bearing-eggert.pdf

H. Eggert, W. Kauschke

Structural Bearings

irnst &Sohn A Wiley

Company

Helmut Eggert, Wolfgang Kauschke

Structural Bearings

irnst &Sohn A Wiley

Company

Dr.-lng. Helmut Eggert Lenzelpfad 32 12353 Berlin Germany Dipl.-lng. Wolfgang Kauschke Starenweg 10 42781 Haan Germany

This book contains 272 figures and 45 tables

Die Deutsche Bibliothek - CIP-Cataloguing-in-Publication-Data A catalogue record for this publication is available from Die Deutsche Bibliothek ISBN 3-433-01238-5

© 2002 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH, Berlin All rights reserved, especially those of translation into other languages. No part of this book shall be reproduced in any form - i.e. by photocopying, microphotography, or any other process - or be rendered or translated into a language useable by machines, especially data processing machines, without the written permission of the publisher. Typesetting: Manuela Treindl, Regensburg Printing: betz-druck GmbH, Darmstadt Binding: Litges & Dopf Buchbinderei GmbH, Heppenheim Printed in Germany

Preface

Organization of this book Like its German edition, this book has nine main chapters. These chapters are broken down in the list of contents into a maximum of five section levels. In the text, some further subdivision is used to improve ease of reading and referencing. The use of a glossary, which provides a brief definition of subject index terms, is not very common in technical books; we have included one in this book in the hope that it will aid readers in their understanding of this special subject. Contents This book should provide sufficient answers to typical questions related to the design and construction of bridges and industrial structures. Topics covered include: - how to support a structure (chapter 2), - which loads are transferred from the structure into the bearing (chapter 3), - what types of bearings are available (chapter 4), and - which technical guidelines must be taken into account (chapter 5).

result in damage if, for example, the necessary support system cannot be realized. Costs incurred by damage to bearings can be very high if complete replacement of the constructions is necessary. Examples from Germany include: -

unsuitable roller bearings, unsuitable top sealing, installation mistakes, and material mistakes (essential elastomeric bearings).

The most frequent bearing damage is corrosion damage. Serious economic damage can also be caused by corrosion in other fields. Chapter 4 contains proposals for construction with low levels of corrosion.

Chapter 6 provides information on the Approvals of the German Institute for Civil Structures (Deutsches Institut für Bautechnik, DIBt).

The word "bearing" has different technical meanings. This book refers to bearings as technical parts that are manufactured in special plants and used in structures as an interface between the substructure and superstructure. It transfers loads in a defined way and allows for motion or displacements. The different types of bearings are characterized by their function as well as their main material (see section 1.2.4). The glossary provides further definitions.

Reports dealing with research and scientific problems related to the subject of bearings are listed in chapter 7.

Centering elements built together with the structure, such as concrete hinges, are not covered in this book.

This book is meant to serve as a tool for the design engineer, architect, or engineer writing specifications, for the designing, calculating, and testing engineer, and for the civil contractor. The design of a structure will usually a priori define - whether intended or not - the support system. Neglect of this connection can later

This book concentrates on bridges, the classic application of the bearing technique. It mainly deals with nondynamic applications but also gives some additional information on dynamic influences (see sections 2.2.5, 2.2.6, and 3.4). February 2002

Helmut Eggert Wolfgang Kauschke

Preliminary remarks

We wish to thank everyone who has helped us produce this book, particularly our wives for their patience and Dr. Günter Hüffmann for his excellent translation. Contributors to this book: Hans-Peter Rieckmann (section 3.3) Günter Hüffmann/Karl-Heinz Reinsch (section 3.4) Armin Gerber/Jochen Wiedemeyer (section 7.3.1) Karl-Heinz Hehn (section 7.3.2) Section 4.5 was revised for this edition by Florian Deischl Chapters 1 to 4, 8, and 9 were translated into English by Günter Hüffmann

Contents

Preface

V

Preliminary remarks

VI

1

Introduction

1

1.1

History

1

1.2 1.2.1 1.2.2 1.2.3 1.2.4

Terms and descriptions Support and bearings as part of the structure Roll-off, sliding, deformation Bearing, hinge, pendulum Bearing definitions

1 1 2 4 5

1.3

Basic guidelines for selecting the support system

5

1.4 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5

Bearing motion General Displacements caused by temperature Displacements caused by prestressing, creep, and shrinkage Displacements in the bearings caused by outer loads Support rotation

6 6 10 10 11 11

1.5

Bearing symbols

12

1.6 1.6.1 1.6.2 1.6.3 1.6.4 1.6.5

Rotational resistance Basic moment Restoring moment and rotation Other dependencies Influence of horizontal forces Influence of the restoring moment on the structure

12 12 14 15 15 17

2

Structure and bearing system

19

2.1

Introduction

19

2.2 2.2.1 2.2.2 2.2.2.1 2.2.2.2 2.2.2.3 2.2.2.4

Bridges Influence of different bridge cross sections Influence of the bridge plan view Single span bridges (orthogonal) Single span skew bridge Two span bridge (orthogonal) Two span skew bridge

20 20 22 22 23 23 24

VIII

Contents

2.2.2.5 2.2.2.6 2.2.3 2.2.3.1 2.2.3.2 2.2.3.3 2.2.3.4 2.2.4 2.2.5 2.2.6 2.2.7

Continuous beams (orthogonal) Continuous beams (curved) Examples of bearing systems Single span bridge (orthogonal) Two span skew bridge Continuous beams (orthogonal) Continuous beams (curved) Subsoil influence Vibration control of buildings Structures in seismic zones From specification to installation of bearings

24 24 27 27 28 28 28 36 37 37 38

3

Structure and bearing loads

41

3.1

From a hinge to a bearing

41

3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.2.7 3.2.8

Bridge analysis Introduction Transfer of vertical loads Transfer of horizontal loads in longitudinal bridge direction Transfer of horizontal loads in lateral bridge direction Loads depending on the type of bearing Bearing motion Stability (protection against sliding, overturning, and uplift) Safety considerations based on bearing properties

42 42 45 46 48 49 49 50 52

3.3 3.3.1 3.3.2 3.3.3 3.3.3.1 3.3.3.2 3.3.3.3 3.3.3.4 3.3.3.5 3.3.3.6 3.3.3.7 3.3.4

Influence of bearings on the stability of constructions General Boundary and special conditions for bearings Buckling lengths of columns General Single columns Straight bridges with columns of differing lengths Straight bridge with only two column types Straight bridges with rocker bearings Curved bridges Elastic restraint, variable bending resistance, and longitudinal force Proof of total system safety

54 54 55 57 57 58 59 61 62 62 63 64

3.4 3.4.1 3.4.1.1 3.4.1.2 3.4.1.2.1 3.4.1.2.2 3.4.1.2.3 3.4.1.2.4 3.4.2 3.4.3 3.4.3.1

Bearings with high vertical flexibility Bearings for vibration control Basics of vibration and structure-borne noise control Elements for vibration isolation Coil spring elements Viscodampers Elastomeric bearings Comparison of coil springs and elastomeric bearings Bearings for protection against settlements/subsidences Elastic support of buildings Introduction

64 64 64 67 67 70 73 74 74 76 76

Contents

IX

3.4.3.2 3.4.3.3 3.4.3.4 3.4.3.5 3.4.3.6 3.4.3.7 3.4.3.8

Vibration control (mechanical vibrations) Structure-borne noise control Selection of elastic bearings for vibration and structure-borne noise control Base isolation of entire buildings Spring support of partial building areas (room-in-room) Seismic base isolation Track-bed isolation

76 78 78 79 81 82 84

4

Bearing types

87

4.1

Basic remarks

87

4.2 4.2.1 4.2.1.1 4.2.1.2 4.2.1.3 4.2.1.4 4.2.2 4.2.3 4.2.3.1 4.2.3.2 4.2.3.3 4.2.3.4 4.2.3.5 4.2.3.6 4.2.3.7 4.2.3.8

General design and dimensioning rules 88 Materials 88 Types of steel for bearing parts 88 Elements for bolt connections according to EC3-1-1 89 Peculiarities of connectors made of stainless steel 90 Welding 92 Sectional data and degrees of freedom 92 Rules for dimensioning 93 Bearing plates 93 Bolt connections 93 Weld connections 94 Pressure in the bearing joints 95 Verification of static equilibrium 97 Practical advice on the transmission of horizontal loads in the bearing joints . . . . 98 Anchoring through stud bolt dowels 100 Corrosion protection 101

4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.3.5 4.3.5.1 4.3.5.2 4.3.5.3

Fixed bearings Introduction Steel point rocker bearings Pot bearings Spherical bearings Fixed deformation bearings General information Journal bearings Pot deformation bearings

101 101 104 109 113 115 115 116 117

4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.4.4.1 4.4.4.2 4.4.5 4.4.5.1 4.4.5.2 4.4.5.3

Sliding bearings Introduction Guidelines Sliding bearing system Dimensioning of the bearing plates Sliding plate and PTFE-housing Design of the PTFE-housing Point rocker sliding bearings Introduction Design and dimensioning Design basics for the PTFE-housing

118 118 120 120 121 121 123 125 125 126 126

X

Contents

4.4.5.4 4.4.5.5 4.4.6 4.4.6.1 4.4.6.2 4.4.6.3 4.4.6.4 4.4.6.5 4.4.7 4.4.7.1 4.4.7.2 4.4.7.3 4.4.7.4 4.4.7.5 4.4.7.6 4.4.8 4.4.8.1 4.4.8.2 4.4.8.3 4.4.8.4 4.4.8.5 4.4.9 4.4.9.1 4.4.9.2 4.4.9.3 4.4.9.4 4.4.9.5

Load eccentricities for the analysis of the stresses in the PTFE sliding surface .. Load eccentricities for the analysis of the upper and lower bearing joints Pot sliding bearings Basics Design and dimensioning Design basics for the PTFE-housing Load eccentricities for pressure analysis in the PTFE sliding surface Load eccentricities for the analysis of the upper and lower bearing joint Spherical bearings Basics Design and dimensioning Design of the PTFE-housing Load eccentricities for the analysis of stresses in the PTFE sliding surfaces . . . . Load eccentricities for the analysis of the upper and lower bearing joints Stresses in the PTFE guide surfaces Deformation sliding bearings Basics Design and dimensioning Design basics for the PTFE-housing Load eccentricities for the analysis of the pressure in the PTFE sliding surface . Load eccentricities for the analysis of the upper and lower bearing joints Elastomer sliding bearings Basics Design and dimensioning Design of the PTFE-housing Load eccentricities for the analysis of the pressure in the PTFE sliding surface . Load eccentricities for the analysis of the upper and lower bearing joints

127 128 128 128 128 129 131 131 131 131 132 132 132 133 133 133 133 134 134 136 136 136 136 137 137 137 137

4.5 4.5.1 4.5.2 4.5.3 4.5.3.1 4.5.3.2 4.5.3.3 4.5.3.4 4.5.3.5 4.5.3.6 4.5.4 4.5.5 4.5.5.1 4.5.5.2

Deformation bearings History Applicable material Physical properties Rubber elasticity Shear modulus Elasticity modulus Stability Creep and relaxation Stick friction Future design rules Special reinforced elastomeric bearings Pre-adjusted elastomeric bearings with presetting Elastomeric bearings with low rotation resistance

137 138 138 140 140 141 146 146 146 147 151 153 153 153

XI 5

Standards

155

5.1

Preliminary remarks

155

5.2

Imprint from EN 1337-1: General design rules

156

5.3

Remarks on EN 1337-2: Sliding elements

179

5.4

Remarks on the draft of EN 1337-3: Elastomeric bearings

181

5.5

Remarks on the draft of EN 1337-5: Pot bearings

187

5.6

Remarks on EN 1337-7: Spherical and cylindrical PTFE-bearings

190

5.7

Remarks on the draft of EN 1337-8: Guide bearings and restraint bearings

192

5.8

Remarks on the draft of EN 1337-10: Inspection and maintenance

197

5.9

Imprint of EN 1337-11: Transport, storage and installation

200

6

Approvals

217

6.1

German Approval of sliding bearings (example)

218

6.2

German Approval of spherical bearings (two examples)

235

6.3

Pot bearing: special conditions (in part) and appendices

266

6.4

German Approval of a bearing for vibration control

274

7

Science and research

293

7.1

General

293

7.2 7.2.1

Research reports Long-term friction and wear tests with sliding bearings, different sliding surfaces Long-term friction and wear tests with PTFE sliding bearings, III c quality . . . . Investigation of friction behavior of PTFE through variation of the influence parameters: Sliding speed, pressure, bearing size, total way (wear), bearing system, load eccentricity Dependence of thickness on the temperature and size of elastomeric bearings .. Rupture tests with bearing plates Permissible horizontal forces for nonanchored bearings Permissible horizontal loads at nonanchored bearings: Supplementary tests on zinc-coated steel plates On the slip-resistance of nonanchored elastomeric bearings Determination of the characteristic values of the friction coefficients Steel bridge bearing movements Load-bearing capacity and reliability of reinforced concrete compression members Map of the lowest median daily temperature in Germany

293

7.2.2 7.2.3 7.2.4 7.2.5 7.2.6 7.2.7 7.2.8 7.2.9 7.2.10 7.2.11 7.2.12

293 294 295 295 298 298 299 299 300 300 301 301

XII

Contents

7.3 7.3.1 7.3.1.1 7.3.1.2 7.3.1.2.1 7.3.1.2.2 7.3.1.3 7.3.1.3.1 7.3.1.3.2 7.3.1.3.3 7.3.1.4 7.3.2 7.3.2.1 7.3.2.2 7.3.2.3 7.3.2.4 7.3.2.5 7.3.2.6 7.3.2.7 7.3.2.8

Approval tests Sliding bearing tests General Results of investigations on PTFE sliding bearings Model bearings Reviewed bridge bearings Results of investigations with composite sliding bearings Materials Testing technique Tribological behavior Summary Pot bearing tests General Material testing Control of finished test bearing Weariest Determination of the restoring moment Ultimate load test Permanent load test Summary and future work

302 302 302 303 304 332 334 334 336 337 338 342 342 342 343 343 343 346 347 347

8

Glossary

349

9

Literature

371

9.1 9.1.1 9.1.2 9.1.3 9.1.4 9.1.5

Literature, with brief comments General literature Historical literature Test reports Practical applications Analysis

371 371 373 374 374 377

9.2

Cited literature

380

Subject index

389