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SEISMIC DESIGN FOR ARCHITECTS

OU TW ITTING THE QUAKE

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SEISMIC DESIGN FOR

ARCHITECTS

OUTWITTING THE QUAKE

Andrew Charleson

AMSTERDAM • BOSTON • HEIDELBERG • LONDON

NEW YORK • OXFORD • PARIS • SAN DIEGO

SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO

Architectural Press is an imprint of Elsevier

Architectural Press is an imprint of Elsevier

Linacre House, Jordan Hill, Oxford OX2 8DP, UK

30 Corporate Drive, Suite 400, Burlington, MA 01803, USA

First edition 2008

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No responsibility is assumed by the publisher for any injury and/or damage to persons

or property as a matter of products liability, negligence or otherwise, or from any use

or operation of any methods, products, instructions or ideas contained in the material

herein.

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

Library of Congress Cataloguing in Publication Data

A catalogue record for this book is available from the Library of Congress

ISBN: 978-0-7506-8550-4

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Typeset by Charon Tec Ltd., A Macmillan Company. (www.macmillansolutions.com)

Printed and bound in Hungary

08 09 10 11 12 10 9 8 7 6 5 4 3 2 1

CONTENTS

Foreword by Christopher Arnold, FAIA, RIBA ix

Preface xi

Acknowledgements xiii

1 Earthquakes and ground shaking 1

Introduction 1

Understanding earthquakes 4

Earthquake magnitude and intensity 9

The nature of earthquake shaking11

Importance of ground conditions13

References and notes14

2 How buildings resist earthquakes 15

Introduction15

Nature of seismic forces15

Factors affecting the severity of seismic forces18

Resisting seismic forces25

Torsion27

Force paths29

Notes 32

3 Seismic design approaches33

Introduction33

Historical overview33

Current seismic design philosophy38

References and notes47

4 Horizontal structure49

Introduction49

Diaphragms50

Transfer diaphragms56

Bond beams58

Collectors and ties61

Note 61

5 Vertical structure 63

Introduction63

Shear walls66

Braced frames76

Moment frames81

Mixed systems89

References91

6 Seismic design and architecture93

Introduction93

Integrating seismic resisting structure and architecture94

How much structure is needed?99

Special structures102

Contemporary architecture in seismic regions104

Case study: the Villa Savoye108

References and notes112

7 Foundations113

Introduction113

Seismic foundation problems and solutions114

Foundation types119

Foundation investigations119

Retaining structures121

References and notes123

8 Horizontal configuration125

Introduction125

Torsion128

Re-entrant corners132

Diaphragm discontinuities134

Non-parallel systems136

Pounding and separation137

Bridging between buildings140

References and notes141

9 Vertical configuration143

Introduction143

Soft storeys144

Short columns148

Discontinuous and off-set walls151

Setbacks 154

vi CONTENTS

Buildings on sloping sites155

References and notes155

10 Non-structural elements: those likely to cause

structural damage 157

Introduction157

Infill walls159

Staircases168

References171

11 Other non-structural elements 173

Introduction173

Cladding174

Parapets and appendages181

Partition walls182

Suspended ceilings and raised floors182

Mechanical and electrical equipment184

Building contents184

References186

12 Retrofitting187

Introduction187

Why retrofit?189

Retrofit objectives191

Retrofit approaches192

Retrofit techniques195

Non-structural retrofit202

Historic buildings203

References204

13 Professional collaboration and communication207

Introduction207

Client 208

Design team210

Contractor 213

Post-earthquake215

References and notes216

14 New technologies217

Introduction217

Seismic isolation218

CONTENTS vii

Dampers 224

Damage avoidance227

Innovative structural configurations228

Structural design approaches229

Other developments230

References231

15 Urban planning233

Introduction233

Planning 234

Tsunami 237

Fire following earthquake238

Interdisciplinary interaction240

References and notes240

16 Issues in developing countries243

Introduction243

Design 245

Construction 248

Resources248

References249

17 Earthquake architecture251

Introduction251

Expression of seismic resistance253

Expression of structural principles and actions255

Seismic issues generating architecture258

Referencesand notes 262

18 Summary 265

Resources 269

Introduction269

Institutions and organizations269

Publications 272

Index 275

viii CONTENTS

I knew that I would enjoy this book when I saw that Andrew Charleson

had used one of my favorite buildings, the Villa Savoie in Paris, as a

seismic design case study. The earthquake engineers ’ nightmare, with

its pin-like pilotis, ramps and roof garden – the epitome of the free

planned International Style dwelling – it floats above the field in Poissy,

giving the illusion of being on the sea. The author uses his re-design

to demonstrate that, to add seismic resistance as an afterthought to

a completed preliminary design, results in a far from elegant solution

given the incompatibility of the seismic-resisting structure with the

intended interior planning.

This little study is but one example of how he has made material, with

which I am reasonably familiar, seem fresh and intriguing. I also liked his

analogy between finger snapping and the sudden release of energy that

initiates an earthquake.

Another pleasure was that in two hundred and sixty-odd pages he

covers every seismic design issue under the sun with only a passing

mention of seismic codes and only one (I believe) equation FMA.

The seismic codes say nothing about seismic design, which is the act of

conceiving a strategy for the reduction of seismic risk and the struc￾tural/architectural systems that will accomplish it. Reading, or reading

about, building codes and regulations is only one form of slow torture.

The author’s intent (with which I agree) is ambitious. Structure, he

says, is an indispensable architectural element imbued with the possibility of

enhancing architectural functions and qualities, and if structure is to play

architectural roles other than load-bearing, its design cannot be left to

just anybody. An architect, he says, should have the skills to conceive

the structural configuration at the preliminary design stage, which not

only satisfies programmatic requirements and his or her design ideas,

but is structurally sound with respect to seismic forces. This book is

intended to provide the means by which the architect (with consider￾able diligence) can acquire these skills.

Such talk may, of course, upset our engineering friends (although note

that the author is an engineer) and cause grumbling about the engineer￾ing ignorance of architects together with their unreasonable egotisms.

FOREWORD

But the author is talking about preliminary design, the most impor￾tant phase of the design process, in which all the overall configuration,

the interior spaces, exterior skin, general dimensions and materials

are defined. How can this be done properly without, at the same time,

defining the structure? In fact, the author recommends collaboration

between the engineer and architect at the earliest point in the design

process. This will be more effective if the architect has a good knowl￾edge of the structural issues.

Faced with this self-imposed task, Andrew Charleson has, I think, writ￾ten a landmark book in the exposition of complex structural and archi￾tectural concept issues that use lucid prose to describe concepts and

hundreds of diagrams and photographs to illuminate his message. It is

instructive to discover how many sophisticated structural concepts

can be explained in word and illustration to help develop an intui￾tive sense of structural action and reaction. You can find out exactly

why symmetrical plans are good, as well as many ways of circumvent￾ing them if they do not suit your site, program or building image. The

author’s many years of experience teaching architectural students have

enabled him to expand the range and refine the detail of his descrip￾tions, and ensure their intelligibility.

Finally, if the architect still resists the effort to understand the earth￾quake, it must be remembered that we are not talking about an intel￾lectual or aesthetic game, but knowledge and its application that may,

in some future unknown event, save lives, reduce injuries and lessen

economic and social catastrophe. Besides which, the whole subject is

inherently fascinating.

Christopher Arnold

x FOREWORD

This book draws upon my structural engineering experience design￾ing in the southern tip of the Pacific Rim of Fire, followed by twenty

years teaching in a School of Architecture. Seismic design is a signifi￾cant component in my Structures courses. These courses consist of

formal lectures and tutorials, while including informal sessions where

students are helped to develop seismic and gravity structure for their

own architecture studio design projects. One of the most satisfying

aspects of this less informal teaching is when students utilize structure

not only to resist seismic and gravity forces but also to enrich their

architectural design concepts.

The premise underlying this book is that structure is an indispensable

architectural element imbued with the possibility of enhancing archi￾tectural functions and qualities. For example, appropriately designed

structure can articulate entry into a building and celebrate interior cir￾culation. It can create spaces and provide opportunities for aesthetic

delight. So in the first instance, at preliminary design stage, structure

needs to be designed by an architect.

The approach and content of the book is based upon that view of an

architect’s role in seismic design. If structure is to play architectural

roles other than load-bearing, its design cannot be left to someone

else. An architect should have the skills to conceive the structural

configuration at the preliminary design stage that not only satisfies

programmatic requirements and his or her design ideas, but is struc￾turally sound especially with respect to seismic forces. Subsequent to

this conception of structure, and ideally during that preliminary design

process, structural engineering collaboration is indispensable. Ideally

a structural engineer with specialist technical skills – and a sensitiv￾ity towards architectural aspirations – works alongside the architect

to develop and refine the initial structural form. The engineer, design￾ing well beyond the technical abilities of the architect then determines

member sizes and attends to all the other structural details and issues.

Given the ideal situation outlined above, the book focuses on the core

knowledge that architects require to ‘outwit the quake ’. Written for

those designing buildings, its explanations provide the background,

understanding, strategies and approaches to be applied in design.

PREFACE

Seismic principles and concepts rather than code requirements are

emphasized. With a few exceptions, the book recognizes both the

reality of architectural practice and architects ’ preferences by leaving

equations and calculations to structural engineers.

The intended readership is primarily architectural students and archi￾tects – hence the generous number of explanatory diagrams and

images, and the exclusion of civil engineering structures like bridges,

wharfs and dams. However, the conceptual treatment of seismic resist￾ance will also appeal to students of structural engineering and engi￾neers who appreciate a non-mathematical introduction to seismic

design. The qualitative approach herein complements engineers ’ more

calculation-intensive analysis and design methods, and covers the

design of components such as non-structural elements that most engi￾neering texts and codes treat very briefly.

The chapter sequence of the book reflects a general progression in

complexity. The gradual introduction of more complex issues is appro￾priate for architectural, architectural engineering and building science

programmes. For example, the content of Chapters 1 and 2 is suited

to first or second year courses, Chapters 3 to 5 to second or third

years, and Chapters 6 to 11 to third or fourth years. Other chapters,

especially Chapters 13 and 14 can be inserted into the senior years

of a programme. The amount of material from the book that can be

introduced into given courses may depend upon how much time a

school’s curriculum allocates to Structures. The non-mathematical

approach of this book suggests a reappraisal of how Structures might

be taught. If emphasis upon the quantitative treatment of Structures is

reduced in favour of the introduction of a broader range of structural

topics taught qualitatively, then space can be created for more material

on seismic design.

Andrew Charleson

xii PREFACE

I am very grateful for help received during the preparation of this

book. In particular I thank the following:

● Victoria University of Wellington for research and study leave

to begin work on the book and for research grants for diagram

preparation

● Professor Mary Comerio and the Visiting Scholar Program, Institute

of Urban &Regional Development, University of California, Berkeley

● Those individuals and organizations that have provided images and

granted permission for their use (unacknowledged images are by

the author)

● Paul Hillier for photographic assistance

● Christopher Greenfield for drawing the diagrams

● The scientists, structural engineers and architects who each reviewed

a chapter: Warwick Smith, Reagan Potangoroa (two chapters), Les

Megget, David Whittaker, Win Clark, Alistair Cattanach, Brabha

Brabhaharan, Peter Johnstone, Geoff Sidwell, Arthur Park, Peter Smith,

Rob Jury, Guy Cleverley, Trevor Kelly, Bill Robinson, Jim Cousins,

Graeme McIndoe, Geoff Thomas, Jitendra Bothara and Luke Allen.

Randolph Langenbach commented on various sections of the manu￾script, and

● My wife Annette for her support.

Finally, I acknowledge the use of Frank Lloyd Wright’s phrase ‘ out￾witting the quake ’ as the book’s subtitle and in numerous occasions

throughout the text. Following his insightful but ultimately flawed

design of the Imperial Hotel, Tokyo that involved ‘ floating ’the build￾ing on a deep layer of ‘soft mud ’ in combination with a flexible super￾structure, he writes: ‘Why fight the quake? Why not sympathize with it

and outwit it? ’(Wright, F.L., 1977, Frank Lloyd Wright: An Autobiography.

Quartet Books, Horizon Press, New York, p. 238).

ACKNOWLEDGEMENTS

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