ISO 13033:2013

INTERNATIONAL ISO
STANDARD 13033
First edition
2013-08-01
Bases for design of structures —
Loads, forces and other actions —
Seismic actions on nonstructural
components for building applications
Bases du calcul des constructions — Charges, forces et autres actions
— Actions sismiques sur les composants non structurels destinés aux
applications du bâtiment
Reference number
©
ISO 2013
© ISO 2013
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ii © ISO 2013 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
1.1 General . 1
1.2 Relationship with ISO 3010 . 1
1.3 Components requiring evaluation . 1
1.4 Components excluded . 2
2 Normative references . 2
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 3
5 Seismic design objectives and performance criteria . 4
6 Sources of seismic demand on NSCS . 5
6.1 General . 5
6.2 Inertial demand . 5
6.3 Relative displacement demand . 5
6.4 Impact demand . 6
7 General conditions for determining seismic demand on NSCS . 6
7.1 General . 6
7.2 Determining seismic demand assuming NSCS does not influence building response . 6
7.3 Determining seismic demands assuming NSCS influences building response . . 7
8 Quantification of elastic seismic demand on NSCS . 7
8.1 General . 7
8.2 Inertial force demands determined by dynamic analysis . 7
8.3 Inertial elastic force demands determined by equivalent static analysis . 8
8.4 Seismic relative displacement demands .10
8.5 Impact demand .11
9 Verification of NSCS .11
9.1 Performance acceptance criteria.11
9.2 Verification by design analysis .12
9.3 Verification by seismic qualification testing .13
9.4 Verification by documented performance in past earthquakes (experience data) .15
9.5 Verification by a combination of procedures .15
10 Verification of seismic load path between NSCS and building structural system .15
11 Quality assurance and enforcement .16
Annex A (informative) Identification of NSCS requiring seismic evaluation .17
Annex B (informative) Principles for choosing importance factors for NSCS .20
Annex C (informative) Principles for choosing the floor response amplification factor
(height factor) .22
Annex D (informative) Principles for choosing the component amplification factor
(resonance factor).24
Annex E (informative) Principles for determining response modification factors .26
Annex F (informative) Principles for determining seismic relative displacements for drift-
sensitive components .27
Annex G (informative) Floor response spectra .29
Annex H (informative) Methods for verifying NSCS by design analysis .32
Annex I (informative) NSCS verification by shake table testing .35
Annex J (informative) NSCS verification through use of experience data .37
Annex K (informative) Principles of seismic anchorage of NSCS .38
Annex L (informative) Quality assurance in design and construction .42
Bibliography .43
iv © ISO 2013 – 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.
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. 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. 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.
The committee responsible for this document is ISO/TC 98, Bases for design of structures, Subcommittee
SC 3, Loads, forces and other actions
Introduction
This International Standard presents basic principles for the evaluation of seismic actions on
architectural, mechanical and electrical components and systems (i.e. nonstructural components) in
[1]
building applications. The seismic actions described are fundamentally compatible with ISO 2394.
This International Standard is intended to be a companion document to ISO 3010, Basis for design of
structures — Seismic actions on structures. It includes not only principles of seismic design but also
procedures for the verification of component and system capacity to ensure that those capacities exceed
seismic demands. Full verification of components and systems adequacy generally includes other actions
not addressed by this International Standard in combination with seismic actions.
This International Standard includes limit states associated with post-earthquake functionality of
nonstructural components. Some of these limit states address the overall safety of the building occupants,
while others address the safety of the surrounding community impacted by functional failure of the
facility. It therefore includes requirements for equipment and systems that demonstrate that they will
function as needed to achieve the overall safety goals following the earthquake.
The approach used in this International Standard is to first define the goals and performance
objectives and then determine the seismic demands on nonstructural components and systems. The
seismic demands, which are complex in nature, are initially described in a general way. Then, based
on reasonable assumptions, seismic demands are quantified in a simple manner that is efficient for
use in most situations. The simplified demands are based on the assumption that the seismic response
of nonstructural components and systems have a negligible effect on the primary response of the
structure. A series of annexes included with this International Standard provide informative guidance
on determining simplified coefficients, performing evaluation of components, and implementing
alternative testing/empirical procedures used for verification including those needed to demonstrate
functionality to achieve the overall post-earthquake safety goals.
vi © ISO 2013 – All rights reserved

INTERNATIONAL STANDARD ISO 13033:2013(E)
Bases for design of structures — Loads, forces and other
actions — Seismic actions on nonstructural components
for building applications
1 Scope
1.1 General
This International Standard establishes the means to derive seismic actions on nonstructural components
and systems (NSCS) supported by or attached to new or existing buildings. It also provides procedures
for the verification of NSCS seismic capacities. NSCS include architectural elements, mechanical and
electrical systems, and building contents.
This International Standard is not a legally binding and enforceable code. It is a source document that
is utilized in the development of codes of practice by the competent authority responsible for issuing
structural design regulations. This International Standard is intended for application by regional and
national standards committees when preparing standards for the seismic performance of NSCS.
This International Standard does not specifically cover industrial facilities, including nuclear power plants,
since these are dealt with separately in other International Standards. However, the principles in this
International Standard can be appropriate for the derivation of seismic actions for NSCS in such facilities.
NOTE 1 This International Standard has been prepared mainly for NSCS associated with engineered buildings.
The principles are, however, applicable to non-engineered buildings.
NOTE 2 Procedures for the verification of the supporting building structure for gravity and seismic actions
applied by the NSCS are outside the scope of this International Standard and are provided in ISO 3010.
1.2 Relationship with ISO 3010
This International Standard is a companion document to ISO 3010, Basis for design of structures —
Seismic actions on structures. ISO 3010 and its annexes provide basic seismic design criteria to be used
in the design of structures but they do not provide design criteria for NSCS (except for those that can
influence the structural response). For consistency, the terms and definitions that are in common with
ISO 3010 are also used in this International Standard.
The same ground motion criteria specified in ISO 3010 are also used in this International Standard. The
demand on NSCS is directly related to the response of the building in which they are located. Therefore,
the procedures used to determine the design ground motion and building seismic response are directly
referenced by this International Standard.
1.3 Components requiring evaluation
Evaluation of NSCS for seismic actions is required where any of the following apply:
a) the NSCS poses a falling hazard;
b) the failure of the NSCS can impede the evacuation of the building;
c) the NSCS contains hazardous materials;
d) the NSCS is necessary to the continuing function of essential facilities after the event; and
e) damage to the NSCS represents a significant financial loss.
Guidance for identification of NSCS that require seismic evaluation is provided in Annex A.
NOTE Pre-assembled modular mechanical and electrical units (e.g. heating and cooling modules) may be
treated as an assembly of components supported by the modular unit housing structure (see 9.5).
1.4 Components excluded
The requirements of this International Standard are not intended for application to furnishings, or
temporary or relocatable components (see Annex A).
With the exception of parapets (as described in Annex A), application of this International Standard to
components in buildings subject to low levels of seismic hazard may not be warranted.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 3010:2001, Basis for design of structures — Seismic actions on structures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3010 and the following apply.
3.1
ductility
ability to deform beyond the elastic limit under cyclic loading without significant reduction in strength
or energy absorption capacity
3.2
interstorey drift
lateral displacement within a storey
3.3
moderate earthquake ground motion
moderate ground motion caused by earthquakes which can be expected to occur during the service life
of the building
3.4
overstrength
increase in strength of a structural element above that designed or specified
Note 1 to entry: For nonstructural components, overstrength is used to provide an additional margin in the design of
anchorage and bracing to prevent premature failure of these elements. Overstrength factors are based on judgment.
3.5
restoring force
force exerted on the deformed component which tends to move the component to the original position
following earthquake motions
3.6
seismic hazard zone factor
factor to express the relative seismic hazard of the region
3.7
serviceability limit state
limit state beyond which the serviceability criteria of NSCS are no longer satisfied
2 © ISO 2013 – All rights reserved

3.8
structural factor
factor to reduce seismic design forces, taking into account ductility, acceptable deformation, restoring
force characteristics and overstrength (overcapacity) of the structure
3.9
ultimate limit state
limit state beyond which NSCS collapse, overturning, release of hazardous contents, or, in the case of
critical facilities, loss of function is expected to occur
Note 1 to entry: See Clause 5 a) for NSCS performance criteria for ultimate limit states.
4 Symbols and abbreviated terms
A acceleration at level i obtained from a dynamic analysis (see Annex G)
Di
A ordinate of the normalized floor response spectrum at level i
i
A parameter defining the normalized floor response spectrum for flexible components
flexible
A parameter defining the normalized floor response spectrum for rigid components
rigid
f , f , f , f frequencies defining floor response spectrum (see Annex G)
0 1 2 3
F design lateral seismic force of the NSCS attached at level i of the building structure for ULS
D,p,u,i
(F ) (SLS)
D,p,s,i
F elastic lateral seismic force of the NSCS attached at level i of the building structure for ULS
E,p,u,i
(F ) (SLS)
E,p,s,i
F weight of the NSCS
G,p
H average roof elevation of the structure relative to grade elevation
i level in the building structure of the point of attachment of the NSCS relative to grade
elevation
k nonstructural component response modification factor, to be specified according to its
D,p
ductility and overstrength
k floor response amplification factor for attachment location at level i
H,i
k ground motion intensity factor to be provided by regional and national standards;
Ι,u
(k )
Ι,s
k component amplification factor considering the effect of the natural periods of the NSCS
R,p
and the building
k NSCS amplification factor for flexible systems (k > 1,0)
R,p,flexible R,p,i,flexible
k NSCS amplification factor for rigid systems (k = 1,0)
R,p,i,rigid R,p,i,rigid
R inverse of the nonstructural factor k (see Annex E)
p,s p,s
R inverse of the nonstructural factor k (see Annex E)
p,u p,u
T component period
C
T jth modal period of the building structure
j
z elevation of level i relative to grade elevation
i
α parameter to account for increase in floor acceleration response over the height of the
building, that can be a function of the type of lateral-load resisting system
β ratio of vertical response to horizontal response
γ importance factor related to the required seismic reliability of the NSCS
n,E,p
5 Seismic design objectives and performance criteria
The fundamental seismic design objectives for NSCS are, in the event of an earthquake:
— to prevent human casualties associated with falling hazards and blockage of egress paths;
— to ensure post-earthquake continuity of life-safety functions within the building (e.g. sprinkler piping);
— to ensure continued post-earthquake operation of essential facilities (e.g. hospitals, fire stations);
— to maintain containment of hazardous materials;
— to minimize damage to property
To achieve the seismic design objectives, this International Standard establishes the following basic
performance criteria.
a) NSCS subjected to the severe earthquake ground motions that are specified at the building site
(ultimate limit state: ULS) should be designed, qualified by testing or qualified by experience data
to demonstrate that:
1) NSCS will not collapse, detach from the building structure, overturn or experience other forms
of structural failure, breakage or excessive displacement (sliding or swinging) that could cause
a life safety hazard;
2) NSCS will perform as required to maintain continuity of life safety functions (e.g. fire-fighting
systems, elevators, and other similar vital life safety systems);
3) NSCS will remain leak tight as required to prevent unacceptable release of hazardous materials
(e.g. vessels, tanks and piping and gas circulation systems that contain hazardous materials);
4) NSCS will operate as necessary immediately following the earthquake event to ensure continued
post-earthquake function of essential facilities.
b) NSCS subjected to the moderate earthquake ground motions specified at the building site (serviceability
limit state: SLS), will perform within accepted limits including limitation of financial loss.
NOTE 1 Recommendations for determining the severe (ULS) and moderate (SLS) design ground motions for a
given build site are provided in ISO 3010.
NOTE 2 It is recognized that complete protection against earthquake damage is not economically feasible for
most types of NSCS.
NOTE 3 Following an earthquake, earthquake-damaged buildings may need to be evaluated for safe occupation
during a period of time when aftershocks occur. This International Standard, however, does not address actions
on NSCS that can be expected due to aftershocks. In this case a model of the damaged building and components is
required to evaluate seismic actions.
4 © ISO 2013 – All rights reserved

6 Sources of seismic demand on NSCS
6.1 General
The following three sources of seismic demand should be considered when evaluating NSCS:
a) inertial acceleration demands;
b) relative displacement demands between points of attachment;
c) impact force demands resulting from interactions with other components or structural members.
These seismic demands are described in more details in 6.2 through 6.4 below. Principles for determining
these seismic demands are provided in Clause 7 and quantification of these seismic demands in terms of
recommended force equations are provided in Clause 8.
NOTE NSCS are generally classified as acceleration-sensitive or relative displacement-sensitive depending
upon which demand causes the most damage to the component during an earthquake. Anchored mechanical
equipment is typically considered acceleration-sensitive while building cladding is typically considered sensitive
to relative displacements (drift sensitive). For some NSCS, both demands are significant.
6.2 Inertial demand
All NSCS attached to buildings or their foundations are subjected to inertial demands. These inertial
demands are most generally described as acceleration motions at the points of attachment of the NSCS
and the structure. For points of attachment at the ground level or foundation level, these acceleration
motions are generally taken for design purposes as the earthquake design ground motions. At points
of attachment above the ground, the acceleration motions are modified by the dynamic response of the
building structural system to the earthquake ground motions. The modifications that have an influence
on these acceleration motions include the fundamental dynamic characteristics of the building structural
system (natural periods, damping, etc.), the relative location of the point of attachment within the structure
and the level and type of nonlinear behaviour that the building structural system experiences during the
earthquake. Most generally, the acceleration motion demand for NSCS are characterized in terms of floor
acceleration response spectra of the structural element (e.g. floor) to which the NSCS is attached. For the
most general case, both horizontal and vertical floor acceleration response spectra are defined.
In structural design, inertial demands are usually expressed in terms of force. The inertial force demand
on an individual component is a function of inertial acceleration demand at the points of attachment and
the dynamic properties of the components itself including its mass, stiffness, and nonlinear response
properties. For design purposes, this is often simplified as the product of a seismic coefficient and the
component weight.
A primary assumption of the inertial acceleration demand is that the dynamic response of the NSCS
has a negligible effect on the building response. If the effect is significant more complex methods are
required to determine the demand. See 7.3.
6.3 Relative displacement demand
Relative displacement demands occur during earthquake motions when the NSCS attachment (or support)
points experience unequal displacements (e.g. see Figure F.1). Sources of relative displacements are:
a) relative displacements of attachment points that are located at different floor levels of a building;
b) relative displacements of attachment points that are located on independent, seismically
separated buildings;
c) relative displacements of attachment points that are located on two NSCS attached to the same or
different floors, including components on vibration isolators;
d) relative displacements of attachment points located on NSCS and the building;
e) relative displacements of attachment points that are located on seismically isolated building and its
foundation or between seismically isolated floors.
Relative displacement demands are predominately horizontal in nature although vertical relative
displacement demands are also possible. Inter-storey drifts of a building are transformed into relative
displacement demands by multiplying the earthquake-caused drift ratio by the vertical distance between
points of attachment. As with the inertial demand, the relative displacement demands are a function of
the earthquake displacement response of the building structure to which the NSCS is attached and for
some situations, the earthquake displacement response of the NSCS is also important.
Stresses from relative displacement demands are typically determined from static analysis where
points of attachment are displaced. Stresses in NSCS induced by relative displacement demands should
be within acceptable limits.
Relative displacement demands may also result in loss of bearing support. Bearing seat width should be
adequate to accommodate relative displacement demands.
A primary assumption of the above approach for determining relative displacement demand is that the
strength, mass and stiffness of the connecting NSCS will have a negligible effect on the building response.
If the effect is significant, the NSCS should be included in the structural model or more complex methods
are required to determine the demand (see 7.2).
6.4 Impact demand
Impact demands on NSCS are the result of collisions with the structural system or other NSCS. These
collisions occur when the clearance between adjoining NSCS or between NSCS and the building is
insufficient. To avoid impact demands of NSCS with other NSCS or structural systems, either adequate
clearance or seismic restraints should be provided. In some instances this impact is unavoidable, as in
the case of seismic snubbers supporting vibrating equipment. Where adequate clearance or restraint
cannot be provided, it may be necessary to accept the damage from impact. The determination of impact
demands requires higher order analysis and testing. The determination of adequate clearances to avoid
damaging impact demands also requires special evaluation.
See 8.5 for additional discussion.
7 General conditions for determining seismic demand on NSCS
7.1 General
The determination of seismic demands imposed on NSCS should consider the response of the supporting
building to ground motion and the interaction of the structure and the NSCS. In this International Standard,
it is generally assumed that the response of the NSCS has a negligible effect on the building structure
earthquake response. This assumption is valid if certain conditions specified in 7.2 are satisfied.
7.2 Determining seismic demand assuming NSCS does not influence building response
For NSCS which are primarily inertial demand sensitive, it is acceptable to treat the NSCS as a
secondary component
a) if the mass of the NSCS is small relative to the building mass or the mass of that portion of the
building structure to which the component is attached, or
b) if the participation of the NSCS mass in the overall seismic response (even though relatively large
compared to the building mass) is distributed uniformly over the building structure or a larger part
of the building structure (e.g. cladding, piping systems).
If the NSCS is not directly attached to the building structure (e.g. attached to ground floor slab) or is
attached in a manner that prevents it from influencing the overall building seismic response it is always
acceptable to exclude the NSCS dynamic model from the building dynamic model.
6 © ISO 2013 – All rights reserved

For NSCS which are primarily sensitive to relative displacements of the building, it is acceptable to
assume that the NSCS does not influence the building response
a) if the strength and/or stiffness of NSCS which are attached at more than one level of a building are
small relative to the strength and stiffness of the lateral force resisting system of the building, or
b) if the presence of the NSCS does not alter the boundary conditions of the building structure or its
structural components that would have unfavourable effects on the seismic response of the building
or the NSCS itself.
7.3 Determining seismic demands assuming NSCS influences building response
For situations where the NSCS response can influence the building response, the potential influence of
the NSCS on the building seismic response should be considered. NSCS that influence the overall building
seismic response whether due to mass, strength or stiffness contribution, or change to boundary
condition should be included in the building structural model as required by 6.3 of ISO 3010:2001.
NOTE In general, the mass of NSCS should be included in the building structural analysis, either explicitly or
as an allowance regardless if the nonstructural response does not influence the building response.
8 Quantification of elastic seismic demand on NSCS
8.1 General
Seismic demands on NSCS are typically quantified as design seismic forces and or design seismic relative
displacements. This section quantifies the determination of elastic baseline seismic demands in terms of:
a) accelerations;
b) relative displacements between different floors of the supporting building;
c) relative displacements between supporting buildings or other items to which NSCS are attached;
d) interactions with other NSCS.
Elastic baseline inertial force demands (see 8.2) may be modified for needed reliability as expressed
through importance factors (Annex B) and overstrength and energy-dissipation characteristics of NSCS
as represented by response modification factors (Annex E). These modifications are addressed in 9.2 of
this International Standard.
NOTE The term elastic seismic demand implies that demand is determined assuming the NSCS remains
elastic and that the response is not modified to account for factors such as required reliability (importance),
overstrength or energy-dissipation characteristics of the NSCS. It is not meant to imply that the building structure
also remains elastic when determining the demand.
8.2 Inertial force demands determined by dynamic analysis
Inertial force demands on NSCS should be quantified as the product of the acceleration demand and the
component mass. It is always acceptable to obtain acceleration demands on NSCS by dynamic analysis
of supporting building(s). The acceleration demands are expressed either in terms of the peak floor
acceleration, peak inertial acceleration of the component, floor response spectra or acceleration time
histories of the floor motion. The type of demand should be consistent with the method of verification
as specified in Clause 9 of this International Standard.
Floor response spectra may be established for a specific case or generically for a wide range of buildings.
Specific floor response spectra are developed from dynamic analysis of supporting buildings, while
generic spectra are typically determined using static coefficient values derived from the simplified
equivalent static force equations (see 8.3.2). For specific floor response spectra, nonlinear response of
the supporting buildings should be considered due to the possibility of modification of seismic demands
on NSCS resulting from the building inelastic response. See further discussion of floor response spectra
in Annex G, and more details of performing dynamic analysis of supporting buildings in Clause 9 of
ISO 3010:2001.
Dynamic analysis of both the building and NSCS in a combined single model can be required for certain
cases. Specifically, where there can be significant interaction between more massive components and
the supporting structure, such a procedure is recommended. (See 7.3 and Annex G of this International
Standard.) In this case detailed modelling of the connection to the structure as well as the local
structural members that support the NSCS, should be considered to develop the inertial force demands.
The design of the structure for the combined effects should be evaluated in accordance with 6.3 and 9.5
of ISO 3010:2001.
8.3 Inertial elastic force demands determined by equivalent static analysis
8.3.1 General
It is permitted to determine inertial elastic force demands on NSCS using equivalent static analysis
force procedures. The equivalent static force elastic demand may be computed directly from a combined
dynamic analysis of the building and NSCS. For those NSCS which may be assumed to not influence the
building response, the equivalent static elastic force demands may be determined from:
a) floor response spectra using the ratio of natural frequencies of NSCS and supporting building; or
b) the elastic equivalent static force in 8.3.2.
See 9.2 for more information on static coefficients and Annex G for more information on floor
response spectra.
8.3.2 Basic elastic equivalent static forces
The elastic equivalent static seismic forces for ULS and SLS earthquake levels are given as follows:
a) ULS (Ultimate Limit State);
The elastic seismic force on NSCS attached at the ith level of the building structure for ULS, F , is given by
E,p,u,i
Fk=⋅kk⋅⋅F
Ep,,ui,,Iu Hi,,Rp Gp,
b) SLS (Serviceability Limit State);
The elastic seismic force on NSCS attached at the ith level of the building structure for SLS, F , is given by
E,p,s,i
Fk=⋅kk⋅⋅F
Ep,,si,,Is Hi,,Rp Gp,
where
F is the elastic lateral seismic force on the NSCS attached at the ith level of the building
E,p,u,i
(F ) structure for ULS (SLS);
E,p,s,i
k is the ground motion intensity factor to be provided by regional and national standards;
Ι,u
(k )
Ι,s
k is the floor response amplification factor at the attachment at level i (see Annex C);
H,i
k is the component amplification factor considering the effect of the natural periods of the
R,p
NSCS and the building (see Annex D);
F is the weight (m·g) on the NSCS.
G,p
8 © ISO 2013 – All rights reserved

8.3.3 Horizontal acceleration
The horizontal equivalent static elastic acceleration demand is the product of the ground motion
intensity factor (k , k ), floor response amplification factor (k ), and the component amplification
Ι,u Ι,s H,i
factor (k ). The procedures for determining these factors are given in 8.3.3.1, 8.3.3.2 and 8.3.3.3.
R,p
8.3.3.1 Ground motion intensity factor (normalized peak ground acceleration)
The ground motion intensity factor (k , k ) is related to the regional seismicity, local site effects, and
Ι,u Ι,s
the designated earthquake levels. In general, peak ground acceleration values are represented by the
ground motion intensity factor normalized to gravitational acceleration (in units of g). If the peak ground
velocity or other spectral ordinates are given, those values should be transformed into acceleration and
normalized to develop the value of the ground motion intensity factor.
The ground motion intensity factor corresponds to that used for the supporting building. In accordance
with ISO 3010, the ground motion intensity factor (k , k ) is given by:
Ι,u Ι,s
kk=⋅k
Iu,,ZE u
kk=⋅k
Is,,ZE s
where
k is the seismic zoning factor;
Z
k is the seismic ground motion intensity.for ULS
E,u
k is the seismic ground motion intensity.for SLS
E,s
8.3.3.2 Floor response amplification factor (height factor)
The floor response amplification factor (k ) represents the dynamic amplification of the specified floor
H,i
acceleration response over the height of the building with respect to the ground acceleration. The floor
response amplification factor is generally determined as a function of the ratio of the height of the point
of attachment of the NSCS to the average height of the building in which the component is located.
Considering effects from higher modes of the supporting building, the floor response amplification factor
can be determined using a modal analysis of the supporting building. Alternatively, the floor response
modification factor may be determined using simplified analysis proceedures as described in Annex C.
8.3.3.3 Component amplification factor (resonance factor)
The component amplification factor (k ) represents the dynamic amplification of NSCS response
R,p
as a function of the ratio of the natural frequencies of the NSCS and supporting building. Component
amplification factors can be obtained from a floor response spectrum based on the natural frequencies
of the NSCS. The natural frequencies of supporting building can be obtained from a representative model
of the building developed in accordance with ISO 3010. The natural frequencies of NSCS may be obtained
by calculation, pull-and-release tests, impact tests, or shake table tests. The method used should be
appropriate to the type of component being assessed. Nevertheless, considering that the natural
frequencies of the supporting building and the NSCS are usually unavailable in practice, component
amplification factors of NSCS may be tabulated according to the rigid or flexible characteristics of the
NSCS. See Annex D for more information.
8.3.4 Vertical acceleration
Similar to horizontal acceleration demands, vertical acceleration demands for NSCS should be quantified
using analogous factors for the vertical direction: the ground motion intensity factor, floor response
amplification factor, and component amplification factor.
For the vertical ground motion intensity factor, the normalized vertical peak ground acceleration may be
used. Where this information is not available, it may be taken as 1/2 to 2/3 of the normalized horizontal
peak ground acceleration (see Annex G), except in the near-field of shallow focus earthquakes where
vertical accelerations can be significantly higher. See Clause 8 and Annex E of ISO 3010:2001 for more
information about vertical ground acceleration.
For NSCS design, in general, dynamic amplification of floor response with respect to ground acceleration
in the vertical direction can be limited. Therefore, the component amplification factor k for vertical
R,p
floor response is generally taken as 1,0.
NOTE The out-of-plane response associated with certain types of flexible floors and roofs can amplify vertical
response. In these cases, consideration of additional response amplification may be warranted. In addition,
research indicates that vertical floor accelerations can be amplified in seismically isolated buildings. Finally, the
attachment design of vertical acceleration-sensitive equipment, such as vibration-isolated equipment, should
consider the possibility of additional resonant vertical seismic demands that exceed the vertical ground motion.
8.4 Seismic relative displacement demands
8.4.1 General
The NSCS relative displacement demands should be quantified for displacement-sensitive components as
the seismic relative displacement expected between points of attachment of the component for both ULS
and SLS earthquake levels. For NSCS connected between floors, such as glazing, the relative displacement
demands are the relative displacements between floors of the same building. For NSCS which span
across seismic separation joints, the relative displacement demand is the displacement (considering all
applicable degrees of freedom) between the NSCS attachment points on each structure. For NSCS which
span horizontally between flexible equipment on the same floor or different floors, such as piping, the
seismic demand is the relative displacement between points of attachment to the equipment. Relative
displacement demands are typically determined by elastic equivalent static analysis and are the demands
expected for ULS and SLS ground motion levels unmodified by inelastic reduction factors.
NOTE The effect of seismic relative displacements should be considered in combination with displacements
caused by other loads as appropriate. Specific details on determining relative displacement seismic demands are
pro
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