ISO 4866:1990/Amd 1:1994

INTERNATIONAL IS0
STANDARD
4866
First edition
I 990-08-o I
AMENDMENT 1
1994-l Z-01
Mechanical vibration and shock - Vibration
of buildings - Guidelines for the
measurement of vibrations and evaluation
of their effects on buildings
AMENDMENT 1
Vibrations et chocs mkaniques - Vibrations des batiments - Lignes
directrices pour le mesurage des vibrations et &valuation de leurs effets sur
/es ba^ timen ts
AMENDEMENT 7
Reference number
IS0 4866: 1990/Amd. 1: 1994(E)

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IS0 4866:1990/Amd.l:1994(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be
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and non-governmental, in liaison with ISO, also take part in the work. IS0
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(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approvai by at least 75 % of the member bodies casting
a vote.
Amendment 1 to IS0 48663990 was prepared by Technical Committee
ISO/TC 108, Mechanical vibration and shock, Subcommittee SC 2,
Measurement and evaluation of mechanical vibration and shock as applied
to machines, vehicles and structures.
0 IS0 1994
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microfilm, without permission in writing from the publisher.
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ii

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@ IS0 IS0 4866:1990/Amd.l:I994(E)
Mechanical vibration and shock - Vibration of buildings -
Guidelines for the measurement of vibrations and
evaluation of their effects on buildings
AMENDMENT 1
Page iii
Change the last sentence to: “Annexes A to E of this International Standard are for information only.”
Page 17
Add the following annex as annex D and change the present annex D to annex E.
Page 18
Add references [24] to [38] to annex E.

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IS0 4866:1990/Amd.l:1994(E) @ IS0
Annex D
(informative)
Predicting natural frequencies and damping of buildings
Introduction
T=k2Hfi . . . 02 .
IS0 4866:1990 specifies methods of measuring
where
building response including fundamental natural
frequencies. When direct measurements cannot be
D is the width parallel to the force, in metres;
made or are limited in usefulness by high damping,
sub-component resonances or other practical prob-
k2 ranges from 0,087 sm-3/2 to 0,109 sm-3/2
lems, it becomes necessary to estimate natural fre-
quency and damping values.
(references [25] and [281).
This annex offers guidance on the ways in which the
T = k3 H fi func(H,D,I) . . . 03 .
fundamental natural frequency and associated damp-
ing value may be assessed. It draws attention to the
uncertainties involved which should be taken into
(see, for example, reference 1291).
account wherever an estimation of fundamental
natural frequencies of a building is used in measuring
NOTE 1 k, has the units sm-I; k2 has the units smB3 ’*.
or evaluation procedures.
A later study [30], considering a sample of 163 rec-
tangular-plan buildings, recommended f = 46/H Hz-m
D.l Predicting natural frequencies of tall
(i.e. T = 0,022H sm-I) for the fundamental translation
buildings using empirical methods
mode, f = 58/H Hz-m for the orthogonal fundamental
translation mode and f = 72/H Hz-m for the fun-
There are many empirical formulae for predicting the
damental torsional mode (sample size of 63 buildings).
T, of the fundamental
frequency fr or period
translation mode; of these the simplest isf= IO/N Hz
0,l N s), where N is the number of storeys.
(i.e. T =
NOTE 2 These formulae for fare empirical. They may also
Various other formulae are given in the codes of be considered as numerical value equations yielding values
off in hertz when values of H in metres are inserted, for
different countries and these can be grouped into
instance f = 46/H.
three categories:
T=k,H . . . Dl .
Figure D.l shows the resulting fit of the curve
f = 46/H Hz-m to the data and it can be appreciated
where
that large errors are likely to be encountered. It can be
is the height, in metres;
H seen that errors of * 50 % are not uncommon, and
this is typical of the accuracy which can be expected
T is the period, in seconds;
using empirical formulae. Based on measured data, it
appears that the mode shapes of the fundamental
k, ranges from 0,14 sm-1 to 0,03 sm-1
modes of tall buildings can be reasonably approxi-
mated by straight lines.
(references [24] to 1271).

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IS0 4866:1990/Amd.l:1994(E)
@ IS0
properties of buildings. Predictions of fundamental
D.2 Predicting natural frequencies of tall
frequencies should therefore be treated with caution.
buildings using computer-based methods
It has long been realised that comparatively large Special methods have been developed for analysis of
errors are likely to occur using the simple empirical core buildings [31], shear buildings [32] and sway
formulae, but it has also been generally accepted that frame and frame buildings [33], but with any method it
a satisfactory estimate of frequency can be obtained is important to check whether the method has been
using one of the standard computer-based methods. calibrated using a range of reliable experimental data
However, buildings are complicated structures and it and to understand what errors are likely to be
is not a simple task to create an accurate encountered. If the method has not been proven, then
consequently it must be accuracies greater than those obtained for empirical
mathematical model;
predictors should not be assumed. Only the
accepted that these models will only provide
fundamental frequencies have been discussed, but
approximate predictions. In a study [30] examining
the predicted frequencies of higher frequency modes
published evidence, the correlation between
will suffer from similar or (more probably) greater
computed frequencies and measured frequencies
errors. This means that, except for special cases
was actually considerably worse than the correlation
between the frequencies predicted using f = 46/H where the mathematical model has been tuned to
Hz-m and the measured values. This discrepancy can experimental results, predictions involving many
be attributed to inadequacies in modelling the real calculated modes must be
...