ISO/TR 21136:2017

TECHNICAL ISO/TR
REPORT 21136
First edition
2017-04
Timber structures — Vibration
performance criteria for timber floors
Structures en bois — Critères de performance vibratoire pour les
planchers en bois
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Background . 1
5 Mechanism of timber floor vibration response to human normal walking actions.6
5.1 Characteristics of footstep force . 6
5.2 Responses of timber floors to the footstep force . 7
5.3 Parameters correlated to human acceptability of timber floor vibration. 8
5.4 General forms of human acceptability criterion of timber floor vibration . 8
6 Comprehensive procedure using a large database . 8
6.1 General . 8
6.2 Subjective evaluation procedure and questionnaire for laboratory floors . 9
6.3 Subjective evaluation procedure and questionnaire for field timber floors .10
6.4 Statistical analysis to derive human acceptability criterion from timber floor
vibration database .10
6.5 V erification of the criterion derived using a new database .11
7 Simplified procedure using a small database .11
Annex A (informative) Subjective evaluation questionnaire for laboratory floors used by
FPInnovations, Canada .12
Annex B (informative) An example of the application of the comprehensive procedure to
establish acceptability criterion for light frame timber floors in Canada .14
Annex C (informative) Example of application of the simplified procedure to establish
acceptability criterion (design criterion) for cross laminated timber (CLT) floors
in Canada .19
Annex D (informative) EC5 design criteria and calculation methods for criterion parameters .24
Annex E (informative) Hamm et al. design criteria and calculation methods for
criterion parameters .26
Bibliography .28
Foreword
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This document was prepared by Technical Committee ISO/TC 165, Timber structures.
iv © ISO 2017 – All rights reserved

Introduction
Timber floors are known to be prone to producing high level of vibration caused by human activities
due to the light-weight nature of these systems. Given that human tolerance to floor vibration is
rather subjective and could be influenced by a number of vibration response parameters, such as
frequency content, peak vibration level (e.g. displacement, velocity and acceleration), mean vibration
level and damping, there has not been any general agreement among researchers and code writers on
the human acceptability criteria for design against objectionable floor vibration. With the advent of
engineered timber floor products, it is necessary to provide generic guidelines on the establishment of
human acceptability criteria for specific floor construction product. With the appropriate calculation
procedures for response parameters, such human acceptability criteria can then be used by designers
to predict floor vibration performance at the design stage. Such human acceptability criteria can also
be used to evaluate floor vibration performance in the field or laboratory testing according to the test
[1]
procedures given in ISO 18324. To differentiate between these two types of human acceptability
criteria, in this report, the criterion uses the measured parameters is called “Performance criterion”,
and that uses the calculated parameters is called “Design criterion”.
Given that human tolerance levels to floor vibration may vary between countries due to cultural
differences, floor construction products, and construction practices, it is felt that floor vibration
performance criterion developed in one region may not be directly applicable to the others.
Consequently it is the view of the ISO/TC 165 that a more fruitful approach is to provide guideline
methods to individual countries and regions to develop their own human acceptability criterion. This is
the main purpose of this document.
The methods reviewed in this document are intended to be used for establishing human acceptability
criteria using the parameters that have been found to correlate well with human acceptability of
timber floor systems. Generally a study is required that includes measurement or calculation of these
parameters and a human subjective evaluation rating of the vibration performance of a number of floor
systems in the field or in the laboratory, and subsequent statistical analyses to determine the best human
acceptability criterion function. The proposed methods have been published in numerous research
reports and peer-reviewed papers based on significant research efforts over the last four decades. They
also have been validated by measurements and feedbacks on numerous field timber floors.
The potential floor vibration response parameters include fundamental natural frequency, static
deflection under a concentrated load, peak-velocity, peak-acceleration, and root-mean-square
acceleration. These parameters can be measured in the laboratory or in the field, and also can be
calculated.
A comprehensive procedure is provided to establish human acceptability criteria using the measured
or calculated response parameters and the subjective evaluation rating through advanced statistical
analysis of a large database of timber floors. If the categorical variables of the subjective rating
have more than two performance levels, a “Discriminant analysis” shall be used, while a “Logistic
regression” can be used for the case of two performance levels. A simplified procedure is also provided
for establishing human acceptability criteria using a relatively small database.
Annex A provides an example of questionnaire that was used in laboratory studies in Canada. Annex B
demonstrates the application of the comprehensive procedure to establish a performance criterion for
timber floors used in Canada (human acceptability criterion using measured criterion parameters).
Annex C shows the application of the simplified procedure to establish a design criterion (human
acceptability criterion using calculated parameters,) and the calculation formulae for the criterion
parameters for cross laminated timber (CLT) floors used in Canada. Annex D presents the design criteria
[5]
and the calculation formulae for the criterion parameters in EuroCode 5 (EC5). Annex E presents the
[8]
design criteria and the calculation formulae for the criterion parameters proposed by Hamm et al .
TECHNICAL REPORT ISO/TR 21136:2017(E)
Timber structures — Vibration performance criteria for
timber floors
1 Scope
This document provides a review of key floor vibration design criteria (human acceptability criterion
using calculated parameters) developed in research studies on timber floor around the world over the
last 30 years. Associated design methods are provided in the Annexes. The methods proposed in this
report are intended to be used for establishing human acceptability criteria for timber floor vibrations
induced by walking activities.
The proposed methods are applicable to the following timber floors: lightweight floors made of timber
joists and thin wood panel subfloor, heavy timber floors made of heavy timber beams with a thick
timber deck, and mass timber slab floors such as cross laminated timber (CLT), nail laminated timber
(NLT) and glued laminated timber.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Background
A substantial amount of research efforts has been undertaken to develop human acceptability criterion
for timber floor vibration control. Table 1 summarizes the most influential human acceptability criteria
using calculated parameters, which is simply called “Design criteria”. Table 1 also summarizes the
method used to develop the criterion, and the pros and cons of the criterion.
The Canadian National Building Code (NBC) presents provisions to control lumber joist floor vibration
[2]
through limiting the floor deflection under a 1 kN load, see Table 1. The NBC design criterion
[3]
was developed based on research efforts by FPInnovations scientists between 1970s and 1990s.
Across Canada survey was conducted in 1970s. The survey included field testing and interview of the
occupants using a comprehensive questionnaire. The questionnaire was developed in conjunction with
statisticians and psychologist. A conversational approach was used so that the interview did not alert
the occupants to the suspicion that the floor performance was likely to be of interest in
...