Elastomeric seismic-protection isolators — Part 6: High-durability and high-performance specifications and test methods

This document specifies specifications and test methods for elastomeric seismic isolators used for buildings to guarantee high durability and high performance. It is applicable to elastomeric seismic isolators used to provide buildings with protection from earthquake damage. The isolators covered consist of alternate elastomeric layers and reinforcing steel plates. They are placed between a superstructure and its substructure to provide both flexibility for decoupling structural systems from ground motion, and damping capability to reduce displacement at the isolation interface and the transmission of energy from the ground into the structure at the isolation frequency.

Appareils d'appuis structuraux en élastomère pour protection sismique — Partie 6: Titre manque

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Status
Published
Publication Date
21-Jul-2022
Current Stage
6060 - International Standard published
Due Date
20-Sep-2022
Completion Date
22-Jul-2022
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ISO 22762-6:2022 - Elastomeric seismic-protection isolators — Part 6: High-durability and high-performance specifications and test methods Released:22. 07. 2022
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INTERNATIONAL ISO
STANDARD 22762-6
First edition
2022-07
Elastomeric seismic-protection
isolators —
Part 6:
High-durability and high-performance
specifications and test methods
Reference number
ISO 22762-6:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 22762-6:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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© ISO 2022 – All rights reserved
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ISO 22762-6:2022(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 4

5 Classification ............................................................................................................................................................................................................ 4

6 Requirements .......................................................................................................................................................................................................... 5

6.1 General ........................................................................................................................................................................................................... 5

6.2 Type tests and routine tests ....................................................................................................................................................... 5

6.3 Functional requirements ........................................................................................................................................... .................... 5

6.4 Design compressive force and design shear displacement ............................................................................. 5

6.5 Performance requirements ......................................................................................................................................................... 5

6.5.1 General ........................................................................................................................................................................................ 5

6.5.2 Compressive properties ............................................................................................................................................ 14

6.5.3 Shear properties .............................................................................................................................................................. 14

6.5.4 Tensile properties ........................................................................................................................................... ................ 14

6.5.5 Dependencies of shear properties ................................................................................................................... 14

6.5.6 Dependencies of compressive properties ................................................................................................. 14

6.5.7 Shear displacement capacity ................................................................................................................................ 15

6.5.8 Durability ............................................................................................................................................................................... 15

6.6 Test pieces for type testing ....................................................................................................................................................... 15

6.6.1 General .....................................................................................................................................................................................15

6.6.2 Number of test pieces .................................................................................................................................................. 16

6.6.3 Scale of test pieces ......................................................................................................................................................... 17

6.7 Rubber material requirements ............................................................................................................................................. 17

6.8 Dimensional requirements ....................................................................................................................................................... 17

6.9 Requirements on steel used for flanges and reinforcing plates .............................................................. 17

6.10 Requirements on lead material for LRB........................................................................................................................ 17

7 Marking and labelling .................................................................................................................................................................................17

7.1 General ........................................................................................................................................................................................................ 17

7.2 Information to be provided ...................................................................................................................................................... 18

7.3 Additional requirements ............................................................................................................................................................ 18

7.4 Marking and labelling examples .......................................................................................................................................... 18

8 Test methods .........................................................................................................................................................................................................19

8.1 General ........................................................................................................................................................................................................ 19

8.2 Various dependence tests .......................................................................................................................................................... 19

8.2.1 Repeated deformation dependence of shear properties .............................................................. 19

8.2.2 Horizontal biaxial loading dependency ...................................................................................................... 21

8.2.3 Dependence of compression properties on shear strain .............................................................23

8.3 Ultimate properties under horizontal biaxial loading test .......................................................................... 23

8.3.1 Principle ..................................................................................................................................................................................23

8.3.2 Test machine ....................................................................................................................................................................... 24

8.3.3 Test piece ................................................................................................................................................................................ 24

8.3.4 Test conditions .................................................................................................................................................................. 24

8.3.5 Procedure .............................................................................................................................................................................. 24

8.3.6 Expression of results ................................................................................................................................................... 25

8.3.7 Test report ............................................................................................................................................................................. 25

8.4 Tensile testing ...................................................................................................................................................................................... 26

8.4.1 Allowable tensile strain ............................................................................................................................................26

8.4.2 Shear strain dependency of tensile yield strength ........................................................................... 27

iii
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ISO 22762-6:2022(E)

8.4.3 Shear strain dependency of allowable tensile strain ......................................................................28

8.4.4 Tensile fracture strain ................................................................................................................................................29

8.5 Durability ................................................................................................................................................................................................. 30

8.5.1 Cumulative shear strain ............................................................................................................................................30

8.5.2 Horizontal shear creep test and residual shear strain test ....................................................... 32

9 Quality assurance ............................................................................................................................................................................................34

Annex A (informative) Shear displacement capacity of various elastomeric seismic-

protection isolators .......................................................................................................................................................................................35

Annex B (informative) Example of the test method for ultimate properties under horizontal

biaxial loading .....................................................................................................................................................................................................41

Bibliography .............................................................................................................................................................................................................................45

© ISO 2022 – All rights reserved
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ISO 22762-6:2022(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www.iso.org/

iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,

Subcommittee SC 4, Products (other than hoses).
A list of all parts in the ISO 22762 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
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ISO 22762-6:2022(E)
Introduction

This document specifies requirements and test conditions for elastomeric seismic isolators used

for important buildings and buildings which can be subjected to frequent, large earthquakes; the

requirements and test conditions for the rubber material used in the manufacture of such isolators are

also specified.

Three grades of requirements for each test item are introduced. Grade I requirements for each test

item conform with the requirements given in ISO 22762-3 and are appropriate for standard buildings

unlikely to be subjected to frequent, large earthquakes. Grade II and grade III requirements for each test

item have to meet the more stringent requirements and be subjected to the more severe test conditions

given in this document. Grade III requirements for each test item are intended for the most important

buildings, and sites where large earthquakes can be particularly frequent.

There are a wide variety of requirements for seismic isolated buildings; there is no need to request the

same grade for all test items in the same project. Structural engineers may select grade II or III for each

test item in their requirements in order to perform the optimum building design.
Instances where this document differs from ISO 22762-3 include:
a) the number of test pieces to be used in type testing;

b) smaller tolerances allowed between measured properties and design characteristics;

c) smaller variations, due to effects such as temperature and compressive load, allowed in shear

properties.
© ISO 2022 – All rights reserved
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INTERNATIONAL STANDARD ISO 22762-6:2022(E)
Elastomeric seismic-protection isolators —
Part 6:
High-durability and high-performance specifications and
test methods
1 Scope

This document specifies specifications and test methods for elastomeric seismic isolators used for

buildings to guarantee high durability and high performance.

It is applicable to elastomeric seismic isolators used to provide buildings with protection from

earthquake damage. The isolators covered consist of alternate elastomeric layers and reinforcing steel

plates. They are placed between a superstructure and its substructure to provide both flexibility for

decoupling structural systems from ground motion, and damping capability to reduce displacement

at the isolation interface and the transmission of energy from the ground into the structure at the

isolation frequency.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:

Tension/compression testing machines — Calibration and verification of the force-measuring system

ISO 22762-1:2018, Elastomeric seismic-protection isolators — Part 1: Test methods

ISO 22762-3:2018, Elastomeric seismic-protection isolators — Part 3: Applications for buildings —

Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
allowable tensile strain

tensile strain whose influence on shear properties does not exceed a certain range

3.2
breaking

rupture of elastomeric isolator (3.8) due to compression- (or tension-) shear loading

3.3
buckling

state when elastomeric isolators (3.8) lose their stability under compression-shear loading

© ISO 2022 – All rights reserved
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ISO 22762-6:2022(E)
3.4
compressive properties
compressive stiffness for all types of rubber bearings
3.5
cumulative shear strain

sum of shear strain of a seismic-protection isolator when it is repeatedly deformed many times

3.6
design compressive stress

long-term compressive force on the elastomeric isolator (3.8) imposed by the structure

3.7
effective width

rectangular elastomeric isolator (3.8) smaller of the two side lengths of inner rubber to which direction

shear displacement is not restricted
3.8
elastomeric isolator

rubber bearing, for seismic isolation of buildings, bridges and other structures, which consists of multi-

layered vulcanized rubber sheets and reinforcing steel plates

EXAMPLE High-damping rubber bearings, linear natural rubber bearings and lead rubber bearings.

3.9
first shape factor

ratio of effectively loaded area to free deformation area of one inner rubber layer between steel plates

3.10
high-damping rubber bearing
HDR

elastomeric isolator (3.8) with relatively high damping properties obtained by special compounding of

the rubber and the use of additives
3.11
horizontal biaxial loading dependency
horizontal biaxial loading effect on various properties
3.12
horizontal shear creep test and residual shear strain test

changes in horizontal deformation that occur when the elastomeric isolator (3.8) is subjected to

a constant horizontal force for a long time due to strong winds such as a typhoon, and residual

deformation after unloading
3.13
inner rubber
rubber between multi-layered steel plates inside an elastomeric isolator (3.8)
3.14
lead rubber bearing
LRB

elastomeric isolator (3.8) with a lead plug or lead plugs press fitted into a hole or holes of the isolator

body to achieve damping properties
© ISO 2022 – All rights reserved
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ISO 22762-6:2022(E)
3.15
linear natural rubber bearing
LNR

elastomeric isolator (3.8) with linear shear force-deflection characteristics and relatively low damping

properties, fabricated using natural rubber

Note 1 to entry: Any bearing with relatively low damping can be treated as an LNR bearing for the purposes of

isolator testing.
3.16
roll-out

instability of an isolator with either dowelled or recessed connection under shear displacement

3.17
routine test

test for quality control of the production isolators during and after manufacturing

3.18
second shape factor

ratio of the diameter of the inner rubber (3.13) to the total thickness of

the inner rubber
3.19
second shape factor

ratio of the effective width (3.7) of the inner rubber (3.13)

to the total thickness of the inner rubber
3.20
shear strain dependency of allowable tensile strain

influence of the allowable tensile strain (3.1) due to a change of shear strain of elastomeric isolator (3.8)

3.21
shear strain dependency of tensile yield strength

influence of the tensile yield strength due to a change of shear strain of elastomeric isolator (3.8)

3.22
standard value

value of the isolator property defined by the manufacturer based on the results of the type test

3.23
structural engineer

engineer in charge of designing the structure for base-isolated bridges or buildings and responsible for

specifying the requirements for elastomeric isolators (3.8)
3.24
tensile fracture strain
strain at which elastomeric isolator (3.8) breaks in the tensile direction
3.25
type test

test for the verification of either material properties and isolator performances during the development

of the product or the achievement of the project design parameters
3.26
ultimate property

property at either buckling (3.3), breaking (3.2), or roll-out (3.16) of an isolator under compression-

shear loading
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ISO 22762-6:2022(E)
3.27
ultimate properties under horizontal biaxial loading test

critical characteristics of elastomeric isolators (3.8) when loaded in two directions in the horizontal

plane
3.28
ultimate property diagram
UPD

diagram giving the interaction curve of compressive stress and buckling (3.3) strain or breaking (3.2)

strain of an elastomeric isolator (3.8)
4 Symbols
For the purposes of this document, the symbols given in Table 1 apply.
Table 1 — Symbols and descriptions
Symbol Description
h equivalent damping ratio

K post-yield stiffness (tangential stiffness after yielding of lead plug) of lead rubber bearing

K shear stiffness
P tensile force at break of isolator
P tensile yield force
Q characteristic strength
S first shape factor
S second shape factor
γ maximum shear displacement
max
γ design shear strain
γ maximum torsion strain
γ ultimate shear strain under horizontal biaxial loading
γ maximum design shear strain during earthquake
max
γ ultimate shear strain under horizontal uniaxial loading
ε allowable limit of tensile strain
τ shear stress in bolt
τ shear static stress
5 Classification

The requirements for each test item of elastomeric seismic-protection isolators are classified into three

grades, grade III, grade II, and grade I, depending on durability and performance. Grade III and grade II

are high-endurance and high-performance specifications stipulated in this document, and the grade I is

a general specification prescribed by ISO 22762-3. In addition, grade III is more durable and has higher

performance specification than grade II.

The classification of each grade is shown in Table 2. Requirements for grade III and grade II are listed

in 6.5.

Structural engineers may select grade II or III for each test item in their requirements in order to

perform the optimum building design.
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ISO 22762-6:2022(E)
Table 2 — Classification of each grade
Grade Required items of Required performance level Required specimens
performance evaluation

I Required items of performance Required performance level is as Required specimens are as in

evaluation are as in ISO 22762- in ISO 22762-3:2018, Table 3. ISO 22762-3:2018, Table 4.

3:2018, Table 5.

II Some new performance items For some performance items, re- For some performance items, required

such as tensile property are quired performance level is spec- number and size of specimens are

added to those of grade I. ified severer than grade I. larger than grade I. In addition, for

some performance items, required
test condition is severer than grade I.
III For some performance items, re- For some performance items, required
quired performance level is spec- number and size of specimens are
ified severer than grade II. larger than grade II. In addition, for
some performance items, required
test condition is severer than grade II.
6 Requirements
6.1 General

Elastomeric isolators for buildings and the materials used in manufacture shall meet the requirements

specified in this clause. Test items for type test of isolators are shown in Table 3.

6.2 Type tests and routine tests
Type tests and routine tests are specified in ISO 22762-3:2018, 6.2.
6.3 Functional requirements

Functional requirements of elastomeric isolators used for buildings are specified in ISO 22762-3:2018,

6.3.
6.4 Design compressive force and design shear displacement

The design compressive forces, the design shear displacements, the design stress and the design strain

of an isolator are defined in ISO 22762-3:2018, 6.4.
6.5 Performance requirements
6.5.1 General
The performance requirements of grade II and III are shown below.

The isolators shall be tested and the results recorded using the specified test methods. They shall

satisfy all of the requirements of Grade II and III listed in Table 3. The test items are summarized in

Table 3 for type tests and routine tests. The standard value obtained from the tests shall be reported.

The standard temperature for determining the properties of elastomeric isolators is specified in

ISO 22762-3:2018, 6.1. Double-shear configuration testing (see ISO 22762-1:2018, 6.2.2.2) can be

employed with the approval of the structural engineer.

The standard values obtained from the tests satisfy the requirements shown in Table 4, Table 5 and

Table 6 depending to the type of isolators.
© ISO 2022 – All rights reserved
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ISO 22762-6:2022(E)
Table 3 — Tests on elastomeric isolators
Routine
Property Test item Test method Type test
test
Compressive Compressive stiffness ISO 22762-1:2018, 6.2.1,
X X
properties method 2
Shear properties Shear stiffness
Equivalent damping ratio
ISO 22762-1:2018, 6.2.2 X X
Post-yield stiffness (for LRB)
Characteristic strength (for LRB)
Tensile properties Tensile yield strength ISO 22762-1:2018, 6.5 N/A X
Allowable tensile strain 8.4.1 N/A X
Dependency of shear Shear strain dependency ISO 22762-1:2018, 6.3.1 N/A X
stiffness
Compressive stress dependency ISO 22762-1:2018, 6.3.2 N/A X
Frequency dependency ISO 22762-1:2018, 6.3.3 N/A X
Repeated loading dependency −1 ISO 22762-1:2018, 6.3.4 N/A X
Repeated loading dependency −2 8.2.1 N/A X
ISO 22762-1:2018, 6.3.5
Temperature dependency N/A X
ISO 22762-1:2018, 5.8
Horizontal biaxial loading dependency 8.2.2 N/A X
Dependency of com- Shear strain dependency ISO 22762-1:2018, 6.3.6 N/A X
pressive stiffness
Compressive stress dependency ISO 22762-1:2018, 6.3.7 N/A X
Dependency of tensile Shear strain dependency of tensile
8.4.2 N/A X
properties yield strength
Shear strain dependency of allowable
8.4.3 N/A X
tensile strain
Shear strain and dis- Ultimate shear strain, breaking strain,
placement capacity buckling strain, Ultimate property
diagram (UPD)
ISO 22762-1:2018, 6.4
or See Annex A and Annex B N/A X
for information.
Ultimate shear displacement, breaking
displacement, buckling displacement,
Ultimate property diagram (UPD)
Ultimate shear strain under horizontal
8.3 N/A X
biaxial loading
Tensile capacity Tensile fracture strength ISO 22762-1:2018, 6.5 N/A X
Tensile fracture strain 8.4.4 N/A X
Durability Property change ISO 22762-1:2018, 6.6.1 N/A X
Compressive creep ISO 22762-1:2018, 6.6.2 N/A X
Cumulative shear strain 8.5.1 N/A X
Horizontal shear creep test and 8.5.2
N/A X
residual shear strain test
X = test to be conducted with isolators; N/A = not applicable.
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ISO 22762-6:2022(E)
Table 4 — Performance requirement of LNR
Grade
Property Test item
III II
Compressive Compressive stiffness Tolerance
±15 % ±20 %
properties
Shear properties Shear stiffness Tolerance ±10 % ±15 %
Tensile properties Values at design
Tensile yield strength No requirement No requirement
shear strain
Allowable tensile Values at design
≥ 5 % ≥ 5 %
strain shear strain
Dependency of shear Allowable range of
stiffness Shea
...

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