ISO 22762-3:2005
(Main)Elastomeric seismic-protection isolators - Part 3: Applications for buildings - Specifications
Elastomeric seismic-protection isolators - Part 3: Applications for buildings - Specifications
ISO 22762 applies to elastomeric seismic isolators used to provide buildings or bridges with protection from earthquake damage. The isolators covered consist of alternate elastomer 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. ISO 22762-3:2005 specifies the requirements for elastomeric seismic isolators used for buildings and the requirements for the rubber material used in the manufacture of such isolators. The specification covers requirements, design rules, manufacturing tolerances, marking and labelling and test methods for elastomeric isolators.
Appareils d'appuis structuraux en élastomère pour protection sismique — Partie 3: Applications pour bâtiments — Spécifications
General Information
Relations
Frequently Asked Questions
ISO 22762-3:2005 is a standard published by the International Organization for Standardization (ISO). Its full title is "Elastomeric seismic-protection isolators - Part 3: Applications for buildings - Specifications". This standard covers: ISO 22762 applies to elastomeric seismic isolators used to provide buildings or bridges with protection from earthquake damage. The isolators covered consist of alternate elastomer 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. ISO 22762-3:2005 specifies the requirements for elastomeric seismic isolators used for buildings and the requirements for the rubber material used in the manufacture of such isolators. The specification covers requirements, design rules, manufacturing tolerances, marking and labelling and test methods for elastomeric isolators.
ISO 22762 applies to elastomeric seismic isolators used to provide buildings or bridges with protection from earthquake damage. The isolators covered consist of alternate elastomer 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. ISO 22762-3:2005 specifies the requirements for elastomeric seismic isolators used for buildings and the requirements for the rubber material used in the manufacture of such isolators. The specification covers requirements, design rules, manufacturing tolerances, marking and labelling and test methods for elastomeric isolators.
ISO 22762-3:2005 is classified under the following ICS (International Classification for Standards) categories: 83.140.99 - Other rubber and plastics products; 91.120.25 - Seismic and vibration protection. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 22762-3:2005 has the following relationships with other standards: It is inter standard links to ISO 22762-3:2010. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase ISO 22762-3:2005 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of ISO standards.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 22762-3
First edition
2005-07-15
Elastomeric seismic-protection
isolators —
Part 3:
Applications for buildings —
Specifications
Appareils d'appuis structuraux en élastomère pour protection
sismique —
Partie 3: Applications pour bâtiments — Spécifications
Reference number
©
ISO 2005
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ii © ISO 2005 – All rights reserved
Contents Page
Foreword. v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols and abbreviated terms . 4
5 Classification. 8
5.1 General. 8
5.2 Classification by construction . 8
5.3 Classification by ultimate properties. 10
5.4 Classification by tolerance on shear properties . 10
6 Requirements . 11
6.1 General. 11
6.2 Type tests and routine tests . 12
6.3 Functional requirements. 12
6.4 Design compressive force and design shear displacement . 13
6.5 Performance requirements . 13
6.6 Rubber material requirements. 19
6.7 Dimensional requirements. 20
6.8 Requirements on steel used for flanges and reinforcing plates . 21
7 Design rules . 22
7.1 General. 22
7.2 Shape factor . 22
7.3 Compression and shear properties . 23
7.4 Ultimate properties . 24
7.5 Reinforcing steel plates . 26
7.6 Connections . 27
8 Manufacturing tolerances . 27
8.1 General. 27
8.2 Measuring instruments . 27
8.3 Plan dimensions . 27
8.4 Product height. 28
8.5 Flatness . 29
8.6 Horizontal offset. 30
8.7 Plan dimensions of flanges . 31
8.8 Flange thickness. 31
8.9 Tolerances on positions of flange bolt holes . 32
9 Marking and labelling . 32
9.1 General. 32
9.2 Information to be provided . 32
9.3 Additional requirements . 33
9.4 Marking and labelling examples. 33
10 Test methods. 33
11 Quality assurance. 33
Annex A (normative) Tensile stress in reinforcing steel plate . 34
Annex B (informative) Confirmation list. 36
Annex C (informative) Determination of ultimate property diagram based on experimental results . 38
Annex D (informative) Minimum recommended physical properties of rubber material. 41
Annex E (informative) Effect of inner-hole diameter and second shape factor on shear properties . 43
Annex F (informative) Determination of compressive properties of elastomeric isolators. 46
Annex G (informative) Determination of shear properties of elastomeric isolators. 49
Annex H (informative) Method of predicting buckling limit at large deformations. 54
Annex I (informative) Design of fixing bolts and flanges . 60
Bibliography . 63
iv © ISO 2005 – All rights reserved
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 22762-3 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 4, Products (other than hoses).
ISO 22762 consists of the following parts, under the general title Elastomeric seismic-protection isolators:
Part 1: Test methods
Part 2: Applications for bridges — Specifications
Part 3: Applications for buildings — Specifications
Introduction
This International Standard contains two parts related to specifications for isolators — one for bridges and the
other for buildings — since the requirements for isolators for bridges and for buildings are quite different,
although the basic concept of the two products is similar. Therefore, when this International Standard is
applied to the design of bridge isolators, Part 2 and the relevant clauses in Part 1 are used and, when it is
applied to building isolators, Part 3 and the relevant clauses in Part 1 are used.
The main differences to be noted between isolators for bridges and isolators for buildings are as below:
a) Isolators for bridges are mainly rectangular in shape and those for buildings circular in shape.
b) Isolators for bridges are designed to be used for both rotation and horizontal displacement, while isolators
for buildings are designed for horizontal displacement only.
c) Isolators for bridges are designed to perform on a daily basis to accommodate length changes of bridges
caused by temperature changes as well as during earthquakes, while isolators for buildings are designed
to perform only during earthquakes.
d) Isolators for bridges are designed to withstand dynamic loads caused by vehicles on a daily basis as well
as earthquakes, while isolators for buildings are mainly designed to withstand dynamic loads caused by
earthquakes only.
For structures that are neither buildings nor bridges (e.g. tanks), the structural engineer may use either Part 2
or Part 3 of this International Standard, depending on the requirements of the structure.
vi © ISO 2005 – All rights reserved
INTERNATIONAL STANDARD ISO 22762-3:2005(E)
Elastomeric seismic-protection isolators —
Part 3:
Applications for buildings — Specifications
1 Scope
ISO 22762 applies to elastomeric seismic isolators used to provide buildings or bridges with protection from
earthquake damage. The isolators covered consist of alternate elastomer 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.
This part of ISO 22762 specifies the requirements for elastomeric seismic isolators used for buildings and the
requirements for the rubber material used in the manufacture of such isolators. The specification covers
requirements, design rules, manufacturing tolerances, marking and labelling and test methods for elastomeric
isolators.
Some items of classification and some requirements need to be confirmed before production and these should
be reviewed using the list given in Annex B.
2 Normative references
The following referenced documents are indispensable for the application 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 630, Structural steels — Plates, wide flats, bars, sections and profiles
ISO 1052, Steels for general engineering purposes
ISO 1629, Rubber and latices — Nomenclature
ISO 3302-1, Rubber — Tolerances for products — Part 1: Dimensional tolerances
ISO 22762-1:2005, Elastomeric seismic-protection isolators — Part 1: Test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
breaking
rupture of elastomeric isolator due to compression (or tension)-shear loading
3.2
buckling
state when elastomeric isolators lose their stability under compressive-shear loading
3.3
compressive properties of elastomeric isolator
compressive stiffness (K ) for all types of rubber bearings
v
3.4
compressive-shear testing machine
machine used to test elastomeric isolators, which has the capability of shear loading under constant
compressive load
3.5
cover rubber
rubber wrapped around the outside of inner rubber and reinforcing steel plates before or after curing of
elastomeric isolators for the purpose of protecting the inner rubber from deterioration due to oxygen, ultraviolet
rays and other natural elements and protecting the reinforcing plates from corrosion
3.6
design compressive stress
long-term compressive force on the elastomeric isolator imposed by the structure
3.7
effective loaded area
area sustaining vertical load in elastomeric isolators, which corresponds to the area of reinforcing steel plates
3.8
effective width
〈rectangular elastomeric isolator〉 the smaller of the two side lengths of inner rubber to which direction shear
displacement is not restricted
3.9
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
NOTE Types of such isolators include high-damping rubber bearings, linear natural rubber bearings and lead rubber
bearings.
3.10
first shape factor
ratio of effectively loaded area to free deformation area of one inner rubber layer between steel plates
3.11
high-damping rubber bearing
HDR
elastomeric isolator with relatively high-damping properties obtained by special compounding of the rubber
and the use of additives
2 © ISO 2005 – All rights reserved
3.12
inner rubber
rubber between multi-layered steel plates inside an elastomeric isolator
3.13
lead rubber bearing
LRB
elastomeric isolator whose inner rubber with a lead plug or lead plugs press fitted into a hole or holes of the
isolator body to achieve damping properties
3.14
linear natural rubber bearing
LNR
elastomeric isolator with linear shear force-deflection characteristics and relatively low-damping properties and
fabricated using natural rubber
NOTE Any bearing with relatively low damping may be treated as an LNR bearing for the purposes of isolator testing.
3.15
maximum compressive stress
maximum compressive stress acting briefly on elastomeric isolators during an earthquake
3.16
nominal compressive stress
long-term compressive stress recommended by the manufacturer for the isolator, including the safety margin
3.17
roll-out
instability of an isolator with either dowelled or recessed connection under shear displacement
3.18
routine test
a test for quality control of the production isolators during and after manufacturing
3.19
second shape factor
〈circular elastomeric isolator〉 ratio of the diameter of the inner rubber to the total thickness of the inner rubber
〈rectangular or square elastomeric isolator〉 ratio of the effective width of the inner rubber to the total thickness
of the inner rubber
3.20
shear properties of elastomeric isolators
a comprehensive term that covers characteristics determined from isolator tests:
shear stiffness (K ) for LNR;
h
shear stiffness (K ) and equivalent damping ratio (h ) for HDR and LRB;
h eq
post-yield stiffness (K ) and characteristic strength (Q ) for LRB.
d d
3.21
structural engineer
engineer who is in charge of designing of structure for base-isolated bridges or buildings and is responsible for
specifying the requirements for elastomeric isolators
3.22
type test
test for verification either of material properties and isolator performances during development of the product
or that project design parameters are achieved
3.23
ultimate properties
properties at either buckling, breaking, or roll-out of an isolator under compressive-shear loading
3.24
ultimate property diagram
UPD
diagram giving the interaction curve of compressive stress and buckling strain or breaking strain of an
elastomeric isolator
4 Symbols and abbreviated terms
For the purposes of all three parts of ISO 22762, the symbols given in Table 1 apply.
Table 1 — Symbols and definitions
Symbol Definition
A effective plan area; plan area of elastomeric isolator excluding cover rubber portion
A
effective area of bolt
b
A overlap area between the top and bottom elastomer area of isolator sheared under non-seismic
e
displacement
A
load-free area of isolator
free
A
loaded area of isolator
load
A
p area of the lead plug for a lead rubber bearing
a
side length of square elastomeric isolator excluding cover rubber thickness, or length in
longitudinal direction of rectangular isolator excluding cover rubber thickness
a length of the shorter side of the rectangular isolator including cover rubber thickness
e
a' length in longitudinal direction of the rectangular isolator, including cover rubber thickness
B effective width for bending of flange
b length in transverse direction of the rectangular isolator, excluding cover rubber thickness
b' length in transverse direction of the rectangular isolator, including cover rubber thickness
c
distance from centre of bolt hole to effective flange section
D' outer diameter of circular isolator, including cover rubber
D
diameter of flange
f
d
inner diameter of reinforcing steel plate
i
d
diameter of bolt hole
k
4 © ISO 2005 – All rights reserved
d
outer diameter of reinforcing steel plate
o
E
ap apparent Young’s modulus of bonded rubber layer
E
apparent Young’s modulus corrected, if necessary, by allowing for compressibility
c
s
apparent Young’s modulus corrected for bulk compressibility depending on the shape factor (S )
E 1
c
E
bulk modulus of rubber
∞
E
Young’s modulus of rubber
F
tensile force on isolator by uplift
u
G
shear modulus
G γ
( ) equivalent linear shear modulus at shear strain γ
eq
H height of elastomeric isolator including mounting flange
H
height of elastomeric isolator excluding mounting flange
n
h
eq equivalent damping ratio
h γ
( )
equivalent damping ratio as a function of shear strain
eq
K
post-yield stiffness (tangential stiffness after yielding of lead plug) of lead rubber bearing
d
K
shear stiffness
h
K
initial shear stiffness
i
K
p shear stiffness of lead plug inserted in lead rubber bearing
K
shear stiffness of lead rubber bearing before inserting lead plug
r
K
tangential shear stiffness
t
K
compressive stiffness
v
L
length of one side of a square flange
f
M resistance to rotation
M
moment acting on bolt
f
M
moment acting on isolator
r
n
number of rubber layers
n
number of fixing bolts
b
P compressive force
P
design compressive force
P
maximum design compressive force
max
P
min minimum design compressive force
P
Tb tensile force at break of isolator
P
Ty tensile force at yield of isolator
Q
shear force
Q
shear force at break
b
Q
shear force at buckling
buk
Q
characteristic strength
d
S
first shape factor
S
second shape factor
T temperature
T total rubber thickness, given by T = nt×
r r r
t
thickness of one rubber layer
r
tt,
thickness of rubber layer laminated on each side of plate
r1 r2
t
thickness of one reinforcing steel plate
s
t
thickness of outside cover rubber
o
U γ
( ) function giving ratio of characteristic strength to maximum shear force of a loop
V
uplift force
v
loading velocity
W
energy dissipated per cycle
d
X shear displacement
X
design shear displacement
X
shear displacement at break
b
X
shear displacement at buckling
buk
X
shear displacement due to quasi-static shear movement
s
X
maximum design shear displacement
max
X
shear displacement due to dynamic shear movement
d
Y compressive displacement
Z section modulus of flange
α
coefficient of linear thermal expansion
γ
shear strain
6 © ISO 2005 – All rights reserved
γ
design shear strain
γ
upper limit of the total of design strains on elastomeric isolators
a
γ
shear strain at break
b
γ
local shear strain due to compressive force
c
γ
shear strain due to dynamic shear movement
d
γ
maximum shear strain during earthquake
max
γ
local shear strain due to rotation
r
γ
shear strain due to quasi-static shear movement
s
γ
ultimate shear strain
u
δ
horizontal offset of isolator
H
δ
difference in isolator height measured between two points at opposite extremes of the isolator
V
ε
compressive strain of isolator
ε
creep strain
cr
ε
tensile strain of isolator
T
ε
tensile strain at break of isolator
Tb
ε
Ty tensile strain at yield of isolator
ζ
ratio of total rubber height to total height of rubber and steel layers
θ
rotation angle of isolator about the diameter of a circular bearing or about an axis through a
rectangular bearing
θ
rotation angle of isolator in the longitudinal direction (a)
a
θ
rotation angle of isolator in the transverse direction (b)
b
λ
correction factor for calculation of stress in reinforcing steel plates
η
correction factor for calculation of critical stress
κ correction factor for apparent Young’s modulus according to hardness
Σγ
total local shear strain
ρ
safety factor for roll-out
R
ρ
safety factor for tensile force
T
σ
compressive stress in isolator
σ
design compressive stress
σ
tensile stress in bolt
B
σ
bending stress in flange
b
σ
b allowable bending stress in steel
f
σ
critical stress in isolator
cr
σ
allowable tensile stress in steel
f
σ
maximum design compressive stress
max
σ
minimum design compressive stress
min
σ
for building: nominal long term compressive stress recommended by manufacturer
nom
σ
tensile stress in reinforcing steel plate
s
σ
allowable tensile stress in steel plate
sa
σ
sy yield stress of steel for flanges and reinforcing steel plates
σ
tensile strength of steel for flanges and reinforcing steel plates
su
σ
tensile stress
t
σ
allowable tensile stress in isolator
te
σ
yi yield stress in steel plate
τ
shear stress in bolt
B
τ
allowable shear stress in steel
f
φ
factor for computation of buckling stability
ψ
factor for computation of buckling check
ξ factor for computation of critical stress
5 Classification
5.1 General
Elastomeric isolators are classified by construction, their ultimate properties, and tolerances on their
performance.
5.2 Classification by construction
Elastomeric isolators are classified by construction as shown in Table 2.
Other methods not listed in Table 2 may be used to fix flanges to the laminated rubber if the resulting
construction has adequate strength to resist the shear forces and bending moments due to shear deflection.
Furthermore, such constructions shall be capable of resisting tension if the elastomeric isolator is designed for
uplift.
8 © ISO 2005 – All rights reserved
Table 2 — Classification by construction
Mounting flanges are
bolted to connecting
flanges, which are
bonded to the laminated
rubber.
Cover rubber is added
before curing of isolator.
Type I
Mounting flanges are
bolted to connecting
flanges, which are
bonded to the laminated
rubber.
Cover rubber is added
after curing of isolator.
Mounting flanges are
Type II directly bonded to the
laminated rubber.
Isolators without
Recess connection
mounting flanges,
Type III
connected to base by
either recess rings or
dowell pins.
Dowell connection
5.3 Classification by ultimate properties
Elastomeric isolators may be classified by their ultimate properties as shown in Table 3. The ultimate
properties are defined as the compressive stress and the shear strain when the isolator reaches the ultimate
state. The ultimate state of the isolator is defined as buckling, breaking or roll-out (see Annex C).
Table 3 — Classification by ultimate properties
Ultimate
W 350 % 300 % u < 350 % 250 % u < 300 % 200 % u < 250 % 150 % u < 200 % 150 % >
γ γ γ γ γ γ
u u u u u u
shear strain
Class A B C D E F
Isolators are designated using the ultimate shear strain γ at a nominal compressive stress σ and at a
u nom
compressive stress of 2 × σ , where σ is taken as the long-term stress and 2 × σ as the
nom nom nom
maximum short-term compressive stress during an earthquake. A recommended value of σ is given by
nom
the manufacturer.
The shear strain in the ultimate state may be determined, at each of these two compressive stresses, by the
methods specified in Annex C and Annex H.
The way in which the designation code of an isolator is derived is illustrated by the following example:
At σ = 8 N/mm , γ = 320 %. The isolator is therefore class B under these conditions.
nom u
At 2 × σ = 16 N/mm , γ = 240 %. The isolator is therefore class D under these conditions.
nom u
The designation code is therefore:
N8B-M16D (the stress value is always rounded to the nearest whole number)
where N denotes nominal and M maximum.
NOTE In the selection of isolators for a particular project, the ultimate properties under both maximum compressive
stress and minimum compressive stress need to be considered. The classification in Table 3 provides a guide for bolted
isolators in situations where the minimum stress is not tensile.
5.4 Classification by tolerance on shear properties
Elastomeric isolators are classified by tolerance on shear properties as shown in Table 4.
Table 4 — Classification by tolerance of shear properties
Class Individual Global
S-A
± 15 % ± 10 %
S-B ± 25 % ± 20 %
10 © ISO 2005 – All rights reserved
6 Requirements
6.1 General
Elastomeric isolators for buildings and the materials used in their manufacture shall meet the requirements
specified in this clause. For test items (see Table 5) that have no specific required values, the manufacturer
shall define the values and inform the purchaser prior to production.
The standard temperature for determining the properties of elastomeric isolators is 23 °C in accordance with
prevailing International Standards. However, it is advisable to establish a range of working temperatures
taking into consideration actual environmental temperatures and possible changes in temperature at the work
site where the elastomeric isolators are installed.
Table 5 — Test pieces for type testing
Properties Test item Test piece
Compressive properties Compressive stiffness Full-scale only
Shear stiffness
Shear properties Full-scale only
Equivalent damping ratio
Tensile properties Tensile fracture strength Scale B
Shear strain dependency Full-scale only
Compressive stress dependency Full-scale only
Dependency of shear
Frequency dependency Scale A, STD, SBS
properties
Repeated loading dependency Scale B
Temperature dependency Scale A, STD, SBS
Shear strain dependency
Dependency of compressive
Scale B
properties
Compressive stress dependency
Breaking strain
Ultimate properties Buckling strain Scale B
Roll-out strain
Ageing Scale A, STD, SBS
Durability
Creep Scale A
Scale A: Scaling such that, for a circular bearing, diameter W 150 mm, for a rectangular bearing,
side-length W 100 mm, and, for both types, rubber layer thickness W 1,5 mm and thickness of
reinforcing steel plates W 0,5 mm.
Scale B: Scaling such that, for a circular bearing, diameter W 500 mm, for a rectangular bearing,
side-length W 500 mm and, for both types, rubber layer thickness W 1,5 mm and thickness of
reinforcing steel plates W 0,5 mm. Minimum scale factor 0,5.
STD = standard test piece (see Tables 10 and 11 of ISO 22762-1:2005).
SBS = shear-block test piece specified in ISO 22762-1:2005, 5.8.3. With LRB, SBS shall only be
used for ageing tests.
NOTE Some of these properties may be determined using one of the standard test pieces detailed in Tables 10
and 11 in ISO 22762-1:2005. The standard test pieces are used for non-specific product tests, such as testing in the
development of new materials and products.
6.2 Type tests and routine tests
Testing to be carried out on elastomeric isolators is classified into “type tests” and “routine tests”.
Type tests shall be conducted either to ensure that project design parameters have been achieved (in which
case the test results shall be submitted to the structural engineer for review prior to production) or to verify
isolator performance and material properties during development of the product. The test piece for each type
test shall be full-scale or one of the options specified in Table 5. The test piece shall not have been subjected
to any previous test programme. The tests shall be performed on test pieces not subjected to any scragging,
unless the production isolators are to be supplied after scragging. In that case, the test pieces shall be
subjected to the same scragging procedure as the production isolators.
Previous type test results may be substituted provided the following conditions are met:
a) Isolators are fabricated in a similar manner and from the same compound cured under the same
conditions.
b) All corresponding external and internal dimensions are within 10 % of each other.
c) The second shape factors are within ± 10 %.
d) The test conditions, such as maximum vertical load applied in the ultimate property test (see 6.5.7), are
more severe.
e) For the ultimate property test (6.5.7) and compressive stress dependency test (6.5.5.2), the previous test
results were obtained on isolators with a smaller or equal second shape factor S in the cases of that S
2 2
is less than 5.
f) The previous test results were obtained within a period accepted by the structural engineer.
Routine tests are carried out during production for quality control. Sampling is allowed for routine testing.
Sampling shall be conducted randomly and cover not less than 20 % of the production of any isolator design.
For a given project, tests shall cover not less than four test pieces for each size and not less than 20 test
pieces in total. If isolators are supplied after scragging, the routine test shall be performed on scragged
isolators.
6.3 Functional requirements
Elastomeric isolators for buildings are designed and manufactured to have the performance characteristics
required so that they deform in all directions with the proper stiffness (with damping, if required) during an
earthquake.
In the application of elastomeric isolators, attention shall be paid to the following points:
a) The isolators shall be installed horizontally between the structure and foundation.
b) Once installed, the isolators shall not be subjected to a constant shear force.
c) When isolators are to be installed under relatively flexible columns, the rotation at the top of the isolator
caused by bending deformation shall be carefully considered.
d) Exposed steel surfaces, such as the surfaces of mounting flanges, shall be properly painted or galvanized
to prevent rusting.
e) Proper maintenance shall be carried out on installed isolators to prevent any abnormalities such as
distortion, cracks or rust occurring.
f) Fire protection of the isolators may be required.
g) The seismic gap shall be maintained at all times.
12 © ISO 2005 – All rights reserved
6.4 Design compressive force and design shear displacement
The design stress and strain of an isolator are defined by the following relationships with the design force and
the displacement:
P P P
0 max min
σ = , σ = , σ =
0 max min
A A A
X X
0 max
γ = , γ =
0 max
T T
r r
The design compressive forces P , P and P and design shear displacements X and X for an
0 max min 0 max
isolator shall be provided by the structural engineer. If the P , P , P , X and X are not known at
0 max min 0 max
the time of type testing, the design stress and design strain to be used for testing can be determined as
follows:
σσ= , σσ= 2
0nom max nom
σ , γ and γ as determined by the manufacturer.
min 0 max
6.5 Performance requirements
6.5.1 General
The isolators shall be tested and the results recorded by the specified test methods. They shall satisfy all of
the requirements listed below. The design value for each isolator shall be specified prior to the tests. The test
items are summarized in Table 6 which indicates those type tests that are optional, where a material test
piece may substitute for an isolator, and the tests to be performed as routine tests.
6.5.2 Compressive properties
a) Requirements:
The compressive stiffness K shall be within ± 30% of the design value.
v
b) Test piece:
The test piece shall be a full-scale isolator for the type test and a production isolator for the routine test.
c) Test conditions:
As specified in ISO 22762-1:2005, 6.2.1.5.2, method 2, cyclic loading with the design compressive stress
σ ± 30 % shall be carried out for three cycles.
The compressive stiffness K shall be computed from the third cycle.
v
The standard test temperature is 23 °C. If the test is carried out at a different temperature, the result shall
be corrected to the value of the property at 23 °C by an appropriate method.
Table 6 — Tests on isolators
Routine Type test
Properties Test items Test method
test
Compressive properties Compressive stiffness ISO 22762-1:2005, 6.2.1,
X X
Method 2
Shear properties Shear stiffness
ISO 22762-1:2005, 6.2.2 X X
Equivalent damping ratio
Tensile properties Tensile fracture strength ISO 22762-1:2005, 6.5 N/A Opt.
Dependency of shear Shear strain dependency ISO 22762-1:2005, 6.3.1 N/A X
properties
Compressive stress dependency ISO 22762-1:2005, 6.3.2 N/A Opt.
Frequency dependency ISO 22762-1:2005, 6.3.3 N/A X(m)
Repeated loading dependency ISO 22762-1:2005, 6.3.4 N/A X
ISO 22762-1:2005, 6.3.5
Temperature dependency N/A X(m)
(m) ISO 22762-1:2005, 5.8
Dependency of Shear strain dependency ISO 22762-1:2005, 6.3.6 N/A Opt.
compressive properties
Compressive stress dependency ISO 22762-1:2005, 6.3.7 N/A Opt.
Ultimate properties Breaking strain
Buckling strain ISO 22762-1:2005, 6.4 N/A X
Roll-out strain
Durability Property change ISO 22762-1:2005, 6.6.1 N/A X(m)
Creep ISO 22762-1:2005, 6.6.2 N/A X
X = test to be conducted with isolators; X(m) = test can be conducted either with isolators or with shear-block test
pieces.
N/A = not applicable; Opt. = optional.
6.5.3 Shear properties
a) Requirements:
The following properties shall be within the specified range of design value corresponding to the adopted
tolerance class specified in 5.4.
The test items specified for each type of isolator are shown in Table 7. The properties measured for LRB
may be selected from either L-1 or L-2, as given in the table.
Table 7 — Shear property test items
Isolator type Test items
LNR
Shear stiffness K
h
HDR
Shear stiffness K , equivalent damping ratio h
h eq
LRB L-1
Shear stiffness K , equivalent damping ratio h
h eq
L-2
Post-yield stiffness K , characteristic strength Q
d d
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b) Test piece:
The test piece shall be a full-scale isolator for the type test and a production isolator for the routine test.
c) Test conditions:
The test piece shall be loaded with the design compressive stress σ .
Cyclic loading to the design shear strain γ or to the shear strain which corresponds to γ = 100 % shall
be carried out for three cycles.
The required properties shall be computed from the third cycle.
If the test is performed at a frequency different from the design isolation frequency, the result shall be
corrected to the design frequency or to 0,5 Hz by an appropriate method.
The standard test temperature is 23 °C. If the test is carried out at a different temperature, the result shall
be corrected to the value of the property at 23 °C by an appropriate method.
Double-shear configuration testing (see ISO 22762-1:2005, 6.2.2.2) can be employed with the approval of
the structural engineer.
6.5.4 Tensile properties
a) Requirements:
The tensile properties shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator or a scale model, as specified in Table 5.
c) Test conditions:
The test conditions shall be as specified in ISO 22762-1:2005, 6.5.
6.5.5 Dependencies of shear properties
6.5.5.1 Shear strain dependency
a) Requirements:
The change in each property over the range of test shear strains with respect to the value of the property
at the design shear strain γ (or another reference strain, if employed in the shear property test 6.5.3)
shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator.
c) Test conditions:
The shear properties shall be determined at strains between 50 % and the maximum shear strain γ
max
at strain intervals of 50 %; the interval between the last two test strains shall be at least 50 %. The
change in the property, normalized using the value corresponding to the design strain, shall be
determined. Tests can also be performed at 10 % and 20 % shear strain.
Double-shear configuration testing (see ISO 22762-1:2005, 6.2.2.2) can be employed with the approval of
the structural engineer.
6.5.5.2 Compressive stress dependency
a) Requirements:
As the compressive stress varies, the change in the shear properties with respect to the value of the
property at the design stress σ shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator.
c) Test conditions:
The shear properties shall be determined at 0, 0,5σ , 1,0σ , 1,5σ , 2,0σ and the maximum tensile
0 0 0 0
stress, if applicable, and the change in the property, normalized using the value corresponding to the
design strain, shall be determined.
Double-shear configuration testing (see ISO 22762-1:2005, 6.2.2.2) can be employed with the approval of
the structural engineer.
6.5.5.3 Frequency dependency
a) Requirements:
The frequency dependency shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator, a scale model, a standard test piece or a shear-block test
piece, as specified in Table 5.
c) Test conditions:
The shear strain amplitude shall be γ .
Other test conditions shall be as specified in ISO 22762-1:2005, 6.3.3.
Double-shear configuration testing (see ISO 22762-1:2005, 6.2.2.2) can be employed with the approval of
the structural engineer.
6.5.5.4 Repeated loading dependency
a) Requirements:
The repeated loading dependency shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator or a scale model, as specified in Table 5.
c) Test conditions:
The shear strain amplitude shall be γ .
Other test conditions shall be as specified in ISO 22762-1:2005, 6.3.4.
Double-shear configuration testing (see ISO 22762-1:2005, 6.2.2.2) can be employed with the approval of
the structural engineer.
16 © ISO 2005 – All rights reserved
6.5.5.5 Temperature dependency
a) Requirements:
The temperature dependency shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator, a scale model, a standard test piece, or a shear-block test
piece, as specified in Table 5.
c) Test conditions:
The shear strain amplitude shall be γ .
Other test conditions shall be as specified in ISO 22762-1:2005, 6.3.5.
Double-shear configuration testing (see ISO 22762-1:2005, 6.2.2.2) can be employed with the approval of
the structural engineer.
6.5.6 Dependencies of compressive properties
6.5.6.1 Shear strain dependency
a) Requirements:
The shear strain dependency of the compressive properties shall be within the specified range.
b) Test piece:
The test piece shall be a full-scale isolator or a scale model, as specified in Table 5.
c) Test conditions:
The test conditions shall be a
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