the response-control structures

correspond to this extra power? Many proposals have been offered for safer

design. They include assuming a higher level of seismic forces during design

or installing fail-safe devices or backup devices. However, this topic needs

immediate further study.

Response-Control Device

1. Structural properties of the device

Physical properties

Certain experiments can be conducted to objectively evaluate properties of a device. Since these devices are complex bodies with different structures, the

experiments should reveal first the properties of raw materials, the

performance and characteristics of each element and finally the characteristics

of devices taken as a whole. More specifically, deformation properties and

deformation-stiffness properties or energy-absorption properties can be

evaluated. Evaluation of these parameters should ensure the safety of

response-control structure.

Development and standardization of testing methods

The properties and characteristics of response-control devices will vary

according to the type. Accordingly, some variety in test methods is necessary

to test different properties. Some common standards must be established to ascertain the performance on these devices.

2. Evaluation methods for durability of devices

Evaluation and methods

Various methods of evaluation can be used. Some items can be evaluated

according to a method specified by the Japanese Industrial Standards, some

according to other evaluation methods. Anyway, we must select adequate

-76-
evaluation items and evaluation methods based on common standards to guarantee the desired performances.

Desired performance

The desired performance, as far as the durability of the component parts of

the devices is concerned, is not the same for all devices. A guideline,

considering life, period of replacement and cost effectiveness, needs to be

established depending on the design assumptions for a response-control

building.

3. Evaluation of fire-proofing or fire-resistance

The response-control device operates during an earthquake and reduces the

response of the building. It is thus an important device in terms of structural

safety. Many existing response-control devices use inflammable materials

such as laminated rubber supports. Presently, studies on their performance

during a fire or thereafter are not enough. It is therefore necessary to study

the performance of various response-control devices during a fire or

thereafter.

At present, we have no guidelines for the necessary performance level nor any evaluation methods to appraise the fire-resistance or fire-proofing of the

response-control device. These must be established as soon as possible. The

evaluation method has to consider the fire resistancy of the device itself

during a fire or thereafter, the structural role played by the device, the level of

fire hazard of the building occupancy, the position where the device is installed, etc. For example, the required fire-resistance or fire-proofing of the

device will vary depending on whether the device is installed at the

foundation where little temperature rise is envisaged due to fire, or it is installed in a place where the fire hazard level is very high. Similarly, the

required fire-resistance or fire-proofing will vary if the device is subjected to constant vertical load such as that due to various supports. We must

establish a method for evaluating fire-proofing and fire-resistance of the

device which is compatible with the design for fire-proof or fire-resistant

buildings after considering the above factors.

Construction

us discuss the base isolation type vibration-isolator construction, most frequently used

ay.

1. Safety during construction

There are two types of construction methods. In the first, a superstructure

and a foundation structure are made separately and laminated rubber is placed between the foundation and the superstructure. In another method,

after the foundation is made, the laminated rubber is placed above it and then

the rest of the structure is constructed.

-77-
In the former method, metal spacers are inserted temporarily in place of

laminated rubber bearings during construction. After the completion of the

structure, it is jacked up and the spacers are removed and are replaced with

laminated rubber. The technological problem with this method is how to ensure the safety of the superstructure under construction. Presently, this

method has never been used in the construction of very large buildings, but

this problem will be great if large buildings are planned in this way. A study

is also needed on the stresses that develop in foundation beams, etc. when the

structure is jacked up from the foundation. When the jacking up operation is in progress, the laminated rubber is subjected to tension or compression.

Effects of these stresses, however, have never posed serious problems, but

some study is needed depending on the size of building (area and height) and

the vertical stiffness of the laminated rubber.

Even in the latter method where laminated rubber is placed after completion

of the foundation construction, the vertical stiffness of the laminated rubber

may pose a problem. If the rubber is soft vertically, we need to determine the

method of loading or the order in which the columns are to be cast so that

columns do not sink in a nonuniform manner (differential settlement).

Another technological problem associated with these two methods is the

development of machinery (tools for jacking up, measuring equipment,

machinery for handling laminated rubber bearings) required for such

construction.

2. Quality control

Three aspects of quality control must be considered during installation of base

isolation devices (rubber laminates, dampers): (a) inspection before

installation; (b) inspection during installation; and (c) inspection after

completion of the building.

Standardization and specifications for the items to be inspected at each stage are essential for future technological development.

Maintenance

1. Maintenance methods

Once the building is in use, the device itself must be checked to make sure

that under no circumstances is its functioning affected. Presently, various

management systems, inspection methods, criteria for repair and

replacement, and processing methods have been proposed to ensure normal

operation of the device. However, the problems remain including the terms

of agreement among the buUding user and the structural designer or terms of

agreement between the manufacturer of the device and the construction

company. Some legal measures, including the warranty period, must be

established relating to the maintenance of laminated rubber bearings.

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Particularly, in the case of rubber laminates, a specialist must participate in

the inspection or repair of the devices. Training of those specialists and

development of techniques related to maintenance are requested for this

purpose.

2. Safety checks

Presently, routine checking is the responsibility of the building user. The user must fully understand the points to be inspected for the proper functioning of

the base isolation devices or peripheral equipment, their performance and

properties. Such knowledge must be shared with the general public. The

addresses of persons to contact in case of emergency and the address of the

manufacturer should be clearly indicated. It is also necessary to form a service

agency which can undertake repairs if faults are detected during routine

inspection. Such an agency could be the agency for maintenance, inspection

and repairs of base isolation buildings.

Checks on the condition of base isolation devices after severe earthquakes are

also necessary. Criteria for such temporary inspection must be developed and

decision should be taken on whether to make them obligatory. On the other

hand, the development of devices which will not require such detailed

inspection is eagerly awaited.

4.2. Suggestions for the Future

To ensure the smooth development of response-control structures in the future, the

construction industry should note the following points:

1. Encouragement for technical development

It is not sufficient to establish the specifications for response-control structure:

it is also necessary to encourage the new technological development required

for this purpose. To do so, positive efforts must be made to implement the

suggestions in Section 4.1. The development of devices related to the

response-control/base isolation structure, however, should be entrusted to private industries.

2. Simplification of permission for buildings

Although it is necessary to carry out safety checks thoroughly, there must be

no inordinate delay in conducting these checks or the procedures involved, as

this would hamper technical development. To popularize the use of the

response-control structure, it may be necessary to develop standard

specifications for the commonly used devices and also to establish a system to authorize the performance of these devices.

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3. Options for designers and developers

Instead of laying a fixed standard, a guideline may be laid so that designers

and developers can exercise professional options.

4. Encouragement of high-level technology

Buildings constructed with high-level technology should be carefully

evaluated and reviewed so that active technical development is encouraged.

5. Exchange and collection of technical information

The exchange, collection and active application of technical information

should be promoted so that technical development proceeds in the building

industry.

Efforts should be made to compile experimental data and measurements in

the case of actual buildings, and feedback should be promoted for further

technical development.

6. Preparing an optimum evaluation method for effectiveness of responsecontrol structures

The effect of reducing the response of the response-control structure to external turbulence should be evaluated from various angles so that the

effectiveness of such structures is correctly evaluated by the general public

and the social atmosphere is created for complete development of responsecontrol structures.

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CHAPTER 5

EVALUATION OF EFFECTIVENESS OF RESPONSE-CONTROL

AND BASE ISOLATION TECHNIQUES

From among the many types of response-control structures available we shall restrict our

discussion in this chapter to Menshin technique using base isolation.

In Section 5.1, "Points for Effectiveness Evaluation," the following five points are considered for evaluation:

1. safety; '

2. living comforts;

3. performance;

4. economy; and

5. design freedom.

For the purpose of building administration these items should be evaluated from the two

points of view.

The first is evaluation from the legal point of view. In any case, when a comparatively new

and still developing technique like base isolation structure, is used for buildings before

obtaining proof of safety, some special considerations should be taken in order to prevent

accidents or damage. This is an important factor in the safety evaluation mentioned above.

This point is considered by the Ministry of Construction while approving buildings based

on the technology according to the regulations. However, this evaluation of safety as specified in the building regulations is of the lowest level. In addition to this lowest level of

safety evaluation, there are other factors to be considered such as opinions of designer,

building owner, and general public.

The other aspect is related to the promotion of healthy development of this technique by

suggesting the objective evaluation method for the effect of the response reduction.

Evaluation points (2) - (5) correspond to this.

Based on these considerations. Section 5.1 deals with these five items and major points to be

discussed.

Among the above aspects of safety evaluation, the items and methods used for evaluation

by the Ministry of Construction for statutory approval of buildings, particularly those

directly related to the safety of the structure during an earthquake, are discussed in Section

5.2.

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Many of the above points can be used for response-control and base isolation (Menshin)

techniques in addition to the base-isolation technique.

While preparing guidelines for evaluation and approval of these structures in the future,

the suggestions contained in Section 5.2 will serve as a valuable reference.

5.1. Points for Effectiveness Evaluation

The performance of the base isolation technique can be classified in three ways as shown in

Fig. 5.1.

The most fundamental aspect is "dynamic properties." For example, we can include such

basic dynamic properties as reduction in the response acceleration, relative story

displacement and stress in each member or increase in relative displacement between the

earth's crust and the foundation. The effects that can be observed according to dynamic

properties include prevention of sliding or rolling of things stored in the building,

prevention of damage to the non-structural members, reduction in the cross sectional area

of structure members and reduction of vibrations felt by inhabitants. On the other hand,

the need for external piping or the need for countermeasures to safeguard deformation in

piping are among the adverse effects of using such means.

These effects in total will result in improving the quality of the building in terms of safety,

living comforts, performance, and economy.
Dynamic properties Reduction in

response acceleration

response relative displacement

response material stress

Increase in relative displacement

-between the foundation and the earth's

crust

Effect Prevention of sliding or rolling of

objects in a building

-Prevention of damage to non-structural

members

-Reduction in the cross-sectional area of

structural members

-Reduction in vibrations felt by

inhabitants

-Measures to counter the deformation of

piping and external wiring

Add advantage in - —Safety —Living comforts

Performance

1—Economy

Fig. 5.1. Points for evaluation of effectiveness.

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In evaluating the effectiveness of the base isolation structure advantages and disadvantages

are revealed, and all these aspects must be evaluated to determine the actual added value of a base isolation structure. In practice, however, the points to be evaluated may vary

according to the factors contributing to each technology; naturally, the weight attached to each factor will also vary.

Evaluation in terms of the public safety should be based on the safety factor as specified in

the regulations mentioned at the beginning of this chapter and other aspects related to technological development.

Below we discuss evaluation of usefulness on the basis of the added value of buildings with

base isolation structure in comparison with buildings without base isolation structures.

1. Safety

Safety during an earthquake includes the safety of the structure and the safety of

objects other than the structures.

Among these, if safety of the structure is hampered for any reason, the threat of

hazard to human life is very great and damage to the structure could cause

dislocation in other public services. Accordingly, investigations by state agencies

must ascertain that safety above a certain norm has been maintained based on the

Building Standard Law.

There is no theoretical contradiction between the base isolation structure and

conventional earthquake-resistant structures. Both have common aims, but the

standard of achieving them are different. Compared to conventional earthquakeresistant structures, experiences with base isolation structures during earthquakes

are few. It is therefore not possible to apply the same methods of evaluation of

safety standards as applied in conventional earthquake-resistant structures for

which we have copious results and experience.

In the base isolation structure, the load on the upper structure is reduced, and is concentrated on the base isolation device (mechanism). Therefore, the reliability

of the base isolation mechanism is important.

Ensuring the safety of items other than the structure includes checking whether

there is any damage to the non-structural elements, or whether there is any

sliding, rolling or falling of the equipment or the contents of the building. The

non-structural elements include stores of hazardous materials, flammable

materials, transport equipment or external walls or the signboards on these walls.

Any damage to these items may endanger human life or cause other public

hazards; they cannot be ignored during a safety evaluation.

In either case, for safety evaluation, it is necessary to accurately evaluate the

dynamic performance of the base isolation structure under the conditions for

which it is intended.

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2. Living Comforts

The improvement in the living comforts of the building with the use of a base

isolation device is due to reduction in response acceleration since the vibration

characteristics of the base isolation structure have a long period of oscillation.

Even vibrations caused by factors other than earthquakes (traffic, construction,

operating machinery) are reduced as a result of the base isolation device.

However, swaying due to such external forces as winds with considerably longer

periods of vibration may increase. Even during an earthquake, if the vibrations

continue for long periods the sway may increase and residents may suffer from

symptoms like sea sickness.

Body sensitivity to vibrations can be ignored to a limit. Quantitative evaluation

of this limit is possible for vibrations of comparatively short periods. However,

since the data for long-period vibrations is not adequate, such quantitative

evaluation cannot be done.

The importance attached to living comforts, as well as the structural aspects, have

emanated from the current trend in building technology toward improvement in

the quality of environment. Evaluation of living comforts is done by the owner,

occupier, or designer and statutory provisions need not be incorporated unless

social problems arise.

It is in the interest of the owner, occupier and designer to establish some rational

and objective method for such evaluation.

3. Performance

With the inclusion of the base isolation structure and the resultant reduced

response acceleration, sliding or rolling of equipment or their faulty operation is avoided; the buildings for emergency operation, production management, or information processing have the advantage of keeping their functions.

Buildings with conventional antiseismic structures also possess these properties.

The criteria for deciding which method to choose vary with each case. It is difficult to determine a common manner in which to evaluate the effectiveness

of performance, and a method must be evolved which considers the type of

building and type of construction. In doing so the requirements from the

building and its construction can be specified for the desired performance against

vibrations and then accordingly a method of evaluation is established. This will

be very useful for proper development of the base isolation structure.

4. Economy

Table 5.1 shows the cost of the base isolation structure compared with the cost of

conventional earthquake-resistant structure in qualitative terms. The cost

comparison is made by dividing the cost into factors, namely, physical factors

such as increased variety of construction materials, and the process factors from

design to construction and subsequent maintenance.

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Since the seismic force and the relative story displacement of a building are reduced in a base isolation structure, the deadweight (mass) of the upper floors

decreases, and the installation methods for equipment and instruments becomes

simple. The cost due to physical factors is therefore less. On the other hand, the

cost increases due to using a base isolation device (e.g., double foundation), the

necessity of using flexible joints in piping to overcome relative displacement

between the ground and the building, increased length of piping and others.

The main process factor is concerned with manpower. During the design process,

the cost increases if dynamic analysis is considered necessary. During

construction, the cost generally increases since the quantity of work, the period of

construction and materials to be managed all increase. The maintenance must

also be carried out with more precision than in case of conventional buildings,

and hence the cost increases.

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Table 5.1. Cost comparison of base isolation and conventional structures

Item Cost Reasons

1 2 3

I. Physical factors

a) Structural part

Superstructure Less Mass is reduced since seismic force is reduced

Foundation or base isolation

mechanism

More Double foundation and addition of

mechamism

Base isolation mechanism More Absent in non-base isolation building

b) Non-structural part

Finishing material, equipment,

instrument piping

Less Fitting procedure is simplified since

aceleration and interfloor

displacement are reduced and mass is also reduced

External piping or wiring More Counter measure for relative

displacement such as flexible joint

and longer route, etc., are required

n. Process factors

Design More Dynamic analysis

Less Only if standardization is possible

Construction More Volume of work, duration of work,

and items of quality control increase

Maintenance More Point check, protection is required

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To correctly estimate costs, all factors should be considered with proper weight.

In many cases the cost of the base isolation structure is higher than that of

conventional structure.

However, the costs vary according to the type of building or the prevalent

economic conditions. One should also consider the residential comforts,

performance and other activities. It is not possible to evaluate the structure

undimensionally.

5.2. Evaluation of Safety

The various viewpoints related to the evaluation of the base isolation structure are mentioned in Section 5.1. Here, we shall discuss the safety parameters, particularly those

considered by the Ministry of Construction or the Building Center of Japan for building

approval.

The safety of the base isolation structure is mainly determined from the dynamic

performance and can be broadly divided in two types: normal behavior and the behavior

during earthquake. Such behavior depends on the structural performance of the base

isolation device, design specification, design method, reliability of the construction and

maintenance.

We shaU discuss each point in detail.

1. Design Criteria

During the design of the base isolation structure, first the design load has to be set and design criteria for that load have to be determined after considering the

application and importance of the building.

1. Types of loads and external forces

The types of loads and external forces may be the same as those for

conventional antiseismic structure. These include dead load, live load, snow

load, wind load, seismic force, soil pressure, water pressure, and other loads

or external forces.

The values of these loads and external forces, specified in Building Standard

Law or structural calculation standards of Architectural Institute of Japan, are based on past experience and results obtained from conventional non-base

isolation structures and are considered more as promises made by designer

based on engineering conclusions. Thus, during the design of base isolation

structures, while evaluating load and external forces, it may be necessary to reconsider some actual phenomena, such as strong winds or earthquakes.

Among these actual phenomena, the seismic force is determined as a result of

the seismic response of the building. The seismic force for a base isolation

-88-
building, should be evaluated carefully, taking its longer fundamental period

and nonlinearity into account.

2. Uses and importance of the building

Understandably, the design targets are set according to the uses and

importance of the building. For a base isolation structure, as a basic rule of

design, the condition of the seismic response is studied in detail through

dynamic analysis, and the results are used in the design.

In this case, it is possible to set the criteria related to structural safety or those

related to the performance of the building in more detail than in the case of a conventional building.

Clearly, with this assumption, the seismic motion which is likely to be

incident at the building needs to be evaluated properly.

Presently, since analysis of performance of actual available construction is limited even during the design of an ordinary office building, the same level

of seismic motion is assumed as for a multistory building. This practice

should be reviewed considering the current norms and design practices for

earthquake-resistant buildings of the same size and uses.

3. Response criteria

The response criteria of buildings to various loads and external forces are as follows:

1) In the case of vertical loads such as dead loads, live loads or snow loads, the

building should not sink non-uniformly nor should there be excessive sinking.

This is not limited oiUy to base isolation structures. For base isolation structures

particularly, the foundation structure plays an important role. If it does not

perform in the specified manner, then the base isolation structure will not be

workable; it is therefore necessary for design against vertical loads to be more

precise than in conventional buildings.

2) In the case of wind loads, the stresses in the structure, developed in response

to the wind loads, should be kept within the elastic limits which conform to the

specification in Building Standard Law. It may be necessary to study the

vibrations due to wind load in terms of living comforts. As far as a general base

isolation structure is concerned, this need not be considered as a criterion for

safety.

3) The behavior of buildings in response to an earthquake may be considered

separately from conventional buildings and multistoried buildings taller than

60 m.

According to the code regulation, there are two types of considerations for

ordinary buildings, as follows:

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i) During the course of its life, a building may be subjected a few times to earthquakes of moderate strength (of the order of 80-100 gal on the ground

surface). On those occasions, the performance of buildings should be

problem free. Damage may be minor and restored easily.

ii) Very strong earthquakes (of the order of 300-400 gal on the ground

surface), which are quite rare, may never strike a building during its life. However, even if the structure is severely damaged, it should not

collapse. Nonetheless, this is not sufficient security for important

buildings such as emergency operation center, and other measures are

carried out. For such buildings, the performance has to be maintained even under severe earthquake conditions.

For multistoried buildings taller than 60 m, the Technical Appraisal Committee

for multistoried structures in the Building Center of Japan has listed criteria

under the title "Seismic Motion for the Dynamic Analysis of Multistoried

Buildings" and published them in The Building Letter, Tune, 1989.

i) The building should withstand without damage against an earthquake

ground motion which is likely to strike the site of the building more than once during its life. The main buUding structure should exhibit response

mostly in the elastic region. Seismic motion of this intensity is called

seismic motion of level 1.

ii) The building should withstand, without any threat to human life such as collapse of main structures or exterior walls, against the earthquake which

is considered to be the highest amongst the seismic motion recorded in

the building site in the past or which is likely to strike the area in future.

Seismic motion of this intensity is called seismic motion of level 2.

For buildings constructed on the gravelly soil of Tokyo, the maximum velocity of

the seismic wave, used for dynamic analysis of the upper structure with a basement and foundation, is as follows:

Seismic motion of level 1 ... more than 25 cm/sec

Seismic motion of level 2 ... more than 50 cm/sec.

Even in the case of base isolation structures, most of the safety norms for

earthquakes are common to those in conventional buildings. The period of

vibrations is longer in the base isolation structures and similar to that for

multistoried buildings. The maximum value of the seismic wave for dynamic

analysis is specified in terms of the maximum velocity. The intensity of an

earthquake is designated as level 1 (25 cm/sec) or level 2 (50 cm/sec), similar to that for multistoried buildings.

As mentioned before, there is some room for review of the design criteria of

earthquake-resistant buildings and of the uses and importance of buildings.

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Table 5.2 shows the proposed design criteria of base isolation buildings with this

understanding.

Table 5.2. Seismic response criteria of base isolation structures

Level External force level Building Base isolation devices

I Weak earthquake, about 30-50 gal Elastic Elastic

n Moderate earthquake about

80-100 gal

Below permissible

stress

Elasto-plastic below permissible deformation**

m Severe earthquake once in 50

years or corresponding to 25 kine

Below yield

strength

Elasto-plastic below critical

deformation**

IV Very severe earthquake once in

100 years or corresponding to 50

kine

Below permissible

ductility ^

Elasto-plastic below critical

deformation**

V Mega earthquake* Without collapse Collapse permitted

*Mega earthquake is the maximum earthquake likely to strike the building site.

**Laid according to the properties of the Menshin mechanism. Permissible

deformation < Critical deformation.

2. Seismic Motion for Design :,

The following points must be considered while prescribing the seismic motion for design

purposes. .

1. Maximum amplitude

The maximum amplitude of seismic motion to be used for design is decided

in accordance with the design criteria. Since, the Menshin structure with

base-isolation usually has long period vibrations, the maximum amplitude

should be determined in terms of the maximum velocity. However, while

laying the maximum amplitude of a small to medium earthquake, it is more

meaningful to consider the acceleration than the velocity. If we consider

earthquake resistance of conventional building structures, the criteria may be

laid according to the level of the earthquake as shown in Table 5.2. There is another method in which both velocity and acceleration values are

considered.

The conventional method in deciding the maximum amplitude of vibrations

is quite simple. Here, the standard value is first determined and then

multiplied by the zonal coefficient according to the regional activity

(probability and intensity) of the earthquake. If we consider that in base

isolation structures, componental response of longer periods may be

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predominant, and that the investigations about the earth's crust and response

analysis may be conducted in detail, it is probably more suitable to calculate

the amplitude after considering the level of seismic activity in and around

the building site or the dynamical properties of ground motion of that area. Waveform

In the case of buildings taller than 60 meters, three types of seismic

waveforms have been used for dynamic analysis of the building: the standard

seismic waveform, the seismic waveform representing the zonal properties,

and the seismic waveform incorporating the long-period component (after

Japan Building Center's article "Seismic Motion for the Dynamic Analysis of

Multistoried Buildings" published in The Building Letter, Tune, 1989).

A similar consideration is suitable for base isolation structures. Summarizing

the aspects from the viewpoint of the selecting the waveforms we find:

1) Typical waves in the past (standard seismic waveforms) such as:

El Centro 1940

Taftl952

Hachinohe 1968

2) Measured waveform near the construction site.

3) Simulated seismic waveform representing zonal properties, properties of

the earth's crust.

4) Recorded waveforms incorporating the long-period component (or

alternative seismic waveform incorporating the long-period component)

such as:

Hachinohe 1968

Akita 1983.

In addition, we also have records of Mexico earthquake (1985) which has a seismic wave with prevalence of long-period component. However, its properties are exceptional and such an earthquake is not expected to occur even in Japan. There are doubts, therefore, about whether it should be used

in Japan for design purposes. While studying local safety, the use of the

resonant wave is suggested. This needs to be further studied.

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3. Multi-dimensional inputs

The principal axis (direction) of vibration of a base isolation structure is not as

clear as in an ordinary building. It may, therefore, be useful to study safety

assuming an incident input ground motion having components in both

directions of the horizontal plane.

It is assumed that there will be little effect due to vertical motion of the

ground but this may need to be considered.

For such multi-dimensional inputs, we can use recorded waveforms or simulated seismic waveforms, but at present we do not know what type of

possible waveforms is critical in the design of base isolation structures.

Future studies will be necessary about this problem.

3. Methods of Dynamic Analysis

The reliability of vibration analysis depends on

1) whether the factors governing actual response are made into an accurate

model or not, and

2) whether constants used in the model reflect the actual structure or not. We discuss these points here.

1. Dynamic-analysis model

The model used in dynamic analysis of the base isolation structure should

allow the motion of a building structure in at least one direction. Even then,

if the structure above is stiff, we can use a single degree of freedom model. If

it is not stiff, we cannot ignore the effect of higher mode of oscillation. Hence

it is better to use the multi-degree of freedom system model.

When the torsional oscillation is expected to occur or while studying the

response to multi-dimensional inputs, we must use the multi-degree of

freedom model considering these points.

It is generally assumed that the correlative dynamic action between the base

isolation building structure and the earth's crust is small, but sometimes we

may require a model which considers this interaction.

2. Restoring-force characteristics

The restoring-force characteristics of base isolation devices and building

structures should be made into an optimum model which reflects the real

situation.

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For example, there is a limit up to which the deflection in rubber material can be considered as linear and hence analysis in the region beyond this limit has

to be conducted with a nonlinear model. This is not limited only to the base

isolation structure. Since there is some sort of fluctuation in the physical

value of restoring-force characteristics, their effect on the response calculation

should be studied.

3. Damping constant

The damping constant used for vibration analysis of base isolation structures

may be determined separately for each structural element and can be laid

differently for the base isolation device and the building structure.

Previously, the damping constant was determined in gross for the

fundamental mode of oscillation. In the case of base isolation structure, we

expect no interaction between the building and the ground, and a special

damping element is used for the base isolation device. Therefore, in this case we cannot use the conventional approach. When the upper structure is considered stiff, the damping properties of the entire structure are in line

with those of the base isolation device and the conventional approach can be

applied. According to recent studies, the value of damping constant or

reinforced concrete buildings having cracks in structural elements is less than

3% excluding the damping properties of base isolation materials such as rubber, which can be ascertained experimentally.

Basic concept of structured design

1. Design process

Even for base isolation structures, the design for the vertical load is made

first. The cross section of the upper structure in the base isolation building is smaller than that in a non-base isolation structure. There are no other

differences in the design of structural members for vertical load. The base

isolation supports act as supports for the upper part of the building; hence,

care is needed to ensure that there is no nonuniform or excessive sinking of

columns due to load.

The design for the horizontal force considers mainly the seismic force.

Evaluation of the seismic force should be based on the consideration on the

longer fundamental period and nonlinear properties of base isolation

structure. According to the present seismic design code, the seismic shear

coefficient for each floor should be determined on the basis of building

height. This value can be decreased to 75% based on a proper analysis. This

provision is used in the base isolation buildings approved so far by the

Ministry of Construction where the shear coefficient of the first story is above

0.15.

It may be possible to further reduce the seismic force according to the results

of vibration analysis but considering the uncertainty of seismic motion, the

extent of reduction has been restricted in previous approvals.

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The results of vibration analysis may be used for the distribution of the story

shear coefficient in the vertical direction (Ai) .

2. Confinnation of ultimate condition

Even w^hen safety at the design earthquake is ascertained, we cannot

guarantee the result if an earthquake of higher intensity occurs. This is related to the intensity and properties of seismic ground motion assumed in

the design. In the base isolation structure, it is necessary to estimate the

ultimate condition and leave some safety margin for that design level.

Sometimes the use of fail-safe mechanism is proposed to avoid the collapse of

the building under ultimate condition. When such fail-safe mechanism is used, the mechanism must demonstrate its expected effect.

Studies must determine whether fail-safe mechanisms are really needed. In

the case of a jet passenger aircraft, the inertial guidance system and hydraulic

system for stability control are designed to include three independent

subsystems in order to prepare for the misoperation or the break-down.

However, a situation in which all of them fail is not considered.

3. Design of foundation

For the base isolation device to demonstrate its working, the foundation

structure has to be perfect. It is so designed that there is no nonuniform or excess sinking of columns and that the foundation can withstand horizontal

force.

The horizontal seismic force for the design of foundation structures is the

sum of the shear force of the upper structure as determined by vibration

analysis and the inertia force on foundation structure itself. (However, when

the shear resistance of the upper structure is designed stronger in spite of the

results of analysis, that should be used in place of the shear force of the upper

structure.)

4. Design of secondary elements and equipment.

The secondary elements and equipment are so designed that they are safe at the maximum response and relative story displacement obtained through

vibration analysis. The response acceleration and the relative story

displacement of an upper structure decreases greatly compared to the nonbase isolation structure. This facilitates the design process.

On the other hand, since the relative displacement between the ground or neighboring buildings is greater than in ordinary buildings, arrangements

must be made for piping, deformation of wiring and so on. Particularly for

gas pipes which have a high hazard level, an alarm system must be provided.

Proper safety arrangements must be made for fire hydrant pipes, which have

to operate normally under the emergency.

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Performance of the base isolation device

A base isolation device is the principal component of a base isolation structure.

Accordingly, its dynamic properties, endurance properties and fire resistance

should be ascertained experimentally.

The device may be promoted by issuing a certificate that the specified checks have

been carried out or we can ensure the performance by setting adequate standard.

1. Dynamic performance

It is necessary to ensure the following for the dynamic performance of a base

isolation device:

1) Load-deformation relationship .

This may vary according to operating conditions, but generally it should

express the relationship between different types of forces such as compression, tension and shear with stiffness, resistance, deformability,

creep characteristics and energy absorption properties.

2) Damping properties

3) Dependence of dynamic properties on temperature, deflection, frequency.

2. Durability

This is closely related to maintenance. Change in the properties of materials

due to aging so that the desired performance cannot be obtained must be

arrested and corrected. The effects of weather, ozone, heat, cold, chemicals,

oil, wear on the performance should be ascertained experimentally

simulating operating conditions.

It is useful to study the performance of this device even for uses other than in

base isolation structures.

3. Fire resistance , ,

In case of base-isolation method, the base isolation element is often placed

between the double layered foundations. Hence, fire resistance is not so

essential but still should be ascertained.

The space between double foundation could be used as a part of the building

space but, after considering the level of fire hazard in that space or the fire

hazard of the entire structure and the fire hazard due to earthquakes, the fire

resistance required for the base isolation device should be evaluated. For

diverse development of base isolation structures, these studies should be

conducted immediately.

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6. Construction

The most important aspect of construction of the base isolation buildings is the

management to achieve the desired performance. Because the fundamental

period and damping properties of the base isolation system should be realized

more deliberately than in the case of conventional non-base isolation buildings,

the importance of quality management is great. It may also be necessary to study

the safety of the structure during construction.

The base isolation device may be considered an industrial product and the

materials management may be carried out on the basis of quality, appearance,

dimensions, and manufacturing method.

Quality control includes checking the standard developed for quality assurance during manufacture and some intermediate inspection, if required, as well as obligatory inspection on receipt of goods. Inward inspection includes checking

the quantity, appearance, dimensions and results of materials inspection. The

rejected goods are sent for repair or modification.

Quality control during construction aims at preventing damage and ensuring

accuracy of fittings. This is checked at the time of receipt and after completion of

the building.

The materials management methods may differ depending on whether the base

isolation device is fitted at an earlier or later state in construction.

7. Maintenance

If after completion of the building, a fault develops in the base isolation device,

which is the heart of the entire base isolation structure, the device will be of no

use during earthquake. Continuous maintenance of these devices is therefore

necessary to avoid such situations.

For proper maintenance, it is necessary to clearly specify the maintenance system,

the periods of checking, the items to be checked, and the methods and procedures

for emergency conditions.

Maintenance of structural performance is also necessary for conventional non- base isolation buildings, but this has been done successfully under the

responsibility of the owner. On the other hand, in the case of base isolation

structures, the behavior of a building during an earthquake is controlled by the

mechanical part which is the base isolation device and, hence, maintenance

should also include regular checks of the device. This is similar to the

maintenance of elevators. Many points have to be studied while evaluating the

safety of a building from the maintenance point of view.

-97-
CHAPTER 6

SUMMARY

During the first stage of this study, it was decided to explore the current status of the

response-control structures and the possibility of using them. The topics of study for the

methods of evaluation of response-control structures, particularly the base isolation

structures, were broadly summarized. We find that more attention should now be paid to four points:

1. preparation of guidelines for evaluation and approval of base isolation

structures;

2. preparation of guidelines related to the performance of base isolation devices;

3. facilities to encourage exchange, collection and dissemination of technical

information on the response-control structure; and

4. study of methods of evaluation of performance of response-control

structures.

Below, we offer some comments on these points.

1. Preparation of guidelines for evaluation and approval of base isolation

structures

All considerations in the evaluation of base isolation structure must be made

in terms of safety point of view. Studies on the items discussed in Chapter 5

should therefore be carried out immediately.

2. Preparation of guidelines related to the performance of base isolation devices

The development of various base isolation devices is generally done by

private industries. Clarification of the performance to be guaranteed, the

necessary specifications and standardization of devices can be done in the

second stage of this study. The information about the devices given Section

4.1 of this report v/ill be useful here.

3. Facilities to encourage smooth exchange, compilation and dissemination of

technical information on response-control structure

-98-
Section 4.2 deals with the development of new techniques in responsecontrol structures and their improvements. Due protection must be provided

for various claims about innovations (patents) and information related to safety has to be circulated among developers, users and government officers.

EHiring the second stage of our study, we should consider developing an agency for this purpose. The present arrangement in the aircraft industry, to ensure the exchange of information among manufacturers of aircraft, airlines

companies and governments, may be used for guidance.

4. Study of methods of evaluation of performance of response-control structures

Response-control structures reduce the response of a building to external

turbulence and improve its performance. Hence, to promote the

development of response-control structures, we should establish some fair

and objective method of evaluation of the extent of reduction in the response

of any building to external turbulence using these response-control structures.

-99-
r

APPENDIX 1

VARIABILITY OF THE PERFORMANCE OF

RESPONSE-CONTROL STRUCTURES

We shall not review here the reliability of response-control devices but the uncertainties or

variability of loads and structural properties assumed in the design of response-control

structures. The effect of the variability on the overall reliability of the system w^ill also be

considered.

It is quite clear that the vibration levels assumed in the design of response-control

structures, and the corresponding variability, varies depending on different sources of

vibrations. The variability of external turbulence levels assumed in the design, which is due to natural phenomena such as earthquakes or stormy winds, is in many cases caused by

differences in modeling those phenomena.

Seismic ground motions assumed in the design are calculated by analyzing historical data,

simulated seismic activity models, etc., where the upper limit of earthquake magnitude is supposed to exist or not. The variability of those seismic ground motions assumed varies

depending on the method of analysis or modeling of earthquake phenomena. The

coefficient of variation reported is 140% (Ref. 1), irrespective of the return period, which is a considerably larger value among those values reported, or 100% for the return period of 100

years and 50 to 70% for the return period of 50 years (Ref. 2), which are smaller values

compared with others. The uncertainty in evaluating the ground motion magnification in

subsoil layers can be expressed by the coefficient of variation of acceleration response

spectrum on ground surface except in case of extremely complex subsoil conditions.

According to Ref. 3 values of the coefficient are 20 to 30%. As far as the subsoil properties are estimated adequately, the coefficient of variation of incident seismic ground motions

assumed in the design can be considered as large as those stated above.

While studying variations in wind load evaluation, Ref. 4 has cited the variation of gust

response of high-rise buildings. If we assume that shape factors and surface roughness of

the building site are evaluated with some accuracy, we can consider that the variation of

wind load is caused mainly by the suitableness of a probabilistic model of strong winds.

According to Ref. 4, coefficient of variation in wind load evaluation is 50% and 40% for

return period of 100 and 50 years, respectively (Ref. 5).

For mechanical vibrations or those due to traffic, if the properties of the vibration source are determined accurately, the variation should be much less than for an earthquake or strong

winds.

-100-
Evaluation of variations in input forces is quite useful for setting the vibration limits over which the damping effect can be expected in a linear as v^ell as non-linear system. It is also

important to determine the level of reliability of control when vibrations are within the

design specifications.

In evaluating the effect of the response-control structure, it is also important to accurately

determine the fundamental periods of vibration and the damping of the proposed building.

The accuracy of these two factors causes some effects on the performance of responsecontrol devices more or less depending on the type of those devices. Some devices may be

easily adjusted for their properties, while some may not. Below we mention the general

accuracy of performance prediction.

The fundamental periods of vibration may now be determined quite accurately using the

analytical approach. However, they are related to the evaluation of the effect of secondary

elements and earth's crust. In many cases, analyses of fundamental periods of vibration do

not include this effect and, therefore, the accuracy may be in a similar level as that of a simple approximate calculation based on the number of stories or building height. Ref. 6

has pointed out that the detailed method of predicting fundamental periods of buildings

may sometimes include an error up to 50%. If the vibration records are available for a

similar building, a certain level of accuracy can be maintained by making proper corrections.

Even then, we must remember that the fundamental periods of oscillation will vary

according to vibration levels or the history of previous seismic shocks.

It is not easy to determine the damping constant of a structure by the analytical approach. It is generally set between 2 and 5% except when damping is evaluated on the basis of

interaction between the earth's crust and the structure. A method to estimate the damping

constant based on the fundamental periods and amplitude of target vibrations has also been

proposed (Ref. 7), but even there the error cannot be controlled within 50%. Accuracy in

estimating the damping constant can be improved if the results of the seismic

measurements for similar structures are available, as in the case of fundamental periods of

vibration. For the microtremor level, Ref. 7 reports that, with enough accuracy, damping

constant in % is equal to the value of fundamental period of ground oscillation in Hz. The

fundamental frequency and damping constant of microtremor can be determined

comparatively easily by actual measurements. However, an accurate estimate is not always

possible during the design period and hence, evaluation of the effect of the damper device,

assuming some variation in the system properties, is necessary.

-101-
B. Ellingwood, et al. 1980. Development of a probability-based load criterion for

American National Standard A-58. NBS Special Publication 577, pp. 121-126.

Dan, Kazuo and Jun Kanda. 1986. Analysis of earthquake hazard level using

extreme value distribution with upper and lower limiting values. Nippon

Kenchiku Gakkai Ronbun Hokoku-shu, No. 363, pp. 50-56.

Ota, Tokiharu and Haruhiko Ando. 1977. Average properties of seismic motion

according to different types of earth's crust. Nippon Kenchiku Gakkai Dai Go

kai Chiban Shindo Symposium, pp. 27-34

Kanda, Jun. 1982. Probability-based evaluation of v^ind load considering dynamic

response. Dai Nana kai Kazekogaku Symposium, pp. 179-186.

Nippon Kenchiku Gakkai Kokozo Bunkakai LRFD Shoiinkai (Subcommittee on

LRFD under the committee for Steel Structures in Architectural Institute of

Japan). Method of load-resistance-factor design in steel structures, pp. 68-89.

B.R. Ellis. 1980. An assessment of the accuracy of predicting the fundamental

natural frequencies of buildings and the implications concerning the dynamic

analysis of structures. Proc. I.C.E., Part 2, Vol. 69, pp. 763-776.

A.R. Jeary. 1986. Damping in tall buildings—a mechanism and a predictor.

Earthq. Engg. Str. Dyn., Vol. 14, pp. 733-750.

-102-
APPENDIX 2

EXAMPLES OF RESPONSE CONTROL AGAINST WIND

Table 1. Mechanical means for suppressing wind-induced vibration of structures

Source: Nippon Kazekogakkai-shi (Journal of Japan Wind Engineering Association), No.

20, June 1984

Countermeasures for suppressing wind-induced vibrations from structural dynamic

viewpoint by Matsuo Tsuji

Method of P Applications and wind- Highlights of Occurrence Measures W Remarks,

response r induced vibrations methods, devices and of wind- taken i other

control e considered or observed effects induced n examples

c vibration d

e t d u

e nt n A B C D n e

t e s

1 t

1 2 3 4 5 6 7 8 9 10 A. Increase 0

stiffness

Al: Mukojima Bridge (span The ends of tension 0 0 0 Damaged

Mutual 118m Langer girder members were during

inter- bridge completed in reinforced (1970). Typhoon

connection 1968) tension members Longer members were No. 10 in between of 17m long H-section tied with each other 1970

members) (170 X 368) was

subjected to vortex- induced vibrations and

it became unstable at a wind velocity of 25-30

m/sec, leaving some

fatigue damage at ends

with horizontal wire

ropes at height of 7.9m

0 Burton Bridge (arch

type) 10-22m long Hsection (221 x 455)

suspenders having

holes in web to reduce

vortex-induced

vibrations, were

subjected to vortex- induced vibrations

under construction

when wind speed

exceeds 9 m/sec

Horizontal strut of

channel-shaped steel was fitted at a height

of 5.9m. 19mm dia

wire rope fitted

horizontally at the

height of 6.7m and

18.6m. Another 19mm

dia wire rope fitted diagonally at height of 13.4m.

0 0 0 0

-103-
1 2 3 4 5 6 7 8 9 10

0 Rokkaku Bridge

(double deck truss cable-stayed bridge

90+220+90m). Stay

cables at 5th level (PWS

85 dia) were subjected to wind-induced

vibrations.

Cables were

interconnected with

wire ropes

0 0

0 Heavy water plant. Port Hawkesburry. 2 slender

cylindrical towers out of

6 (3m dia, 70 and 75m

height, gap 9m) vibrated

witn an ampiiiuae or u.o- 0.6m when wind speed is 11-25 m/sec

The tops of two

cylindrical towers are

tied with horizontal

plane truss

0 0 0 0 La Prade

Heavy

Water

Plant. Al- can

Alii TVl 1 ^ /\iu.inina Plant

0 Multi-conductor electric power line Flexible spacer

(damping action)

0 0 0

0 Onomichi Bridge

(Cable stay bridge 85 +

215 + 85m). Vibrations

due to aerodynamical

interaction observed on

ropes (54-70 dia) set in a

parallel way.

The number of

spacers are increased

0 0

A2: Increasing

stiffness of

members

0

0

Bronx-Whitestone

Bridge (suspension

bridge, central span

701m, 1939). Stiffening

girder made of plate

girders. Frequent

vibrations during strong

wird

Golden Gate Bridge

(suspension bridge,

central span 1280m,

1937). If the wind speed

at right angles to the

bridge axis exceeds 13

m/sec there is torsional

vibration. In December

1951 at wind speed of 3 m/sec there was a mixture of torsional and

flexural vibrations

Stiffening with

additional trusses

(center tie and tower

stay also present)

Since some damage was caused to

accessories, stiffening trusses were changed

into a closed cross

section

0

0

0

0

-104-
1 2 3 4 5 6 7 8 9 10 A3: Stay

cable

0 Deer Isle Bridge

(suspension bridge,

central span 329m,

1939). In December,

1942 at wind speed of 32

m/sec, the amplitude of

flexural vibrations was

3.8m

Cable stay were added 0 0 Thousand

Islands,

others

B. Mass

addition

Bl: Rubble,

sand filling

method

0 Zdakova Bridge (arch,

effective span 330m,

completed in 1967).

Steel pipe supports 4.1m

dia, t = 12 mm, 1 =

41.48m. Vortex-induced

vibrations at V = 6-13 m/sec, resonance at 8

m/sec with an

amplitude of 13cm

Rubble filled for 31m

length. Resonance 5 m/sec, amplitude

1/20, f = 1.6 -» 0.73 Hz

8= 0.0078 -> 0.0195

0 0 Tjorn

bridge

(Arch, 1960)

B2: Water

filled pipe

method

Suspension Bridge.

Counter-measure was applied against

fluttering (torsional)

during installation

works of stiffening

girder

By placing the water

filled tubes facing the wind upstream, the center of torsional

rigidity shifts toward

the direction of wind,

increasing V^r

0

C. Added

damping

(Type 1: Asynchro- nous type)

CI: Viscoelastic material0

0

World Trade Center

(New York, 110 story

building). Gust

response vibrations

Bybrua Bridge

(Norway). Vibrations of

stay cable

Visco-elastic material

is inserted at connections between

column faces and

lower chord members

of floor truss girders.

Dimensions of viscoelastic material are

101.6 (w) X 254 (l)x 1.27 mm (t)

Rubber tubes placed

at the lower end of

stay cables for

absorption of

vibrations

0 0

Pamphlet

of 3M Inc. Columbia

Center,

Seattle

-105-
1X 2 3 4 5 6 7 8 9 10 Gymnasium. Aluminum sheet roofing on

eaves was peeled off due to vibrations (0.8

mm thick)

Asphalt cover around

the roof up to 5m

width

0 0

C2: Hydraulic

damper

method

0 Brotonne Bridge

(France) Prestressed

concrete cable stay

bridge, central span

320m. The cables

showed primary,

secondary and third

mode of vibrations

when wind velocity in the direction of bridge

axis ± 30 degree was 15 m/sec. In primary

mode amplitude was

about ± 30 cm.

Suspension bridge,

others. Flexural

vibrations due to wind

Each cable was

connected to two

hydraulic dampers

placed in an inverted

V-shape at a height of about 2.5m above

bridge surface to suppress vertical and

horizontal vibrations

Hydraulic dampers

are introduced at each

cable end.

0

0

0 Completed

in 1977.

West Gate

bridge

New Tjorn

bridge

C3: Fluidtank type0 Tower type structures

like chimney

Elevated water tank

Oil tank having

number of horizontal

separation plates is placed at the top (of

tower) and viscous

damping is achieved

with oil motion

Number of baffle

plates (vertical) placed

in water tank

0

0

0

C4: Wire

rope

method

(Guy

cable)

0

suspension bridge,

central span 988 m,

1966). Stability against

wind improved with

stiffening girders

Rol"ffit* *4 atYi n cr offo^-f L/CLLCl UClllLL'Xllli CllcCl due to tensile

hysteresis of diagonal

guy cables

n iJKJOlyiJl UOf Humber

0 Vortex-shedding

excitation of a construction tower at the time of erection of Severn bridge. Bending

vibrations at about 9 m/sec, torsional

vibrations at about 27

m/sec during wind

tunnel experiment

35 X 2 wire rope were

stretched from top of tower to anchorage

thereby absorbing

energy

0 0 0 Bosporus

bridge set- back used

-106-
1 2 3 4 5 6 7 8 9 10 C5: 0 Steel chimney (welded). At the time of 0 0 Damper dia 5.m, height 90m. At reconstruction, spring

spring type wind speed of about 16 and damper were

(DS) m/sec, cracks and

buckling developed in steel plates due to vortex-shedding

excitation

connected in series to the lower end of cable which extended from

tower top downward

C6: Sliding 0 Forth Road Bridge (UK, Wire rope was pulled 0 0 Weight of block type suspension bridge. from top of tower and block 16 t. (SB)

0

central span 1006m,

completed in 1964).

Vortex shedding

excitation of

construction tower

during erection. The

swing of top of tower at a wind speed of about 9 m/sec was 2.3m

Friarton Bridge (UK, 114 + 1/4 + 114 + 66 m,

continuous box girder)

vortex-shedding

excitation while laying

the projected girders of

central span

connected to concrete block on an inclined

sliding platform. The

sliding friction of block

is used to get damping

effect.

Wire rope is pulled

down from the center

of girder joining both

ends and connected to 6 t block placed on an inclined sliding

platform

0 0

In'noshima

bridge, 3P

tower. Kan'mon

bridge, etc.

C7: 0 In'noshima Bridge Wire rope is pulled 0 0 DW type

Damper (suspension bridge. from the top of tower on an in- and weight central span 770m, in an inclined manner clined type (DW) completed in 1983).

Vortex-shedding

excitation of

construction tower (2P)

during erection.

Resonance wind

velocity 9-12 m/sec.

Expected amplitude of transverse vibration at that velocity is 0.8m

and connected to hydraulic damper

(having variable

damping coefficient)

and weight (5 1)

platform

0 O'naruto Bridge

(suspension bridge,

central span 876m).

Vortex-shedding

excitation of

construction tower

during erection.

Bending and torsional

vibrations assumed

Combination of two

such assemblies

mentioned above.

Damper stroke is reduced using

balance. 20 t weight x

2 nos.

0 0 0 Seto Ohashi

bridge,

Shimotsui

-107-
C8: Block

under

water type

(BW)

C9: Gyroscope type

CIO: Pendulum

impact

type

D. Added

Damping

(Type 2. Synchronous

type)

Nankai Bridge (central

span 404m, tower height

60m). Vortex-shedding

excitation of tower

during construction.

Resonance wind

velocity is about 11 m/sec. In the absence

of damping, the

vibration amplitude of

0.5m is observed

Speyer Bridge (West

Germany, cable stay

bridge. 275 + 61 + 61 +

59m). Vortex-shedding

excitation of girder

during construction.

Completed in 1975.

Suspension bridge.

Increase in critical wind

velocity for fluttering

while laying stiffener girder

Suspension bridge.

Increase in critical wind

velocity for torsional

flutter

Chimney etc. or tower

shaped structures

Wire rope is pulled

from the top in

inclined manner. From the center,

another rope is suspended in water

with concrete block

A steel frame was

suspended into water from the girder using

wire ropes during

occurrence of

vibrations

A plate is suspended

into water from the

girder

Gyromoment

proportional to the

torsion angular

velocity has damping

action and as a result,

critical wind velocity is increased

When the pendulum

suspended from the

top hits impact plate

during its oscillations,

energy is consumed

(absorbed)

10 Completed

in 1972.

Situation

where

additional

dampers

were

required

did not

arise

-108-
1 2 3 4 5 6 7 8 9 10 Dl:

Damper

for aerial

trans- mission

line

Low-speed wind

vibrations: at 0.5 - 7 m / sec vertical

vibrations of 3 - 150 Hz

are produced

Energy absorption as a

result of deformation

of twisted wires

0 0 Also used

for preventing the vibrations

insuspenders

of Severn

bridge or Hamber

bridge

Concentrated type0 General area Stock bridge damper,

materials of better

quality

Distri- buted type0 Special areas like river

valleys, capes, mountain

ridge line, icingexpected region, etc.

Bate damper, etc. Spliced wire type

D2: Cantilever type

0 Commodore Barry

bridge [cantilever

(Gerber) truss, central span 501m]. H-section

vertical member was damaged due to vibrations during

construction. Bending

and torsion vibration

developed along both

principal axes of the

cross section at a wind

speed of 17 - 25 m/sec

during wind tunnel

experiment

Transport pipe bridge,

vortex-shedding

excitation

Total 920 dynamic

absorbers were fitted to 258 members. Each

absorber was made by

fitting a weight to the

lower end of rubber

rod 10 cm square and

60 cm long (1976)

The shear

deformation of viscoelastic material

between the double

layered beams is used

0

1:

0

0

0 0 Bras D'or

bridge.

Antenna

array

-109-
1 2 3 4 5 6 7 8 9 10 D3:

Pendulum

type

0 Sydney Tower (tower

height about 250m,

completed in 1981). The

design criteria for gust

response is such that peak acceleration is within 0.02 g. Wind

response measured

during December 1980 - August 1982

One of the two sets of tuned-mass dampers

(TMD) was placed

above observatory for damping primary

mode of vibration,

where doughnutshaped water tank

(180 t) was used as a pendulum of 10m

length and 8 dampers

were connected to it tangentially. The

other set of TMD for damping secondary

mode of vibration was composed of a 40 t steel ring suspended

with 1.2m rod in the

intermediate ring and

seven dampers

0 0 0 Antenna

tower. Chimney

0 Meiko West Bridge

(cable stay bridge,

central span 405m,

tower height 122m).

Vortex-shedd ing

excitation of

f^rwi cfn ir'fi on foTA/t^r during construction (V =

13 m/sec, anticipated

vibration amplitude

about Im). In absence

of damper 5 = 0.0078

Shear deformation of

visco-elastic members

between 2 pendulums

is used. Weight 3.2 t, adjustment of period

possible. Placed at a height or lUUm. 5 is increased to 0.17

0 0 0 PD type

0 Norderelbe Bridge

(cable stay bridge 64 +

172 + 64 m, single plane

suspension). Vibration

of tower above the

upper cable point was observed (30 m).

Vibration frequency 1.93 Hz (X), 1.1 Hz (Y). 5 =

0.02

A pendulum weighing

490 kg (mass ratio

0.076) which can swing

in both directions was

placed within the

tower after adjusting

the frequency of

oscillations to that of the tower. Damper

provided. 5 is increased to 0.1

0 0 The tower

top cross

section was 1.13m X 1.13m

-110-
1 2 3 4 5 6 7 8 9 10 D4: Spring mass type

0 Pedestrian Bridge

(West Germany, cable

stay bridge, 90 + 28 + 22

m) Flexural vibrations: Primary: 0.86 Hz: 6 =

0.096; Secondary: 1.72 Hz; 5 =0.029

Bronx-Whitestone

Bridge (suspension

bridge, central span

701m). Flexural

vibrations of stiffening

girder. Danger of

damage at V > 31 m/sec

TMD was made from

a 2700 kg plumb

weight (primary mass

ratio 0.0184) supported

by coil spring.

Damper provided.

Primary 6 = 0.38; Secondary almost

doubled

8 plumb weights, each

11 t were suspended

inside the girder using

springs

0

0

0

0

Example of pedestrian

bridge in West

Germany:

Kessock

bridge

Information avail- able only on proposed

structures. Real

structures are still awaited

D5:

Hydraulic

support

Block type

0 Citi Corp Center (New

York, 63 story building).

Gust response.

Vibration frequency of

primary bending mode

for two principal axes

0.145 Hz and 0.139 Hz. h= 0.01

373 t concrete block

(mass ratio = 0.02) is supported

hydraulically in

horizontal direction

along both axes and

has stroke of 2.3m.

Using the

compression air

spring, resonance

adjustment in both

directions is possible,

h increased to 0.04

0 0 Equipped

in February

1978. Trigger

level is an

acceleration of 0.003 g at 63rd

floor

0 John Hancock Tower

(Boston 60 stories).

Bending and torsional

modes in east-west

direction

Two 273 t lead boxes

kept on 58th floor at a distance of 60m. The

mechanism is the same as that at Citi Corp Center

0 0 Construct- ed in June

1977

J'

E. Active

Response

Control

El: External

force type

- Tower-like structure The controlling force

is applied to structure by external means

such as ropes, rods,

springs, etc. The

detection of vibrations

and corresponding

actuator drive control

is essential

0

-111-
1 2 3 4 5 6 7 8 9 10

E2: Internal

force type

Cable stay bridge.

Fluttering, gust

response

Controlling force is generated using

electro-hydraulic servo-actuators placed

below cable ends.

Critical wind velocity

of fluttering increased.

Gust response

reduced.

0

E3: Active

TMD type

- Multistoried building

Gust response

An actuator is placed

between TMD and

structure such that

optimum controlling

force is exerted after vibrations are

detected. Compared

with passive TMD, the same effect can be

achieved with smaller mass or shorter stroke

0

E4: Semiactive

TMD type

- Multistory building.

Gust response

A control valve is provided to the TMD

damper making it a damper with variable

coefficient of

damping. Control for maximum damping is obtained after sensing

the vibrations. While

retaining the merits of active TMD, the

power requirements

are reduced thus

simplifying the device.

0

Notes: Precedent: Symbol 0 means that the method considered has never been

applied to real structures.

Symbols: A—During construction; B~After completion; C~During construction; D~

After completion; V~Wind velocity; Vcr—Critical wind velocity; f~Vibration

frequency; 5~Logarithmic damping ratio; h~Damping constant; TMD~Tuned-mass

damper. Mass ratio—Reduced mass ratio; Damper—Oil damper, vibration absorber,

etc.

-112-
APPENDIX 3

BIBLIOGRAPHY

1. Matsuda, Tanemitsu; Haruhiko Tohara; Mizuho Tanaka; Michiyuki Kawano and

others. 1963. Experimental studies about rubber supports (1). Doboku Gijutsu,

18:5-10

2. Matsuda, Tanemitsu; Haruhiko Tohara; Mizuho Tanaka; Michiyuki Kawano and

others. 1963. Experimental studies about rubber supports (2). Doboku Gijutsu,

18: 21-24.

3. Kawamata, Shigeya. 1972. Studies about prevention of disaster and vibration

harassment in cities. 1-5. Whether base isolation structure is possible? Rinji

Tigyo lin Kai Kenkyu Hokoku, March, pp. 1-17.

4. Izumi, Masanori and Yoichi Kishimoto. 1975. Studies about damping of

vibrations in buildings. Tohoku Daigaku Kenchikugakuho, March, pp. 67-80.

5. Kawamata, Shigeya. 1975. Studies about response-control mechanisms. Proposal

of a new antiseismic unit using mass pump. Nippon Zosen Gakkai-shi, No.

547, pp. 7-13.

6. Derham, C.J.; L.R. Wootton and S.B.B. Learovd. 1975. Vibration insulation and

antiseismic protection of buildings using natural rubber multings. Nippon

Gomu Kyokai-shi. 48: 219-223.

7. Lindly, P.B. 1975. Natural rubber bearings for bridge. Nippon Gomu Kyokai-shi,

48: 91-95.

8. Tohara, Haruhiko. 1976. Elasticity and spring hardness of vulcanized rubber.

Nippon Gomu Kyokai-shi, August, 49: 415-419.

9. Yoshizawa, Tsukasa. 1976. Design of vibration-insulation rubber and selection of

material (Part 1). Nippon Gomu Kyokai-shi, 49: 7-16.

10. Yoshizawa, Tsukasa. 1976. Design of vibration-insulation rubber and selection of

material (Part 2). Nippon Gomu Kyokai-shi, 49: 309-326.

-113-
11. Matsushita, Kiyoo; Hiroshi Nishiuchi; Tatsuo Sasaki and Masanori Izumi. 1977.

Restoring-force characteristics of steel-bar damper. Nippon Kenchiku Gakkai

Taikai.

12. Yamada, Junkichi. 1977. Natural rubber as an engineering material. Nippon

Gomu Kyokai-shi, 50: 467-483.

13. Saito, Akira; Yushichi Miura; Koichiro Bando; Toshio Kikuchi and Yozo Goto.

1978. Behavior of a sliding vibration-isolator equipment used in foundations.

5th TEES, pp. 897-904.

14. Nakagawa, Kyoji; Seiji Watanabe; Seisaburo Shimaguchi; Nobuo Yamashita;

Hisazumi Yasui and Chikara Iniwa. 1978. Experimental studies about dynamic

floor system (Part 1) - Sinusoidal forced vibration experiment on a large-scale

model. Obayashi-gumi Gijutsu Kenkyusho-ho No. 16, pp. 46-50.

15. Nakagawa, Kyoji; Seiji Watanabe and Shozaburo Shimaguchi. 1978.

Experimental studies about dynamic floor system (Part 2) Full-scale shaking

table test on computers. Obayashi-gumi Gijutsu Kenkyusho-ho, No. 17, pp. 17-

21.

16. Anzai, Katsuhiko and Hideyuki Tada. 1980. Discussions about aseismic isolator

(steel rubber lamination pad). Nippon Kenchiku Gakkai Taikai.

17. Shimazu, Takayuki and Hideo Araki. 1980. Basic experimental studies on

vibration insulation properties of layered walls. Nippon Kenchiku Gakkai

Taikai, September, pp. 755-757.

18. Izumi, Masanori; Hirozo Mitsuhashi; Tatsuo Sasaki; Hiroshi Katsukura and

Fusatoshi Aizawa. 1980. Studies about damping of vibrations in buildings.

Basic studies about energy dissipation-type structure. Nippon Kenchiku

Gakkai, Tohoku-shibu, February, pp. 85-88.

19. Matsushita, Kiyoo; Akio Kurakata; Masanori Izumi; Mareaki Nomura and

Tatsuo Sasaki. 1980. Restoring-force characteristics of steel pipe damper.

Nippon Kenchiku Gakkai, Tohoku-shibu, March, pp. 129-132.

20. Mori, Masahide; Tsuyoshi Arano; Takeshi Kataoka; Kanehiro Ochiai and Hiroaki

Kasai. 1980. Base isolation structure incorporating sliding elements and rubber

in the foundations of buildings (Part 1). Nippon Kikai Gakkai Koen Ronbunshu. No. 800-3, pp. 86-88.

21. Kumagai, Koji; Tsuyoshi Arano; Masaki Kurihara and Hiroaki Kasai. 1980. Base

isolation structure incorporating sliding elements and rubber in the

foundations of buildings (Part 2. Rocking vibrations developed at the time of

sliding). Nippon Kikai Gakkai Koen Ronbun-shu, No. 800-3, pp. 89-91.

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22. Kumagai, Koji; Tsuyoshi Arano; Masaki Kurihara and Hiroaki Kasai. 1980. Base

isolation structure incorporating sliding elements and rubber in the

foundations of buildings (Part 3. Methods of response analysis in multi-degreeof freedom systems and comparison with experimental findings). Nippon

Kikai Gakkai Koen Ronbun-shu, No. 800-3, pp. 92-94.

23. Fujita, Takafumi; Shinobu Hattori and Jiro Ishida. 1980. Studies about vibration

isolating floor using pre-stretched or pre-compressed springs (Part 1 . Vibration

characteristics and vibration isolator properties I). Seisan Kenkyu, August, Vol.

32, No. 8, pp. 48-51.

24. Fujita, Takafumi. 1980. Studies about vibration isolating floor using prestretched and pre-compressed springs (Part 2. Vibration characteristics and

vibration isolator properties II). Seisan Kenkyu, October, Vol. 32, No. 10, pp. 28-

31.

25. Fujita, Takafumi; Shinobu Hattori and Jiro Ishida. 1980. Studies about vibration

isolating floor using pre-stretched or pre-compressed springs (Part 3. Vibration

characteristics and vibration isolator properties. III). Seisan Kenkyu, December,

Vol. 32, No. 12, pp. 22-25.

26. Anzai, Katsuhiko and Hideyuki Tada. 1980. Discussions about aseismic isolator

(steel rubber lamination pad). Nippon Kenchiku Gakkai Taikai, September, pp.

751-753.

27. Izumi, Masanori; Hirozo Mitsuhashi; Tatsuo Sasaki; Hiroshi Katsukura and

Fusatoshi Aizawa. 1981. Studies about damping of vibrations in buildings.

Basic studies about energy dissipation-type structure. Nippon Kenchiku

Gakkai, Tohoku-shibu, February.

28. Matsushita, Kiyoo; Masanori Izumi; Hirozo Mitsuhashi; Fusatoshi Aizawa and

Tatsuo Sasaki. 1981. Restoring-force characteristics of steel pipe damper. (Part

2). Nippon Kenchiku Gakkai, Tohoku-shibu, February, pp. 161-164.

29. Fujita, Takafumi; Shinobu Hattori and Jiro Ishida. 1981. Studies about vibration

isolating floor using pre-stretched or pre-compressed springs (Part 4. Experiments on large model - 1). Seisan Kenkyu, Vol. 33, No. 2.

30. Fujita, Takafumi; Shinobu Hattori and Jiro Ishida. 1981. Studies about vibration

isolating floor using pre-stretched or pre-compressed springs (Part 5. Experiments on large model - II). Seisan Kenkyu, February, Vol. 33, No. 2, pp.

24-27.

31. Fujita, Takafumi and Shinobu Hattori. 1981. Studies about vibration isolating

floor using pre-stretched or pre-compressed springs (Part 6. Analysis of large

vibration isolating floor - 1). Seisan Kenkyu, July, Vol. 33, No. 7, pp. 35-39.

-115-
32. Fujita, Takafumi and Shinobu Hattori. 1982. Studies about vibration isolating

floor using pre-stretched or pre-compressed springs (Part 7. Analysis of large

vibration isolating floor - 11) Seisan Kenkyu, February, Vol. 34, No. 4, pp. 18-21.

33. Shimizu, Nobuyuki; Shizuo Yamamoto; Fiji Kawada and Yuichi Nagai. 1982.

Theoretical studies of vibration isolator equipment based on the pendulum and

lever action. 6th TFES.

34. Anzai, Katsuhiko; Hideyuki Tada and Shiro Tatara. 1981. Discussions about

aseismic isolator. Part 2. Model experiment of isolator. Nippon Kenchiku

Gakkai Taikai, September, pp. 775-777.

35. Anzai, Katsuhiko; Hideyuki Tada and Shiro Tatara. 1981. Discussions about

aseismic isolator. Part 3. Discussions on model experiment. Nippon Kenchiku

Gakkai Taikai, September, pp. 777-77%.

36. Anzai, Katsuhiko; Hideyuki Tada and Shiro Tatara. 1981. Discussions about

aseismic isolator. Part 4. Static experiment with a large isolator. Ni ppon

Kenchiku Gakkai Taikai, September, pp. 779-780.

37. Tada, Hideyuki; Mineo Takayama and Shiro Tatara. 1982. Discussions about

aseismic isolator. Part 5. Model experiment with isolator 2. Nippon Kenchiku

Gakkai Taikai, October, pp. 781-782.

38. Tada, Hideyuki, Mineo Takayama and Shiro Tatara. 1982. Discussions about

aseismic isolator. Part 6. Discussions on model experiment. Nippon Kenchiku

Gakkai Taikai, October, pp. 783-784.

39. Tada, Hideyuki; Mineo Takayama and Shiro Tatara. 1982. Discyssions about

aseismic isolator. Part 7. Static experiment on large isolator. Nippon Kenchiku

Gakkai Taikai. October, pp. 785-786.

40. Tada, Hideyuki; Katsutoshi Ando and Shiro Tatara. 1983. Discussions about

aseismic isolator. Part 8. Model experiment with isolator 3. Nippon Kenchiku

Gakkai Taikai, September, pp. 893-894.

41. Tada, Hideyuki; Yasuhito Kawasaki and Hirofumi Tai. 1981. Model experiment

with aseismic isolator. Part 1. Static load test on isolator. Nippon Kenchiku

Gakkai, Chugoku Kyushu-shibu, March, pp. 137-140.

42. Tada, Hideyuki; Kenji Jinnai and Shiro Tatara. 1981. Model experiment with

aseismic isolator. Part 2. Dynamic properties of isolator. Nippon Kenchiku

Gakkai, Chugoku Kyushu-shibu, March, pp. 141-144.

43. Tada, Hideyuki and Shinji Sera. 1981. Model experiment with aseismic isolator.

Part 3. Model tests on the vibration in buildings due to seismic waves. Nippon

Kenchiku Gakkai, Chugoku Kyushu-shibu, March, pp. 142-152.

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44. Kitazawa, Koji; Akio Ikeda; Soichi Kawamura and Shinobu Ito. 1981. Studies

about Taisei-type vibration isolator structure (TASS system). Taisei Kensetsu

Giiutsu Kenkyusho Hokoku, No. 14, pp. 117-126.

I

45. Ikeda, Akio; Soichi Kawamura; Koji Kitazawa and Masami Takagi. 1981. Studies

about vibration isolator structure (Part 1).. Outline of TASS system. Nippon

Kenchiku Gakkai Taikai, September, pp. 771-772.

46. Ikeda, Akio; Soichi Kawamura; Koji Kitazawa and Masami Takagi. 1981. Studies

about vibration isolator structure (Part 2). Shaking table tests on TASS system.

Nippon Kenchiku Gakkai Taikai, September, pp. 773-774.

47. Izumi, Masanori. 1981. Studies about vibration damping methods in buildings.

Tohoku Daigaku Kenchiku Gakuho, pp. 63-79.

48. Usami, Tamio; Etsuko Nagano; Masao Watanabe; Toshiyuki Kitta; Mitsuo

Yonehama and Kuniaki Hayashi. 1981. Aging deterioration in rubber supports

and static properties. Nippon Gomu Kyokai-shi, May, pp. 174-183.

49. Usami, Tamio; Etsuko Nagano; Masao Watanabe; Toshiyuki Kitta; Mitsuo

Yonehama and Kuniaki Hayashi. 1982. Aging deterioration in rubber supports

and effect of live load. Nippon Gomu Kyokai-shi, March, pp. 777-783.

50. Obo, Naoto and Tsuneo Katayama. 1981. Properties of elastic waves propagating

through trenches. Seisan Kenkyu, March, Vol. 33, No. 3, pp. 29-32.

51. Omori, Naoto and Tsuneo Katayama. 1981. Isolation of elastic waves due to cracks. Seisan Kenkyu, May, Vol. 33, No. 5, pp. 36-39.

52. Shimosaka, Haruo and Takafumi Fujita. 1982. Design of aseismic stoppers

provided to resiliently supported machine. 6th TEES.

53. Kitazawa, Koji; Akio Ikeda and Soichi Kawamura. 1982. Studies about vibration

isolator structure, 6th TEES, pp. 1481-1489.

54. Kurihara, Masaki; Takeshi Kataoka; Hiroaki Kasai; Tsuyoshi Niino and Koji

Kumagai. 1982. Basic study of vibration isolator structure in an atomic power

plant, 6th TEES, pp. 1465-1472.

55. Fujita, Takafumi; Satoshi Fujita and Toshikazu Yoshizawa. 1982. Vibration

isolator supports of heavy machinery employing laminated rubber. (Part 1. Basic studies about the vibration isolator support devices - I). Seisan Kenkyu,

February, Vol. 34, No. 2, pp. 64-67.

56. Fujita, Takafumi; Satoshi Fujita and Toshikazu Yoshizawa. 1982. Vibration

isolator supports of heavy machinery employing laminated rubber. (Part 2. Basic studies about the vibration isolator support devices - 2). Seisan Kenkyu,

September, Vol. 34, No. 9, pp. 413-416.

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57. Fujita, Takafumi; Satoshi Fujita; Toshikazu Yoshizawa and Shigenori Suzuki.

1983. Vibration isolator supports of heavy machinery employing laminated

rubber. (Part 3. Basic studies about the system using vibration isolator supports

- 2) Seisan Kenkyu, February, Vol. 35, No. 2, pp. 108-111.

58. Fujita, Takafumi; Satoshi Fujita; Toshikazu Yoshizawa and Shigenori Suzuki.

1983. Vibration isolator supports of heavy machinery employing laminated

rubber. (Part 4. Response analysis of the system using vibration isolator

supports). Seisan Kenkyu, March, Vol. 35, No. 3, pp. 134-136.

59. Fujita, Takafumi; Satoshi Fujita and Toshikazu Yoshizawa. 1982. Vibration

isolator supports of heavy machinery employing laminated rubber. (Part 1. Basic structure of vibration isolator support and preliminary analysis). Nippon

Kikai Gakkai Koen Ronbun-shu, No. 820-4, pp. 123-125.

60. Fujita, Takafumi; Satoshi Fujita and Toshikazu Yoshizawa. 1982. Vibration

isolator supports of heavy machinery employing laminated rubber. (Part 2. Basic experiments on the large vibration isolator supporting devices). Nippon

Kikai Gakkai Koen Ronbun-shu, No. 820-13, pp. 86-88.

61. Fujita, Takafumi; Satoshi Fujita; Toshikazu Yoshizawa and Shigenobu Suzuki.

1982. Development of vibration isolator support devices using laminated

rubber. 6th TEES, pp. 1489-1495.

62. Yamagata, Makoto; Yuichi Nagai; Shizuo Yamamoto; Nobuyuki Shimizu; Fiji

Kawada and Masami Oshima. 1983. Vibration isolator device using the

pendulum-and-lever. Theoretical studies when elastic vibration isolator

devices are connected to elastic multistory structures. Nippon Kenchiku

Gakkai Taikai.

63. Yamagata, Makoto; Yuichi Nagai; Shizuo Yamamoto; Nobuyuki Shimizu; Eiji

Kawada and Masami Oshima. 1983. Vibration isolator device using the

pendulum-and-lever (when used in case of single-story building having perfect

elasto-plastic restoring-force characteristics). Nippon Kenchiku Gakkai Taikai.

64. Yamagata, Makoto; Eiji Kawada and Yuichi Nagai. 1982. Experimental studies in

vibration isolator device using the pendulum-and-lever. 6th TEES, pp. 1497-

1504.

65. Shimizu, Nobuyuki; Eiji Kawada; Makoto Yamagata; Sizuo Yamamoto and

Yuichi Nagai. 1983. Theoretical studies in a case where vibration isolator

devices are used in a single-story building. Vibration isolator device using the

pendulum-and-lever. Nippon Kenchiku Gakkai Ronbun Hokoku-shu, May,

No. 327, pp. 29-39.

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66. Yamagata, Makoto; Sizuo Yamamoto; Eiji Kawada; Yuichi Nagai and Masami

Oshima. 1983. Vibration isolator device using the pendulum-and-lever (when

used in case of single-story building having perfect elasto-plastic restoring-force

characteristics). Nippon Kenchiku Gakkai Taikai, pp. 901-902.

67. Shimizu, Nobuyuki; Sizuo Yamamoto; Eiji Kawada; Yuichi Nagai; Makoto

Yamagata and Masami Oshima. 1983. Vibration isolator device using the

pendulum-and-lever. Theoretical studies when elastic vibration isolator

devices are connected to elastic multistor}-^ structures. Nippon Kenchiku

Gakkai Taikai, September, pp. 899-900.

68. Tada, Hideyuki; Mineo Takayama; Shoichi Yamaguchi; Zenten Ando and Shiro

Tatara. 1983. Full-scale experiments about vibration isolator structure (Part 1). Over-all planning. Nippon Kenchiku Gakkai Taikai, September, pp. 887-888.

69. Tada, Hideyuki; Mineo Takayama; Shoichi Yamaguchi; Zenten Ando and Shiro

Tatara. 1983. Full-scale experiments on vibration isolator structure (Part 2).

Results of experiments. Nippon Kenchiku Gakkai Taikai, September, pp. 889-

890.

70. Tada, Hideyuki; Mineo Takayama; Shoichi Yamaguchi; Zenten Ando and Shiro

Tatara. 1983. Full-scale experiments on vibration isolator structure (Part 3).

Analysis of test results. Nippon Kenchiku Gakkai Taikai, September, pp. 891-

892.

71. Fujita, Takafumi; Kunihiko Yogo and Toshio Omi. 1983. Studies about vibration

isolator devices using linear motion mechanism. Part 1. Structure of vibration

isolator device and its vibration properties. Seisan Kenkyu, April, Vol. 35,

No. 4.

72. Fujita, Takafumi; Kunihiko Yogo and Toshio Omi. 1983. Studies about vibration

isolator devices using linear motion mechanism. Part 2. Seismic wave

excitation experiment and response analysis. Seisan Kenkyu, May, Vol. 35, No.

5, pp. 212-215.

73. Fujita, Takafumi; Kunihiko Yogo; Takayuki Koizumi and Toshio Omi. 1983.

Studies about vibration isolator devices using linear motion mechanism. Part

3. Application to electric control panel of atomic power plant. Seisan Kenkyu,

July, Vol. 35, No. 7, pp. 344-347.

74. Fujita, Takafumi; Satoshi Fujita; Toshikazu Yoshizawa and Shigenobu Suzuki.

1983. Vibration isolator supports of heavy machinery employing laminated

rubber. (Part 4. Response analysis of the system using vibration isolator

supports). Seisan Kenkyu, Vol. 35, No. 3.

75. Fujita, Takafumi and Sadayuki Kuramoto. 1983. Vibration experiment on a three-dimensional vibration isolator device and response measurement under

natural earthquake. Seisan Kenkyu, Vol. 35, No. 9, pp. 447-449.

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76. Fujita, Takafumi; Shinobu Hattori and Jiro Ishida. 1983. Studies about vibration

isolating floor using pre-stretched springs. (Part 1. a Basic studies about

vibration isolator devices). Nippon Kikai Gakkai Koen Ronbun-shu, Sec. C,

May, Vol. 49, No. 441, pp. 727-736.

77. Fujita, Takafumi; Shinobu Hattori and Jiro Ishida. 1983. Studies about vibration

isolating floor using pre-stretched springs. (Part 2. Experiment using full-scale

model). Nippon Kikai Gakkai Koen Ronbun-shu, Sec. C, May, Vol. 49, No. 441,

pp. 737-744.

78. Fujita, Takafumi and Shinobu Hattori. 1983. Studies about vibration isolating

floor using pre-stretched springs. (Part 3. Analysis of a full-scale vibration

isolating floor). Nippon Kikai Gakkai Koen Ronbun-shu, Sec. C, May, Vol. 49,

No. 441, pp. 745-754.

79. Miyake, Hiraku; Satoru Aizawa and Yutaka Hayamizu. 1983. Study of vibration

isolator support devices using laminated rubber. Study of energy absorption

equipment (Part 1.) Nippon Kenchiku Gakkai Taikai, September, pp. 895-896.

80. Asai, Koichi; Yoshio Tanno; Tadahiro Yano; Yutaka Hayamizu; Satoru Aizawa

and Hiraku Miyake. 1983. Vibration isolator support devices using cylindrical

rubber and viscous shear-resistance. Nippon Kenchiku Gakkai Taikai,

September, pp. 897-898.

81. Fujita, Takafumi. 1983. Recent trends in antiseismic design, outside Japan and

application of vibration isolator structure in atomic power plants. ICU

Genshiryoku Seminar, March, pp. 1-52.

82. Moriyama, Takeo. 1983. Details of antiseismic designs used overseas and their

trend. ICU Genshiryoku Seminar, March, pp. 1-76.

83. Yoshida, Noboru and Kiyokazu Sakai. 1983. The stress-strain relationship in

rubber-lined metal wares and shape function. Nippon Gomu Kyokai-shi,

October, Vol. 56, pp. 369-380.

84. Hayamizu, Yutaka; Satoru Aizawa; Masahiko Higashino and Yasuhiko Abe.

1984. Study of vibration isolator support devices using laminated rubber.

Experiment on large model. (Part 1. Properties of laminated rubber). Nippon

Kenchiku Gakkai Taikai, October, pp. 1017-1018.

85. Izumi Masanori. 1984. Past, present and future of vibration isolator. Nippon

Kenchiku Gakkai, Tohoku-shibu Kenkyu Happyo-kai, March.

86. Izumi, Masanori; Hiroshi Fujikura; Masahiko Kimura and Mika Kaneko. 1984.

Random response of the spring-mass system having hysteresis type damping

mechanism at the base. Nippon Kenchiku Gakkai, Tohokushibu Kenkyu

Happyo-kai, March.

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87. Izumi, Masanori; Hirozo Mitsuhashi; Hiroshi Katsukura and Masahiko Kimura.

1984. Basic studies about vibration damping systems for structures in urban

areas. Tohoku Daigaku Kenchiku Gakuho, March, No. 23.

88. Hayamizu, Yutaka; Satoru Aizawa; Masahiko Higashino and Yasuhiko Abe.

1984. Study of vibration isolator support devices using laminated rubber.

Experiment using large model. (Part 2. Response-control properties). Nippon

Kenchiku Gakkai Taikai, October, pp. 1019-1020.

89. Notake, Masayoshi and Yutaka Osawa. 1984. Studies about vibration properties

of vibration isolator structure and seismic input force (Part 1). Nippon

Kenchiku Gakkai Taikai, October, pp. 1015-1016.

90. Okada, Hiroshi; Tomohiko Tsunoda; Matsutaro Seki; Akira Teramura; Takashi

Nakamura and Arihide Nobata. 1984. Studies about vibration isolation in

structures. (Part 1. Total plan). Nippon Kenchiku Gakkai Taikai, October, pp.

1007-1008.

91. Okada, Hiroshi; Tomohiko Tsunoda; Matsutaro Seki; Akira Teramura; Takashi

Nakamura and Arihide Nobata. 1984. Studies about vibration isolation in

structures. (Part 2. Static experiments). Nippon Kenchiku Gakkai Taikai,

October, pp. 1009-1010.

92. Okada, Hiroshi; Tomohiko Tsunoda; Matsutaro Seki; Akira Teramura; Takashi

Nakamura and Arihide Nobata. 1984. Studies about vibration isolation in

structures. (Part 3. Experiment about dynamic characteristics). Nippon

Kenchiku Gakkai Taikai, October, pp. 1011-1012.

93. Okada, Hiroshi; Tomohiko Tsunoda; Matsutaro Seki; Akira Teramura;

Nakamura and Arihide Nobata. 1984. Studies about vibration isolation in

structures. (Part 4. Experiment for earthquake response). Nippon Kenchiku

Gakkai Taikai, October, pp. 1013-1014. . .

94. Osaki, Yorihiko; Teruo Sawada; Yasushi Nukii; Masuhiko Kobatake; Yoshio

Koyanagi; Nobuo Fukuw^a and Kazuo Tamura. 1984. Studies about vibration

isolator structure in atomic power plant. (Part 1 . Basic dynamic properties of a single-mass system model). Nippon Kenchiku Gakkai Taikai, October, pp. 2289-

2290.

95. Osaki, Yorihiko; Teruo Saw^ada; Yasushi Nukii; Masuhiko Kobatake; Yoshio

Koyanagi; Nobuo Fukuwa and Toshiaki Sato. 1984. Studies about vibration

isolator structure in atomic power plant. (Part 2. Study of the response

characteristics of the upper part of building using multi-degree of freedom

system model). Nippon Kenchiku Gakkai Taikai, October, pp. 2291-2292.

96. Fujita, Takafumi. 1984. Is vibration isolator useful? Kikai no Kenkvu, Vol. 36,

No. 1, pp. 91-97.

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97. Izumi, Masanori. 1984. Application of vibration isolator structure in automatic

furnaces. Lecture Note. Nippon Genshiryoku Toho Center.

98. Horiguchi, Jun'ichi; Yasuhiro Yamamoto and Tetsu Hashimoto. 1984. Study of

electric transformer with reference to vibration isolator slide devices.

Denryoku Doboku. May, No. 190, pp. 19-28.

99. Shirai, Masaaki; Kazushige Ishino and Koryu Ikeuchi. 1984. Estimation of effect

of vibration absorption device used in bridges, using step excitation method

and analysis by parts. Nippon Kikai Gakkai Ronbun-shu, April, pp. 737-743.

100. Yamaoka, Norio. 1984. Recent increase in using dynamic vibration absorbing

devices for effective suppression of vibrations - Prominent advancement of

design theory. Nikkei Mechanical, August, pp. 98-103.

101. Matsutaro, Seki; Toshikazu Takeda; Hiroshi Okada; Tomohiko Tsunoda;

Takashi Nakamura; Hiraku Uchida and Akira Teramura. 1985. Studies about

vibration isolation in structure. Part 5. Static experiments using large-scale

rubber laminates. Nippon Kenchiku Gakkai Taikai, pp. 483-484.

102. Uchida, Hiraku; Toshikazu Takeda; Hiroshi Okada; Tomohiko Tsunoda;

Matsutano Seki; Takashi Nakamura and Akira Teramura. 1985. Studies

about vibration isolation in structure. Part 6. Static experiments with full

size damper. Nippon Kenchiku Gakkai Taikai, pp. 485-486.

103. Nobata, Arihide; Akira Teramura; Tomohiko Tsunoda; Toshikazu Takeda;

Hiroshi Okada; Takashi Nakamura and Matsutaro Seki. 1985. Studies about

vibration isolation in structure. Part 7. Observation of structure during

earthquake. Nippon Kenchiku Gakkai Taikai, pp. 487-488.

104. Nakamura, Takashi; Toshikazu Takeda; Yoshio Fujita; Hiroshi Okada;

Matsutaro Seki; Akira Teramura and Arihide Nobata. 1985. Studies about

vibration isolation in structure. Part 8. Study of vibration isolator device

equipped in a single-mass system model. Nippon Kenchiku Gakkai Taikai,

pp. 489-490.

105. Yasaka, Atsuhiko; Masakuni Yoshida; Hiroshi Koshida; Hajime Ando; Masao

lizuka; Kiyomi Horikoshi and Nobuo Fujimoto. 1985. Development of

vibration isolation methods for buildings. Part 1. Basic approach. Nippon

Kenchiku Gakkai Taikai, pp. 491-492.

106. lizuka, Masao; Atsuhiko Yasaka; Katsuhiko Takahisa; and Toshikazu

Yoshizawa. 1985. Development of vibration isolation methods for buildings.

Part 2. Static, dynamic experiments with rubber laminates. Nippon

Kenchiku Gakkai Taikai, pp. 493-494.

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107. Hayashi, Shoji and Yoichi Matsumoto. 1985. Study of parameters affecting

basic properties of rubber laminates, which is a component of vibration

isolator device. Nippon Kenchiku Gakkai Taikai, pp. 495-496.

108. Aizawa, Satoru; Masahiko Higashino; Yutaka Hayamizu; and Yasuhiko Abe.

1985. Study of vibration isolator support devices using laminated rubber.

Experiment v^ith a large model. Part 3. Vibration properties during

earthquake. Nippon Kenchiku Gakkai Taikai, pp. 497-498.

109. Higashino, Masahiko; Satoru Aizawa and Yutaka Hayamizu. 1985. Study of

vibration isolator support devices using laminated rubber. Experiment with a large model. Part 4. Simulation analysis. Nippon Kenchiku Gakkai Taikai,

pp. 499-500.

110. Tada, Hideyuki; Akira Sakai; Katsutoshi Ando and Tetsuro Ito. 1985.

Experiments on an existing vibration isolated structure. Part 5. Planning of a shaking-table test. Nippon Kenchiku Gakkai Taikai, pp. 501-502.

111. Sakai, Akira; Hideyuki Tada; Keiko Morita and Mineo Takayama. 1985.

Experiments on an existing vibration isolated structure. Part 6. Discussion on

the results of experiment. Nippon Kenchiku Gakkai Taikai, pp. 503-504.

112. Osada, Kaio; Masayoshi Notake; Michihiro Ohori and Yutaka Osawa. 1985.

Vibration properties of vibration isolated structures. Part 1. Results of

measurement of microtremors. Nippon Kenchiku Gakkai Taikai, pp. 505-506.

113. Notake, Masayoshi; Kaio Osada; Michihiro Ohori and Yutaka Osawa. 1985.

Vibration properties of vibration isoalted structures. Part 2. Threedimensional model analysis. Nippon Kenchiku Gakkai Taikai, pp. 507-508.

114. Uchida, Kazuyoshi; Kaoru Mizukoshi; Yasuo Takenaka and Katsuhiko Emori.

1985. Dynamic behavior of nuclear power plant founded on sliding elastomer

bearing pads. Part 1 . Outline of vibration isolator structure and its modelling.

Nippon Kenchiku Gakkai Taikai, pp. 509-510.

115. Mizukoshi, Kaoru; Kazuyoshi Uchida; Yasuo Takenaka; Kiyoshi Horikomi; J. Betbeder Matibet; J.P. Noel Leroux and P. Ukrich. 1985. Dynamic behavior of

nuclear power plant founded on sliding elastomer bearing pads. Part 2. Nonlinear earthquake response analysis. Nippon Kenchiku Gakkai Taikai,

pp. 511-512.

116. Takahashi, Ikuo; Yoshio Koyanagi; Nobuo Fukuwa and Hiroshi Kawase. 1985.

Response of vibration isolated atomic furnace building to inputs with phase

difference. Part 1. Transfer function of the building. Nippon Kenchiku

Gakkai Taikai, pp. 513-514.

-123-
117. Takahashi, Ikuo; Yoshio Koyanagi; Nobuo Fukuwa and Hiroshi Kawase. 1985.

Response of vibration isolated atomic furnace building to inputs with phase

difference. Part 2. Response of building and vibration isolator device.

Nippon Kenchiku Gakkai Taikai, pp. 515-516.

118. Kobatake, Masuhiko; Yorihiko Osaki; Temo Saw^ada; Yoshio Koyanagi and

Yasuo Okada. 1985. Studies about vibration isolator structure in atomic

pow^er plant. Part 3. Study about the restoring-force characteristics of

vibration isolator device to be used in atomic furnace room. Nippon

Kenchiku Gakkai Taikai, pp. 517-518. ,

119. Okada, Yasuo; Yorihiko Osaki; Temo Sawada; Yoshio Koyanagi and Masuhiko

Kobatake. 1985. Studies about vibration isolator structure in atomic power

plant. Part 4. Study of relative displacement between vibration isolator

atomic furnace room and turbine room. Nippon Kenchiku Gakkai Taikai,

pp. 519-520.

120. Matsuda, Taiji; Sakae Aoyagi and Tetsu Shiomi. 1985. Survey of vibration

isolator structure. October. Denryoku Central Research Laboratory, Research

Report No. 385010.

121. Kawamata, Shigeya and Masaaki Onuma. 1986. Controlling the vibrations in

structure using inertia pump damper. Part 1. Theoretical model and

response to sinusoidal excitation. Nippon Kenchiku Gakkai Taikai, pp. 771-

772.

122. Mori, Kenji; Shigeya Kawamata; Yoshihiro Abe and Masaaki Onuma. 1986.

Controlling the vibrations in structure using inertia pump damper. Part 2. Inertia pump damper with a gap and its effect. Nippon Kenchiku Gakkai

Taikai, pp. 773-774.

123. Uno, Tatsuo; Kiyoshi Nagai; Masatake Ichikawa and Toshihiro Koide. 1986.

Basic studies about dampers used for Menshin structures. Part 1. Static

experiment with semicircular steel response-control. Nippon Kenchiku

Gakkai Taikai, pp. 775-776.

124. Inoue, Takashi; Kiyoshi Nagai; Akio Miyoshi and Toshihiro Koide. 1986. Basic

studies about dampers used for Menshin structures. Part 2. Experiment to ascertain the performance of friction damper. Nippon Kenchiku Gakkai

Taikai, pp. 777-77%.

125. Ogino, Nobuyuki; Nobuhiro Machida; Yorimasa Katano; Yoshio Kamiya and

Koji Matsumoto. 1986. Studies about vibration isolator damper Nippon

Kenchiku Gakkai Taikai, pp. 779-780.

-124-
126. Nakamura, Yasukazu; Masaru Sukagawa; Yoichi Matsumoto; Yasuo Inada;

Hiromoto Watanabe and Kazuo Tamura. 1986. Studies about vibration

isolator structure. (Part 1. Properties of vibration isolator unit and

experiments on characteristics of oil damper). Nippon Kenchiku Gakkai

Taikai, pp. 781-782.

127. Morioka, Hiroshi; Masaru Sukagav^^a; Kazuhiko Maebayashi; Masaaki Saruta;

Shoji Hayashi and Yutaka Nakamura. 1986. Studies about vibration isolator

structure. (Part 2. Experiments about properties of steel damper). Nippon

Kenchiku Gakkai Taikai, pp. 783-784.

128. Kaneko, Mika; Masaru Sukagaw^a; Kazuo Tamura and Tetsuji Ito. 1986. Study

about vibration isolator structure. Part 3. Studies about the seismic response

of vibration isolator building. Nippon Kenchiku Gakkai Taikai, pp. 785-786.

129. Saito, Ryo and Mitsuharu Kurata. 1986. Shaking-table test and analysis of twostory building model having friction damper. Nippon Kenchiku Gakkai

Taikai, pp. 787-788.

130. Miyazawa, Hiroshi and Mitsuharu Kurata. 1986. Shaking-table test and

analysis of tv^^o-story building model having collision damper Nippon

Kenchiku Gakkai Taikai, pp. 789-790.

131. Hayashi, Shoji and Yoichi Matsumoto. 1986. Experimental studies about the

rubber laminates using silicone rubber for vibration isolator structure.

Nippon Kenchiku Gakkai Taikai, pp. 791-792.

132. Aizaw^a, Satoshi; Masahiko Higashino; Yutaka Hayamizu and Yasuhiko Abe.

1986. Study of vibration isolator support device using rubber laminates.

Experiments on large model. Part 5. Seismic vibration characteristics (2). Nippon Kenchiku Gakkai Taikai, pp. 793-794. .

133. Higashino, Masahiko; Satoshi Aizav^a and Yutaka Hayamizu. 1986. Study of

vibration isolator support device using rubber laminates. Experiments on

large model. Part 6. Study of viscous damper. Nippon Kenchiku Gakkai

Taikai, pp. 795-796.

134. lizuka, Masao; Atsuhiko Yasaka and Toshikazu Yoshizav^a. 1986.

Development of vibration isolation methods for buildings. (Part 3. Static,

dynamic experiments on a large-size rubber laminate). Nippon Kenchiku

Gakkai Taikai, pp. 797-798.

135. Yasaka, Atsuhiko and Masao lizuka. 1986. Development of vibration isolation

methods for buildings. (Part 4. Experiments with elasto-plastic damper).

Nippon Kenchiku Gakkai Taikai, pp. 799-800.

-125-
136. Fujimoto, Nobuo; Atsuhiko Yasaka; Hiroshi Koshida; Katsuya Igarashi;

Masanori lizuka and Kiyomi Horikoshi. 1986. Development of vibration

isolation methods for buildings. (Part 5. Shaking-table test and analysis).

Nippon Kenchiku Gakkai Taikai, pp. 801-802.

137. Okada, Hiroshi; Toshikazu Takeda; Kazuo Tamura; Matsutaro Seki; Hiraku

Uchida; Tomohiko Tsunoda and Akira Teramura. 1986. Studies about

vibration isolation in structures. (Part 9) Static experiments with large-size

laminated rubber~2. Nippon Kenchiku Gakkai Taikai, pp. 803-804.

138. Nakamura, Takashi; Toshikazu Takeda; Hiroshi Okada; Matsutaro Seki; Hiraku

Uchida; Tomohiko Tsunoda and Akira Teramura. 1986. Studies about

vibration isolation in structures. (Part 10) Dynamic experiment with full- scale laminated rubber. Nippon Kenchiku Gakkai Taikai, pp. 805-806.

139. Uchida, Hiraku; Toshikazu Takeda; Hiroshi Okada; Takashi Nakamura;

Matsutaro Seki; Tomohiko Tsunoda and Akira Teramura. 1986. Studies

about vibration isolation in structures. (Part 11) Dynamic experiments with

full-scale damper. Nippon Kenchiku Gakkai Taikai, pp. 807-808.

140. Seki, Matsutaro; Toshikazu Takeda; Hiroshi Okada; Takashi Nakamura; Hiraku

Uchida; Tomohiko Tsunoda and Akira Teramura. 1986. Studies about

vibration isolation in structures. (Part 12) On-line seismic excitation test with

vibration isolator buildings. Nippon Kenchiku Gakkai Taikai, pp. 809-810.

141. Tada, Hideyuki; Akira Wada; Akira Sakai and Mineo Takayama. 1986.

Experiments on an existing vibration isolator structure. (Part 7) Observation

of seismic waves. Nippon Kenchiku Gakkai Taikai, pp. 811-812.

142. Wada, Akira; Hideyuki Tada; Akira Sakai and Mineo Takayama. 1986.

Experiments on an existing vibration isolator structure. (Part 8) Results of

observation and analytical study. Nippon Kenchiku Gakkai Taikai, pp. 813-

814.

143. Shimizu, Kazuya; Hideyuki Tada; Akira Sakai and Mineo Takayama. 1986.

Experiments on an existing vibration isolator structure. (Part 9) Description

of isolator - 1. Nippon Kenchiku Gakkai Taikai, pp. 815-816.

144. Sakai, Akira; Hideyuki Tada and Mineo Takayama. 1986. Experiments on an

existing vibration isolator structure. (Part 10) Description of isolator - 11. Nippon Kenchiku Gakkai Taikai, pp. 817-818.

'

145. Saeki, Eiichiro; Hideyuki Tada; Akira Sakai and Mineo Takayama. 1986.

Experiments on an existing vibration isolator structure. (Part 11) Description

of steel damper. Nippon Kenchiku Gakkai Taikai, pp. 819-820.

-126-
146. Morita, Keiko; Hideyuki Tada; Akira Sakai and Mineo Takayama. 1986.

Experiments on an existing vibration isolator structure. (Part 12) Description

of lead damper - 1. Nippon Kenchiku Gakkai Taikai, pp. 821-822.

147. Hayakawa Kunio; Hideyuki Tada; Akira Sakai and Mineo Takayama. 1986.

Experiments on description of vibration isolator structure. (Part 13)

Description of lead damper - 11. Nippon Kenchiku Gakkai Taikai, pp. 823-824.

148. Notake, Masayoshi; Kaio Osada; Michihiro Ohori and Yutaka Osawa. 1986.

Vibration properties of vibration isolator structures. (Part 3) Analysis of

microtremors and seismic ground motion record. Nippon Kenchiku Gakkai

Taikai, pp. 825-826.

149. Teramura, Akira and Toshikazu Takeda. 1986. Studies about the dynamic

vibration absorption methods using two mass damper system. Part 1. Basic

outline. Nippon Kenchiku Gakkai Taikai, pp. 827-828.

150. Nobata, Arihide; Akira Teramura and Toshikazu Takeda. 1986. Studies about

the dynamic vibration absorption methods using two mass damper system.

Part 2. Shaking-table confirmation experiment. Nippon Kenchiku Gakkai

Taikai, pp. 829-830.

151. Harada, Hideaki; Masatoshi Suzuki; Takeji Matsumoto; Hisanori Abiru and

Manabu Fujishiro. 1986. Vibration prevention of buildings using damping

mechanism. Part 1 . Model experiment. Nippon Kenchiku Gakkai Taikai, pp.

831-832.

152. Fujishiro, Manabu; Masatoshi Suzuki; Takeji Matsumoto; Hisanori Abiru and

Hideaki Harada. 1986. Vibration prevention of buildings using damping

mechanism. Part 2. Analysis. Nippon Kenchiku Gakkai Taikai, pp. 833-834.

153. Abiru, Hisanori; Masatoshi Suzuki; Takeji Matsumoto; Hideaki Harada and

Manabu Fujishiro. 1986. Vibration prevention of buildings using damping

mechanism. Part 3. Application to experiment. Nippon Kenchiku Gakkai

Taikai, pp. 835-836.

154. Kanayama, Hiroo; Takuji Kobori; Mitsuo Sakamoto; Toshikazu Yamada and

Shuichi Kamagata. 1986. New developments in design of antiseismic

structures. Approach towards dynamic intelligent buildings. Nippon

Kenchiku Gakkai Taikai, pp. 837-838.

155. Kamagata, Shuichi; Takuji Kobori; Hiroo Kanayama; Mitsuo Sakamoto and

Toshikazu Yamada. 1986. Step towards dynamic intelligent building. D.I.B. using variable stiffness mechanism. Nippon Kenchiku Gakkai Taikai, pp.

839-840.

-127-
156. Yoshikawa, Takeo and Seiji Watanabe. 1986. Studies about design of

multistoried buildings with damping devices. Nippon Kenchiku Gakkai

Taikai, pp. 841-842. , ,

157. Ohori, Michihiro; Tadao Minami and Yutaka Osawa. 1986. Studies about

vibration isolator structure buildings with fail-safe system. Part I. Proposal of

mechanism. Nippon Kenchiku Gakkai Taikai, pp. 843-844.

158. Matsumoto, Nobuhiro; Masato Takabayashi; Atsuhiko Yasaka; Masao lizuka

and Hiroaki Kasai. 1986. Studies about application of vibration isolator

structure in FBR plant. Part 1. Experiments with lead rubber support.

Nippon Kenchiku Gakkai Taikai, pp. 983-984.

159. Takenaka, Yasuo; Masato Takabayashi; Kaoru Mizukoshi; Shigeru Yoshigai and

Yoshitaka Sonoda. 1986. Studies about application of vibration isolator

structure in FBR plant. Part 2. Effect of hysteresis damper on floor response.

Nippon Kenchiku Gakkai Taikai, pp. 985-986.

160. Fukushima, Yasuaki; Masato Takabayashi, Kiyotaka Odaka and Manabu Monjo.

1986. Studies about application of vibration isolator structure in FBR plant.

Part 3. Study of the building foundation supported by lead rubber supports.

Nippon Kenchiku Gakkai Taikai, pp. 987-988.

161. Terazaki, Hiroshi; Kentaro Tomura and Hiroshi Kobayashi. 1986. Basic studies

about vibration isolator. Part 1. Analysis of response to seismic waves using

two-degree of freedom system for atomic power room model. Nippon

Kenchiku Gakkai Taikai, pp. 989-990.

162. Kobayashi, Hiroshi; Kentaro Tomura and Hiroshi Terazaki. 1986. Basic studies

about vibration isolator. Part 2. Multi-mass system. Nippon Kenchiku

Gakkai Taikai, pp. 991-992.

163. Kondo, Ippei; Satsuya Soda and Satoshi Watanabe. 1986. Theoretical studies

about the vibration response in a multistoried building equipped with

damping mechanism between flexible and stiff portions. Dai 7 Kai Nippon

Tishin Kogaku Symposium, pp. 1579-1584.

164. Akio, Hayashi. 1986. Calculations and discussions for applications of vibration

isolators in civil structures. Dai 7 Kai Nippon Tishin Kogaku Symposium, pp.

1585-1590.

165. Aoyagi, Sakae; Taiji Matsuda; Osamu Harada; Hirokazu Tanaka; Mikio

Takeuchi and Yoshio Masuko. 1986. Experimental studies for demonstrating

the reliability of a vibration isolator structure. Dai 7 Kai Nippon Tishin

Kogaku Symposium, pp. 1591-1596.

-128-
166. Takayama, Mineo; Akira Sakai; Akira Wada and Hideyuki Tada. 1986.

Experiments on vibration isolator structure. Part 1. Vibration experiments

and observation of earthquake. Dai 7 Kai Nippon Tishin Kogaku Symposium,

pp. 1597-1602. . .

167. Wada, Akira; Kazuhiro Yamamoto; Mineo Takayama and Hideyuki Tada.

1986. Experiments on vibration isolator structure. Part 2. Dynamic analysis

assuming three-directional seismic movement. Dai 7 Kai Nippon Tishin

Kogaku Symposium, pp. 1603-1608.

168. Kawamata, Shigeya; Yoshihiro Abe; Masaaki Onuma and Kenji Mori. 1986.

Controlling the response of a structure to earthquake using inertia pump

damper. Dai 7 Kai Nippon Tishin Kogaku Symposium, pp. 1609-1615.

169. Kondo, Hirofumi; Shigeru Fujimoto; Noboru Narikawa and Yukio Sasaki.

1986. Studies about vibration isolator floor. Dai 7 Kai Nippon Tishin Kogaku

Symposium, pp. 1615-1620.

170. Ohori, Michihiro; Yabana Shuichi; Masayoshi Notake and Yutaka Osawa. 1986.

Studies about system identification of vibration isolator structure. Dai 7 Kai

Nippon Tishin Kogaku Symposium, pp. 1621-1626.

171. Arakawa, Toshiharu; Hirokazu Shimoda; Haruo Shimosaka; Junichiro Omata

and Tadanori Koo. 1986. Base isolation as seen from the vibration

characteristics and seismic response properties. Dai 7 Kai Nippon Tishin

Kogaku Symposium, pp, 1627-1632.

172. Koshida, Hiroshi; Atsuhiko Yasaka; Tetsuo Tanino; Masao lizuka; Nobuo

Fujimoto and Satoshi Ando. 1986. Experiment to ascertain vibration

properties of vibration-proof buildings using vibration isolators. Dai 7 Kai

Nippon Tishin Kogaku Symposium, pp. 1633-1638.

173. Fujita, Satoshi; Takanori Fujita; Tsuneo Sasaki; Shigeru Fujimoto; Noboru

Narikaw^a and Chiaki Tsuruya. 1986. Study on energy absorbing devices

suitable for earthquake isolation of industrial facilities. Dai 7 Kai Nippon

Tishin Kogaku Symposium, pp. 1639-1644.

174. Kaizu, Nobuhiro; Jun'ichi Horiguchi and Junji Mashiba. 1986. Development

of vibration isolator for transformer. Dai 7 Kai Nippon Tishin Kogaku

Symposium, pp. 1645-1650.

175. Sonoda, Yoshitaka; Hiroaki Kasai; Masato Takabayashi and Kaoru Mizukoshi.

1986. Study about introducing vibration isolator structure for high-speed

reactor. (Part 1) . Research plan and analysis of a building equipped with

vibration isolator structure. Dai 7 Kai Tishin Kogaku Svmposium, pp. 1651-

1656.

-129-
176. Kurihara, Masaki; Hiroaki Kasai; Atsuhiko Yasaka and Yoshitaka Sonoda. 1986.

Study about introducing vibration isolator structure for high-speed reactor. Part 2. Small model experiments with rubber lamiantes and friction damper.

Dai 7 Kai Nippon Tishin Kogaku Symposium, pp. 1657-1662.

177. lizuka, Masao; Masato Takabayashi; Atsuhiko Yasaka and Masaki Kurihara.

1986. Study about introducing vibration isolator structure for high-speed

reactor. Part 3. Dynamic properties of lead rubber support. Dai 7 Kai Nippon

Tishin Kogaku Symposium, pp. 1663-1668.

178. Fujita, Takafumi; Naoki Inoue; Kin'ichiro Asami, Akira Tsuruta and Shoji

Takeshita. 1986. Development of three-dimensional vibration isolated,

vibration-resistant floor using multilayered rubber. Dai 7 Kai Nippon Tishin

Kogaku Symposium, pp. 1669-1674.

179. Kamagata, Shuichi; Takuji Kobori and Hiroo Kanayama. 1986. Studies about

seismic response-control structure advocating DIB systems. Dai 7 Kai Nippon

Tishin Kogaku Symposium, pp. 1723-1728.

-130-
NIST-114A

(REV. 3-90) U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

BIBLIOGRAPHIC DATA SHEET

1. PUBUCATION OR REPORT NUMBER

NIST/SP-832, Vol. 1

2. PERFORMING ORGANIZATION REPORT NUMBER

3. PUBUCATION DATE April 1992

4. TITLE AND SUBTITLE

Earthquake Protection in Buildings through Base Isolation

5. AUTHOR(S)

Building Center of Japan (MOC) (Noel J. Raufaste, Editor)

6. PERFORMING ORGANIZATION (IF JOINT OR OTHER THAN NIST, SEE INSTRUCTIONS)

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

QAITHERSBURG, MD 20899

7. CONTRACT/GRANT NUMBER

8. TYPE OF REPORT AND PERIOD COVERED

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (STREET, CITY, STATE, ZIP)

10. SUPPLEMENTARY NOTES

11. ABSTRACT (A 200-WORD OR LESS FACTUAL SUMMARY OF MOST SIGNIFICANT INFORMATION. IF DOCUMENT INCLUDES A SIGNIFICANT BIBUOGRAPHY OR

UTERATURE SURVEY, MENTION IT HERE.)

This is Volume l of a two volume series on energy dissipating systems for buildings and

other structures. This volume, Earthquake Protection in Buildings through Base Isolation

describes energy dissipating systems and reviews their applications and effectiveness. The

documents include guidelines for evaluating energy dissipating systems and a directory of the

systems used in buildings and other structures. The two volume reports were produced by

the Building Center of Japan under sponsorship of the Japanese Ministry of Construction

(MOC) to describe the state-of-art of energy dissipating systems and to review their use in

mitigating damages from earthquakes. The subjects addressed in these reports include: the

history and types of passive energy dissipators; their applications, evaluations, and

performance; and case histories of these systems exposed to seismic loading.

12. KEY WORDS (6 TO 12 ENTRIES; ALPHABETICAL ORDER; CAPITAUZE ONLY PROPER NAMES; AND SEPARATE KEY WORDS BY SEMICOLONS)

active damper; base isolation; damping; devices; evaluation; passive damper; performance;

seismic; structures; wind loads

13. AVAILABIUTY UNUMITED

FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE TO NATIONAL TECHNICAL INFORMATION SERVICE (NTIS). X

X

X

ORDER FROM SUPERINTENDENT OF DOCUMENTS, U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON, DC 20402. ORDER FROM NATIONAL TECHNICAL INFORMATION SERVICE (NTIS), SPRINGFIELD, VA 22161.

14. NUMBER OF PRINTED PAGES

161

15. PRICE

ELECTRONIC FORM * u.5. G. P. 0. : 1992-311-891 :60464

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