Seismic Isolation for Designers and Structural Engineers

387 Pages·2011·12.242 MB·English

by  R Ivan Skinner, William H Robinson, Trevor E Kelly

Seismic Isolation

Designers
for

Structural Engineers
and

R. Ivan Skinner
Trevor E. Kelly
Bill (W.H.) Robinson
Seismic Isolation

Designers
for

Structural Engineers
and

R. Ivan Skinner

Trevor E. Kelly
Holmes Consulting Group
www.holmesgroup.com

Bill (W.H.) Robinson
Robinson Seismic Ltd
www.rslnz.com
CONTENTS

Preface (i)

Acknowledgements (iii)

Author Biographies (iv)

Frequently Used Symbols And Abbreviations (v)

CHAPTER 1: INTRODUCTION.........................................................................................................1

1.1 Seismic Isolation in Context...........................................................................................................................1
1.2 Flexibility, Damping and Period Shift...........................................................................................................3
1.3 Comparison of Conventional & Seismic Isolation Approaches.............................................................5
1.4 Components in an Isolation System............................................................................................................6
1.5 Practical Application of the Seismic Isolation Concept..........................................................................7
1.6 Topics Covered in this Book..........................................................................................................................9

CHAPTER 2: GENERAL FEATURES OF STRUCTURES WITH SEISMIC ISOLATION.............................11

2.1 Introduction.....................................................................................................................................................11
2.2 Role of Earthquake Response Spectra and Vibrational Modes in the Performance
of Isolated Structures......................................................................................................................................11
2.2.1 Earthquake Response Spectra...................................................................................................11
2.2.2 General Effects of Isolation of the Seismic Responses of Structures....................................15
2.2.3 Parameters of Linear and Bilinear Isolation Systems...............................................................16
2.2.4 Calculation of Seismic Responses..............................................................................................20
2.2.5 Contributions of Higher Modes to the Seismic Responses of Isolated Structures...............21
2.3 Natural Periods and Mode Shapes of Linear Structures – Unisolated and Isolated............................22
2.3.1 Introduction....................................................................................................................................22
2.3.2 Structural Model and Controlling Equations............................................................................22
2.3.3 Natural Periods and Mode Shapes............................................................................................24
2.3.4 Example – Modal Periods and Shapes......................................................................................25
2.3.5 Natural Periods and Mode Shapes with Bilinear Isolation......................................................26
2.4 Modal and Total Seismic Responses...........................................................................................................27
2.4.1 Seismic Responses Important for Seismic Design.....................................................................27
2.4.2 Modal Seismic Responses............................................................................................................28
2.4.3 Structural Responses for Modal Responses...............................................................................30
2.4.4 Example – Seismic Displacements and Forces........................................................................30
2.4.5 Seismic Responses with Bilinear Isolators...................................................................................31
2.5 Comparisons of Seismic Responses of Linear and Bilinear Location Systems......................................34
2.5.1 Comparative Study of Seven Cases..........................................................................................34
2.6 Guide to Assist the Selection of Isolation Systems.....................................................................................38

CHAPTER 3: ISOLATOR DEVICES AND SYSTEMS...........................................................................43

3.1 Isolator Components and Isolator Parameters..........................................................................................43
3.1.1 Introduction....................................................................................................................................43
3.1.2 Combination of Isolator Components to Form Different Isolation Systems........................43
3.2 Plasticity of Metals..........................................................................................................................................46
3.3 Steel Hysteretic Dampers..............................................................................................................................49
3.3.1 Introduction....................................................................................................................................49
3.3.2 Types of Steel Damper.................................................................................................................51
3.3.3 Approximate Force-Displacement Loops for Steel-Beam Dampers....................................52
3.3.4 Bilinear Approximation to Force-Displacement Loops...........................................................55
3.3.5 Fatigue Life of Steel-Beam Dampers.........................................................................................57
3.3.6 Summary of Steel Dampers.........................................................................................................59
3.4 Lead Extrusion Dampers................................................................................................................................59
3.4.1 General...........................................................................................................................................59
3.4.2 Properties of the Extrusion Damper............................................................................................62
3.4.3 Summary and Discussion of Lead Extrusion Dampers.............................................................65
3.5 Laminated-Rubber Bearings for Seismic Isolators......................................................................................66
3.5.1 Rubber Bearings for Bridges and Isolators.................................................................................66
3.5.2 Rubber Bearing, Weight Capacity Wmax...................................................................................67
3.5.3 Rubber Bearing Isolation: Stiffness, Period and Damping.....................................................68
3.5.4 Allowable Seismic Displacement Xb..........................................................................................70
3.5.5 Allowable Maximum Rubber Strains..........................................................................................72
3.5.6 Other Factors in Rubber Bearing Design...................................................................................74
3.5.7 Summary of Laminated Rubber Bearings.................................................................................74
3.6 Lead Rubber Bearings....................................................................................................................................74
3.6.1 Introduction....................................................................................................................................74
3.6.2 Properties of the Lead Rubber Bearing.....................................................................................77
3.7 Further Isolator Components and Systems.................................................................................................83
3.7.1 Isolator Damping Proportional to Velocity...............................................................................83
3.7.2 PTFE Sliding Bearings.....................................................................................................................84
3.7.3 PTFE Bearings Mounted on Rubber Bearings............................................................................85
3.7.4 Tall Slender Structures Rocking with Uplift.................................................................................85
3.7.5 Further Components for Isolator Flexibility................................................................................86
3.7.6 Buffers to Reduce the Maximum Isolator Displacement........................................................87
3.7.7 Active Isolation Systems...............................................................................................................88

CHAPTER 4: ENGINEERING PROPERTIES OF ISOLATORS..............................................................89

4.1 Sources of Information...................................................................................................................................89
4.2 Engineering Properties of Lead Rubber Bearings......................................................................................89
4.2.1 Shear Modulus...............................................................................................................................90
4.2.2 Rubber Damping...........................................................................................................................90
4.2.3 Cyclic Change in Properties.......................................................................................................91
4.2.4 Age Change in Properties...........................................................................................................93
4.2.5 Design Compressive Stress...........................................................................................................94
4.2.6 Design Tension Stress.....................................................................................................................94
4.2.7 Maximum Shear Strain..................................................................................................................95
4.2.8 Bond Strength................................................................................................................................97
4.2.9 Vertical Deflections.......................................................................................................................97
4.3 Engineering Properties of High Damping Rubber Isolators......................................................................100
4.3.1 Shear Modulus...............................................................................................................................100
4.3.2 Damping.........................................................................................................................................101
4.3.3 Cyclic Change in Properties.......................................................................................................102
4.3.4 Age Change in Properties...........................................................................................................103
4.3.5 Design Compressive Stress...........................................................................................................103
4.3.6 Maximum Shear Strain..................................................................................................................103
4.3.7 Bond Strength................................................................................................................................103
4.3.8 Vertical Deflections.......................................................................................................................103
4.3.9 Wind Displacements.....................................................................................................................104
4.4 Engineering Properties of Sliding Type Isolators.........................................................................................104
4.4.1 Dynamic Friction Coefficient......................................................................................................105
4.4.2 Static Friction Coefficient.............................................................................................................106
4.4.3 Effect of Static Friction on Performance...................................................................................108
4.4.4 Check on Restoring Force...........................................................................................................110
4.4.5 Age Change in Properties...........................................................................................................110
4.4.6 Cyclic Change in Properties.......................................................................................................111
4.4.7 Design Compressive Stress...........................................................................................................111
4.4.8 Ultimate Compressive Stress........................................................................................................111
4.5 Design Life of Isolators....................................................................................................................................111
4.6 Fire Resistance.................................................................................................................................................111
4.7 Effects of Temperature on Performance....................................................................................................112
4.8 Temperature Range for Installation.............................................................................................................112

CHAPTER 5: ISOLATION SYSTEM DESIGN.....................................................................................113

5.1 Introduction.....................................................................................................................................................113
5.1.1 Assessing Suitability........................................................................................................................113
5.1.2 Design Development for an Isolation Project..........................................................................115
5.2 Design Equations for Elastomeric Bearing Types.......................................................................................116
5.2.1 Codes..............................................................................................................................................116
5.2.2 Empirical Data...............................................................................................................................116
5.2.3 Definitions........................................................................................................................................116
5.2.4 Range of Rubber Properties........................................................................................................117
5.2.5 Vertical Stiffness and Load Capacity........................................................................................118
5.2.6 Vertical Stiffness.............................................................................................................................118
5.2.7 Compressive Rated Load Capacity..........................................................................................119
5.2.8 AASHTO 1999 Requirements........................................................................................................120
5.2.9 Tensile Rated Load Capacity......................................................................................................121
5.2.10 Bucking Load Capacity...............................................................................................................121
5.2.11 Lateral Stiffness and Hysteresis Parameters for Bearing..........................................................122
5.2.12 Lead Core Confinement..............................................................................................................125
5.3 Basis of an Isolation System Design Procedure..........................................................................................126
5.3.1 Elastomeric Based Systems..........................................................................................................127
5.3.2 Sliding and Pendulum Systems....................................................................................................127
5.3.3 Other Systems.................................................................................................................................127
5.4 Step-By-Step Implementation of a Design Procedure.............................................................................127
5.4.1 Example of Illustrate Calculations..............................................................................................128
5.4.2 Design Code..................................................................................................................................129
5.4.3 Units..................................................................................................................................................129
5.4.4 Seismic and Building Definition...................................................................................................130
5.4.5 Material Definition.........................................................................................................................131
5.4.6 Isolator Types and Load Data.....................................................................................................133
5.4.7 Isolator Dimensions........................................................................................................................134
5.4.8 Calculate Bearing Properties......................................................................................................136
5.4.9 Gravity Load Capacity................................................................................................................138
5.4.10 Calculate Seismic Performance.................................................................................................139
5.4.11 Seismic Load Capacity................................................................................................................143
5.4.12 Assess Factors of Safety and Performance..............................................................................144
5.4.13 Properties for Analysis...................................................................................................................146
5.4.14 Hysteresis Properties......................................................................................................................147

CHAPTER 6: EFFECT OF ISOLATION ON BUILDINGS.....................................................................149

6.1 Prototype Buildings.........................................................................................................................................149
6.1.1 Building Configuration..................................................................................................................149
6.1.2 Design of Isolators..........................................................................................................................150
6.1.3 Evaluation Procedure...................................................................................................................156
6.1.4 Comparison with Design Procedure..........................................................................................158
6.1.5 Isolation System Performance.....................................................................................................164
6.1.6 Building Inertia Loads....................................................................................................................166
6.1.7 Floor Accelerations.......................................................................................................................175
6.1.8 Optimum Isolation Systems..........................................................................................................180
6.2 Example Assessment of Isolator Properties.................................................................................................182

CHAPTER 7: SEISMIC ISOLATION OF BUILDINGS AND BRIDGES..................................................185

7.1 Introduction to Isolation of Buildings............................................................................................................185
7.2 Scope of Building Example...........................................................................................................................185
7.3 Seismic Input....................................................................................................................................................186
7.4 Design of Isolation System.............................................................................................................................187
7.5 Analysis Models...............................................................................................................................................189
7.6 Analysis Results................................................................................................................................................191
7.6.1 Summary of Results.......................................................................................................................195
7.7 Test Conditions................................................................................................................................................195
7.8 Production Test Results...................................................................................................................................196
7.9 Summary ..........................................................................................................................................................197
7.10 Implementation in Spreadsheet..................................................................................................................198
7.10.1 Material Definition.........................................................................................................................198
7.10.2 Project Definition...........................................................................................................................199
7.10.3 Isolator Types and Load Data.....................................................................................................200
7.10.4 Isolator Dimensions........................................................................................................................201
7.10.5 Isolator Performance....................................................................................................................203
7.10.6 Properties for Analysis...................................................................................................................205
7.11 Introduction to Isolation for Bridges.............................................................................................................207
7.12 Seismic Separation of Bridges.......................................................................................................................208
7.13 Design Specifications for Bridges.................................................................................................................209
7.13.1 The 1991 AASHTO Guide Specifications....................................................................................209
7.13.2 The 1999 AASHTO Guide Specifications....................................................................................210
7.14 Use of Bridge Specifications for Building Isolator Design.........................................................................210
7.15 Design of Isolation Systems............................................................................................................................212
7.15.1 Non-Seismic Loads........................................................................................................................212
7.15.2 Effect of Bent Flexibility.................................................................................................................213
7.16 Analysis of Isolated Bridges...........................................................................................................................215
7.17 Design Procedure for Bridge Isolation.........................................................................................................216
7.17.1 Example Bridge..............................................................................................................................216
7.17.2 Design of Isolators..........................................................................................................................218
7.17.3 Accounting for Bent Flexibility in Design...................................................................................220
7.17.4 Evaluation of Performance.........................................................................................................224
7.17.5 Effect of Isolation System on Displacements............................................................................228
7.17.6 Effect of Isolation on Forces........................................................................................................229
7.17.7 Summary.........................................................................................................................................231
7.18 Implementation in Spreadsheet..................................................................................................................231
7.18.1 Material Properties........................................................................................................................232
7.18.2 Dimensional Properties.................................................................................................................232
7.18.3 Load and Design Data.................................................................................................................233
7.18.4 Isolation Solution............................................................................................................................234

CHAPTER 8: APPLICATIONS OF SEISMIC ISOLATION...................................................................237

8.1 Introduction.....................................................................................................................................................237
8.2 Structures Isolated in New Zealand.............................................................................................................239
8.2.1 Introduction....................................................................................................................................239
8.2.2 Road Bridges..................................................................................................................................242
8.2.3 South Rangitikei Viaduct with Stepping Isolation....................................................................244
8.2.4 William Clayton Building...............................................................................................................245
8.2.5 Union House...................................................................................................................................247
8.2.6 Wellington Central Police Station...............................................................................................249
8.3 Structures Isolated in Japan..........................................................................................................................251
8.3.1 Introduction....................................................................................................................................251
8.3.2 The C-1 Building, Cuchu City, Tokyo..........................................................................................255
8.3.3 The High-Tech R&D Centre, Obayashi Corporation...............................................................255
8.3.4 Comparison of Three Buildings with Different Seismic Isolation Systems.............................256
8.3.5 Oiles Technical Centre Building..................................................................................................258
8.3.6 Miyagawa Bridge..........................................................................................................................259
8.4 Structures Isolated in the USA.......................................................................................................................261
8.4.1 Introduction....................................................................................................................................261
8.4.2 Foothill Communities Law and Justice Centre, San Bernandino, California......................263
8.4.3 Salt Lake City and Country Building: Retrofit...........................................................................264
8.4.4 USC University Hospital, Los Angeles..........................................................................................265
8.4.5 Sierra Point Overhead Bridge, San Francisco...........................................................................266
8.4.6 Sexton Creek Bridge, Illinois.........................................................................................................267
8.5 Structures Isolated in Italy..............................................................................................................................268
8.5.1 Introduction....................................................................................................................................268
8.5.2 Seismically Isolated Bridges.........................................................................................................268
8.5.3 The Mortaiolo Bridge.....................................................................................................................269
8.6 Isolation of Delicate or Potentially Hazardous Structures or Substructures...........................................274
8.6.1 Introduction....................................................................................................................................274
8.6.2 Seismically Isolated Nuclear Power Stations.............................................................................275
8.6.3 Protection of Capacity Banks, Haywards, New Zealand.......................................................275
8.6.4 Seismic Isolation of a Printing Press in Wellington, New Zealand..........................................277

CHAPTER 9: IMPLEMENTATION ISSUES..........................................................................................279

9.1 Introduction.....................................................................................................................................................279
9.2 Isolator Locations and Types.........................................................................................................................279
9.2.1 Selection of Isolation Plane.........................................................................................................279
9.2.2 Selection of Device Type.............................................................................................................283
9.3 Seismic Input....................................................................................................................................................292
9.3.1 Form of Seismic Input....................................................................................................................292
9.3.2 Recorded Earthquake Motions...................................................................................................293
9.3.3 Near Fault Effects..........................................................................................................................300
9.3.4 Variations in Displacements........................................................................................................300
9.3.5 Time History Seismic Input............................................................................................................302
9.3.6 Selecting and Scaling Records for Time History Analysis........................................................302
9.3.7 Selecting Records from a Set......................................................................................................303
9.3.8 Comparison of Earthquake Scaling Factors.............................................................................304
9.4 Detailed System Analysis...............................................................................................................................306
9.4.1 Single Degree-of-Freedom Model.............................................................................................307
9.4.2 Two Dimensional Non-Linear Model..........................................................................................307
9.4.3 Three Dimensional Equivalent Linear Model............................................................................307
9.4.4 Three Dimensional Model-Elastic Superstructure, Yielding Isolators.....................................308
9.4.5 Fully Non-Linear Three Dimensional Model...............................................................................308
9.4.6 Device Modeling...........................................................................................................................308
9.4.7 ETABS Analysis for Buildings..........................................................................................................309
9.4.8 Concurrency Effects.....................................................................................................................313
9.5 Connection Design........................................................................................................................................316
9.5.1 Elastomeric Based Isolators..........................................................................................................316
9.5.2 Sliding Isolators...............................................................................................................................321
9.5.3 Installation Examples.....................................................................................................................322
9.6 Structural Design
9.6.1 Design Concepts...........................................................................................................................327
9.6.2 UBC Requirements........................................................................................................................328
9.6.3 MCE Level of Earthquake............................................................................................................332
9.6.4 Non-Structural Components.......................................................................................................332
9.6.5 Bridges.............................................................................................................................................333
9.7 Specifications..................................................................................................................................................333
9.7.1 General...........................................................................................................................................333
9.7.2 Testing..............................................................................................................................................335

CHAPTER 10: FEASIBILITY ASSESSMENT, EVALUATION AND FURTHER DEVELOPMENT
OF SEISMIC ISOLATION............................................................................................337

10.1 Decision-Making in a Seismic Isolation Context........................................................................................337
10.1.1 Seismic Isolation Decisions to be Made....................................................................................337
10.1.2 Seismic Isolation Decisions in the Wellington Area..................................................................338
10.2 Construction Projects in New Zealand and India 1992 to 2005..............................................................339
10.2.1 Introduction....................................................................................................................................339
10.2.2 Retrofits............................................................................................................................................339
10.2.3 Te Papa Tongarewa.....................................................................................................................339
10.2.4 Other Seismically Isolated Buildings...........................................................................................341
10.2.5 Bhuj Hospital...................................................................................................................................341
10.3 A Feasibility Study for Seismic Isolation........................................................................................................343
10.3.1 Te Papa Tongarewa, the Museum of New Zealand...............................................................343
10.3.2 Description......................................................................................................................................343
10.3.3 Seismic Design Criteria.................................................................................................................344
10.3.4 Feasibility Study..............................................................................................................................345
10.3.5 Isolation System Design................................................................................................................346
10.3.6 Evaluation of Structural Performance.......................................................................................346
10.3.7 Results of ANSR-II Analysis.............................................................................................................348
10.3.8 Conclusions....................................................................................................................................348
10.4 Performance in Real Earthquakes...............................................................................................................350
10.5 New Approaches to Seismic Isolation.........................................................................................................353
10.5.1 Introduction....................................................................................................................................353
10.5.2 The RoBall........................................................................................................................................353
10.5.3 The RoGlider...................................................................................................................................356
10.6 Project Management Approach.................................................................................................................358
10.7 Future................................................................................................................................................................359

Reference List………………………………………………………………………………………………………361

Additional Resources…………………………………………………………………………………………….367
PREFACE

This is a revised version of the book “An Introduction to Seismic Isolation” published by Wiley and
Sons in 1993. There have been many changes in the course of this revision and this is reflected in
the changed title - “Seismic Isolation for Designers and Structural Engineers”.

This new book builds on the previous one and uses much of the previous material, but it has
different authorship and more focus on practical applications. It acknowledges the pioneering
work that has been done over the past 30 to 40 years but aims to present seismic isolation in a
different way, as an established technique that could be considered widely, even routinely, as
an option by designers and structural engineers. Trevor Kelly’s input as a practising structural
engineer has transformed the book into a modern version that makes full use of computer
science techniques. (A CD Rom is included).

The original book was authored by R I Skinner, W H Robinson and GH McVerry, who were at the
time working at the Department of Scientific and Industrial Research (DSIR) in Wellington, New
Zealand. The book recorded the innovative earthquake engineering research that had been
carried out at the DSIR over the previous 25 years (see Chapter 3 of both books, and Chapter 8
of this book, which is carried over from the previous Chapter 6). However the book also marked
the end of an era, as it was written at a time when change was in the air and the DSIR was
about to be disestablished.

The DSIR was closed down mid-1992 as part of a New-Zealand wide drive to making science
more commercial. Bill Robinson has risen to this challenge by forming Robinson Seismic Limited
(RSL), an engineering company specialising in applications of seismic isolation to protect
structures from earthquake damage. Bill has continued as one of the authors of this new book.
The new author is Trevor Kelly, a structural engineer with Holmes Consulting, which has been
involved in the design and supply of seismic isolation systems for almost 20 years. Trevor’s
interest is in the structural engineering aspects of applying seismic isolation/damping and the
new chapters that he has written emphasise the engineering aspects.

The new book therefore retains the mathematical tools in Chapters 1, 2 and 3 of “An
Introduction to Seismic Isolation” but replaces the empirical methods of succeeding chapters
with detailed design and documentation material of the type that a structural engineer would
need to implement isolation. This is followed through with examples of practical designs.

This book provides both theory and design aspects of seismic isolation. This will be useful for
structural engineers and teachers of engineering courses. For other structural components
(concrete frames, steel braces etc) the engineering student is taught the theory (lateral loads,
bending moments) but then also the design (how to select sizes, detail reinforcing, bolts). This
book will do the same for seismic engineering.

The book provides practical examples of computer applications as well as device design
examples so that the structural engineer is able to do a preliminary design that won’t specify
impossible constraints. The book also addresses the steps that need to be taken to ensure the
design is code compliant.

The structural engineer is the key to adoption of seismic isolation technology. The book aims to
provide enough design information so that the structural engineer can be confident on
implementing seismic isolation; otherwise he/she won’t want to take the risk even if the architect
or owner is enthusiastic. Firms like RSL and Holmes Consulting will continue to be available to
provide expert advice and the benefits of their considerable experience in the field of device
design and seismic isolation.
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The engineering credentials and expertise of Bill Robinson and his company, RSL, are evident
from Chapters 3 and 8 (which describe the invention and development of the Lead Rubber
Bearing). Bill Robinson has been honoured world wide for this work and has received recognition
in New Zealand from the scientific community and the business community. There has also been
considerable interest in the public domain, in the display of seismic isolation in Te Papa
Tongarewa, the Museum of New Zealand on the waterfront in Wellington, which was built on
Lead Rubber Bearings (see Chapter 9).

The engineering credentials of Trevor Kelly are evident from his work as Technical Director of
Holmes Consulting Group (HCG), part of the Holmes Group, which is New Zealand's largest
specialist structural engineering company, with over 90 staff in three main offices in New
Zealand plus 25 in the San Francisco office. Trevor heads the seismic isolation division of HCG
in the Auckland office. He has over 15 years experience in the design and evaluation of
seismic isolation systems in the United States, New Zealand and other countries and is a
licensed Structural Engineer in California.

Since 1954 the company has designed a wide range of structures in the commercial and
industrial fields. HCG has been progressive in applications of seismic isolation and since its first
isolated project, Union House, in 1982, has completed six isolated structures. On these
projects HCG provided full structural engineering services. In addition, for over 8 years HCG
provided design and analysis services to Skellerup Industries of New Zealand and later
Skellerup Oiles Seismic Protection (SOSP), a San Diego based manufacturer of seismic
isolation hardware. Isolation hardware used on their projects included Lead Rubber Bearings
(LRBs), High Damping Rubber Bearings (HDR), Teflon on stainless steel sliding bearings, sleeved
piles and steel cantilever energy dissipators.

The company has developed design and analysis software to ensure effective and
economical implementation of seismic isolation for buildings, bridges and industrial
equipment. Expertise encompasses the areas of isolation system design, analysis,
specifications and evaluation of performance. In writing Chapters 4, 5, 6 and 7 of this book
Trevor has drawn on his practical experience in the field and explains methods of calculating
seismic responses using state-of-the-art computer software such as ETABS, used for the linear
and nonlinear analysis of buildings.

This book is the product of three expert engineers who have, over a long period of years,
worked separately and collaboratively to design and develop earthquake isolation solutions
and to incorporate them into existing and new structures. Collaboration on this book is a
further joint venture and has a two-fold aim — to be used for the benefit of professionals
looking to apply earthquake isolation techniques, and to be used in educating a new
generation of structural engineers and designers.
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ACKNOWLEDGEMENTS

In presenting this new book, which builds on and revises the previous book “An Introduction to
Seismic Isolation”, thanks are due to all those who made the previous book possible, especially
Graeme McVerry, as well as those who have been involved in its revision. Thanks to Barbara
Bibby who again provided editing services, to Heather Naik and the staff and shareholders of
Robinson Seismic Ltd and Holmes Consulting Group, to the Book Committees at RSL and Holmes
Consulting who have reviewed it, and to FORST for providing funding for its production.

Trevor Kelly
Holmes Consulting Group
34 Waimarei Avenue
Paeroa
NEW ZEALAND
www.holmesgroup.com

Bill Robinson
Robinson Seismic Ltd
P O Box 33093
Petone
NEW ZEALAND
www.rslnz.com

Ivan Skinner
31 Blue Mountains Road
Silverstream
Wellington
New Zealand

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