SIST EN 13036-5:2019

SLOVENSKI STANDARD
SIST EN 13036-5:2019
01-november-2019
Značilnosti cestnih in letaliških površin - Preskusne metode - 5. del: Določanje
indeksov vzdolžnih neravnin
Road and airfield surface characteristics - Test methods - Part 5: Determination of
longitudinal unevenness indices
Oberflächeneigenschaften von Straßen und Flugplätzen - Prüfverfahren - Teil 5:
Bestimmung der Längsunebenheitindizes
Caractéristiques de surface des routes et aérodromes - Méthodes d’essais - Partie 5 :
Détermination des indices d’uni longitudinal
Ta slovenski standard je istoveten z: EN 13036-5:2019
ICS:
17.040.20 Lastnosti površin Properties of surfaces
93.080.10 Gradnja cest Road construction
93.120 Gradnja letališč Construction of airports
SIST EN 13036-5:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 13036-5:2019

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SIST EN 13036-5:2019


EN 13036-5
EUROPEAN STANDARD

NORME EUROPÉENNE

September 2019
EUROPÄISCHE NORM
ICS 17.040.20; 93.080.10
English Version

Road and airfield surface characteristics - Test methods -
Part 5: Determination of longitudinal unevenness indices
Caractéristiques de surface des routes et aérodromes - Oberflächeneigenschaften von Straßen und
Méthodes d'essais - Partie 5 : Détermination des Flugplätzen - Prüfverfahren - Teil 5: Bestimmung der
indices d'uni longitudinal Längsunebenheitindizes
This European Standard was approved by CEN on 21 July 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13036-5:2019 E
worldwide for CEN national Members.

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Contents Page
European foreword . 3
Introduction . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviations . 8
5 Calculation of evenness indices . 8
6 International Roughness Index (IRI) . 10
6.1 General . 10
6.2 Representation of the obtained results . 11
7 Wave band analysis . 11
7.1 General . 11
7.2 Wave band indices . 12
8 Weighted Longitudinal Profile (WLP) analysis . 12
8.1 General . 12
8.2 Prerequisites . 12
9 Reporting . 13
Annex A (normative) Calculation of the IRI . 14
Annex B (informative) Example code for IRI calculation . 18
Annex C (informative) Wave band analysis using bi-octave bands and RMS . 20
Annex D (informative) Wave band analysis using LPV over selected wavelengths . 42
Annex E (informative) Calculation of the WLP . 45
Annex F (informative) Indicator implementation check . 52
Bibliography . 53

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European foreword
This document (EN 13036-5:2019) has been prepared by Technical Committee CEN/TC 227 “Road
materials”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by March 2020, and conflicting national standards shall
be withdrawn at the latest by March 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
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Introduction
Through road/vehicle dynamic interaction and vehicle vibration, the road profile evenness affects
safety (tyre contact forces), ride quality, energy consumption, vehicle wear as well as pavement and
road durability. The road profile evenness is consequently key information for road maintenance-
management-systems and performance control.
The purpose of this document is to provide a standard practice for calculating and reporting estimates
of road evenness from digitized longitudinal profiles.
This practice covers the mathematical processing of longitudinal profile measurements to produce
evenness statistics (indices) covering the wavelength range 0,5 m to 50 m. These wavelengths cover
1)
most situations for cars . The practice describes the calculation procedure for the International
Roughness Index (IRI), wave band analysis (Root Mean Square (RMS) and Longitudinal Profile Variance
(LPV)) and the Weighted Longitudinal Profile (WLP).
The purpose of the practice is to ensure that when applying one of the possible procedures, exactly the
same steps are carried out, with the aim of facilitating the comparison of evenness measurements
carried out with different profiling instruments in European countries. The Wave band analysis
procedures are informative and therefore IRI is preferred as benchmarking parameter.
NOTE As a control of the implementation of calculation of the evenness indices, three longitudinal profiles
are available including the “true values”. They can be found at www.erpug.org in the directory reference profiles.
More on this can be found in Annex F.

1) For higher speed, e.g. on airport runways or highways, longer wavelengths could also be important.
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1 Scope
This document specifies the mathematical processing of digitized longitudinal profile measurements to
produce evenness indices. The document describes the calculation procedure for the International
Roughness Index (IRI), Root Mean Square (RMS) and Longitudinal Profile Variance (LPV) from three
separate wavelength bands and the σWLP and ΔWLP from the Weighted Longitudinal Profile (WLP).
The purpose of this document is to provide a standard practice for calculating and reporting estimates
of road evenness from digitized longitudinal profiles. Other aims with this document are to facilitate the
comparison of evenness measurement results carried out with different profiling instruments in
European countries.
The evenness range covered in this document is defined as the wavelength range 0,5 m to 50 m. It is
noted that both shorter and longer wavelengths can also influence the driving comfort but those are not
covered in this document.
The quantified evenness indices derived from this document are useful support for pavement
management systems. The output can also be used for type approval and performance control of new
and old pavements. The indices can be used on rigid, flexible and gravel road surfaces.
This document doesn’t define from what position on the road the longitudinal profile should be
obtained.
The derived indices are portable in the sense that they can be obtained from longitudinal profiles
measured with a variety of instruments.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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 https://www.iso.org/obp
3.1
reporting repetition interval
measurements made over the road surface which are often analysed using shorter parts or samples to
allow for a more precise description of the measured profile and which is the length of such a sample
Note 1 to entry: For more information on samples see key 4, l to l in Figure 1
0 n
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Key
1 longitudinal profile
2 B to C profile measurement length
3 A to D overall profilometer route
4 l …l reporting repetition interval
0 n
Figure 1 — Profile lengths definitions
3.2
longitudinal evenness
deviation of the longitudinal profile from a straight line in a defined wavelength range, e.g. 0,5 m to 50
m
3.3
longitudinal profile
intersection between the pavement surface and a conventional reference plane perpendicular to the
pavement surface and parallel to the lane direction
Note 1 to entry: Usually one of the profiles measured in the wheel paths is used.
Note 2 to entry: The longitudinal road profile is typically saved every 50 mm or 100 mm (acquisition repetition
interval).
3.4
measuring path
selected intersection path, of all possible profiles along the transverse direction
3.5
pre-processed profile
profile obtained by applying resampling and filtering procedures
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3.6
profile
profile of the surface that is described by two coordinates: one in the surface plane following the line of
travel of the profilometer called distance (the abscissa), and the other in a direction normal to the
surface plane, called vertical displacement (the ordinate)
3.7
profilometer
instrument to measure and collect profiles covering the evenness from, e.g., roads and airfields
3.8
profile measurement length
length of an uninterrupted profile measurement and which expresses the length over which the
profilometer continuously and accurately digitises and records the profile (from point B to C in
Figure 1)
Note 1 to entry: Most profilometers need to run for some minimum distance before and after the
profile they are to measure; these starting (from point A to B in Figure 1) and ending phases (from point
C to D, in Figure 1) should not be included in the profile measurement length.
3.9
longitudinal raw profile
profile given by a profilometer when measuring a longitudinal road profile, the characteristics of which
depend on the profilometer used
3.10
resampling
procedure applied on the original measured profile (longitudinal raw profile) to create a new profile
with an alternative sampling distance
3.11
spatial frequency
N
reciprocal of a wavelength in cycles per metre that defines the number of waves N, of wavelength λ, per
metre:
1
N= (1)
λ
3.12
acquisition repetition interval
absolute value of the difference of abscissa between two adjacent points of the digitised longitudinal
profile line
Note 1 to entry: This definition assumes that the distance measured by the profilometer, which is
usually related to the curvilinear abscissa, is close enough to the abscissa in the mathematical sense
3.13
wavelength
quantity describing the horizontal dimension of the irregularities of a longitudinal profile
Note 1 to entry: Longitudinal wavelength is normally expressed in metres (m) or millimetres (mm) and
is a descriptor of the wavelength components of the profile and is related to the concept of the Fourier
Transform of a series regularly sampled measurement points along a spatial axis.
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3.14
wheel paths
area of a pavement surface where the large majority of vehicle wheel passages are concentrated
4 Symbols and abbreviations
B is the base used for IRI calculation in metres (m). It is the length over which the IRI
calculation is performed (or reporting length using the terminology of this document)
L denotes the measurement length
N
1
is the spatial frequency, in cycles per metre: N= ; N is usually called a wave number
λ
x is the abscissa of the sampled point i, in metres (m)
i
z is the elevation of the profile determined at the sampling point i, in metres or millimetres
i
δ is the acquisition repetition interval for the digitization of the profile, in metres or millimetres
x
λ
is the wavelength, in metres (m)
Δ sample interval
IRI is the International Roughness Index
WB is the wave band index calculated by using root mean square analysis applied to the pre-
processed profile elevations for the wave band W, in metres
RMS root means square
SW is the Root Mean Square value for the short wavelength band
LPV longitudinal profile variance
MW is the Root Mean Square value for the medium wavelength band
LW is the Root Mean Square value for the long wavelength band
w is the waviness of the reference spectrum used for the WLP
WLP is the Weighted Longitudinal Profile
σWLP is the standard deviation of the WLP
ΔWLP is the range of variation of the WLP
5 Calculation of evenness indices
A profile can be obtained starting from any lateral position in the lane. This document doesn’t specify
which of those profiles that should be used, only how to calculate any of the four evenness indices
specified.
The calculation of evenness indices, involves the following steps:
— the measurement of the profile, which includes identification of the start and end points of the
profile measurement length and possible events (e.g. roundabouts, speed bumps, milestones, etc.);
— if the purpose is benchmarking it is preferred that the profile are sampled with a 0,1 m step. It is
essential to consider the method of resampling to avoid erroneous energy in the signal;
— the calculation of one or more indices;
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Pre-processing including resampling and filtering is essential in the case of wave band analysis and is
recommended to homogenize the profiles and facilitate comparisons. For benchmark purposes a
2)
resampling procedure according to the resample function in Matlab® is needed. For other use a linear
model could be used. Depending on purpose there are four possible evenness indices groups to choose
from. The first is the calculation of the International Roughness Index, IRI, described in Annex A
(normative) that should be used in international comparison and benchmark tests, second is calculating
evenness-energy in three different wavelength bands using the bi-octave processing (RMS) described in
Annex C (informative). The third is an alternative method to calculate evenness-energy in three wave
band bands using profile variance (LPV) in Annex D (informative). Finally, the fourth method is to
calculate the range of evenness-variation and deviation using the weighted longitudinal profile (WLP)
described in Annex E (informative). In Annex B, an example code to calculate IRI is presented. The
general process on calculation of evenness indices is illustrated in Figure 2.

Figure 2 — Overview of the calculation process of indices (references to chapter in paranthesis)

2) Matlab® is an example of a suitable product available commercially. This information is given for the
convenience of users of this European Standard and does not constitute an endorsement by CEN of this product.
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6 International Roughness Index (IRI)
6.1 General
The IRI is an index computed from a longitudinal road profile measurement using a virtual response
type system, quarter-car simulation, running at a speed of 80 km/h, see Figure 3. The quarter-car
simulation applied on the digitized road profile calculates the accumulated suspension motions Z and
s
Z in Figure 3 divided by the distance travelled. The description of the IRI calculation is based on [7]:
u
— IRI is computed from a single longitudinal road profile. The acquisition repetition interval should
be no larger than 125 mm for accurate calculations. The required vertical sensor resolution
depends on the evenness level, with finer resolution being needed for smooth roads. A vertical
sensor resolution of 0,5 mm is suitable for all conditions;
— the profile is assumed to have a constant slope between sampled elevation points;
— the profile is smoothed with a moving average whose base length is 250 mm;
— the smoothed profile is filtered using a quarter-car simulation, with specific parameter values, at a
simulated speed of 80 km/h;
— the simulated suspension motion is linearly accumulated and divided by the length of the profile to
yield IRI. Thus, IRI has units of slope, such as millimetres per meter or metres per kilometre.

Key
1 sprung mass m 4 unsprung mass m
s u
2 suspension damping rate c 5 tyre spring rate k
s t
3 suspension spring rate k 6 longitudinal profile Z(x)
s
Z and Z accumulated suspension motions
s u
Figure 3 — Quarter car (virtual response type system)
More details on the method of IRI calculation and sample code are given in Annex A and Annex B.
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6.2 Representation of the obtained results
The IRI can be calculated with a different evaluation length L. For a more detailed analysis of the road
profile data, one can vary the evaluation length L. Therefore, this should be indicated as the first sub
index, e.g. IRI if the length L = 20 m. For the purpose of European benchmarking 100 m evaluation
20
length is recommended and should be denoted IRI .
100
Variations in IRI parameters as shown in Figure 3 or in the simulation speed are beyond the scope of
this document. If, however, for whatever reason the Quarter-car simulation is calculated with other
parameters than those mentioned, it should not be denoted as IRI.
7 Wave band analysis
7.1 General
In order to perform wave band analysis, the pre-processed profile is split into different wave band
limited profiles using filters, see Figure 4. The wave bands are generally selected to represent different
features of ride quality. For example, applying a short wavelength filter can result in an index that
reflects the presence of small undulations in the road surface, which could be more significant at lower
speeds. In contrast, applying a longer wavelength filter can result in an index that reflects the presence
of long wavelength undulations that would be most likely to affect ride quality at higher speeds.
The definition of the wave bands used as well as the characteristics of the filters used to obtain band
limited signals, from the original longitudinal profile shall be reported. How indices are derived from
the band limited signals shall also be defined.

Key
1 pre-processed profile
2 short wavelength filtered profile
3 medium wavelength filtered profile
4 long wavelength filtered profile
Figure 4 — Wave band splitting
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The filters applied to the longitudinal profile are generally either:
— band-pass filters, where wavelengths outside of a defined range are attenuated; or
— high-pass filters, where wavelengths greater than a defined wavelength are attenuated.
The filters used to break the original longitudinal profile into the previously defined bands, should be
carefully chosen in order to introduce as little distortion as possible in the filtered signals, a common
technique in that view is to use digital forward and reverse filtering associated with measured section
extending beyond the profile which is to be assessed.
7.2 Wave band indices
In order to characterize the different wave band filtered profiles two methods including indices are
specified:
— Root Mean Square (RMS) over bi-octave bands (see Annex C);
— Longitudinal profile variance (LPV) over selected wavelengths (see Annex D).
8 Weighted Longitudinal Profile (WLP) analysis
8.1 General
The Weighted Longitudinal Profile (WLP) is the longitudinal profile which has been weighted by a
weighting function in the frequency domain. The weighting function enhances small wavelengths and
decreases large wavelengths in such a way that their respective power contents become measurable
later by the same scale in the spatial domain. Following the weighting of the spectrum, the WLP is
calculated by carrying out the following steps:
— filtering the weighted signal in octave bands,
— multiplying the octave band-filtered signals by pre-factors (which take into account their respective
power distributions to the total power content), and
— adding up the signals to give the WLP.
The WLP is characterized by the standard deviation, σWLP, and the range of variation, ΔWLP.
8.2 Prerequisites
The WLP calculation is based on the pre-processed profile. The pre-processing involves:
— De-trending the raw profile using a linear regression to remove the offset and trend of the signal.
— Resampling by applying a constant interval of 0,1 m, using a linear interpolation algorithm.
— Pre-filtering by applying a high pass filter to attenuate wavelengths in excess of 100 m. The filter
shall be such that the amplitude of wavelengths greater than 150 m are attenuated by at least 50 %.
The filter should not distort the phase of any profile features with wavelengths shorter than 100 m.
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9 Reporting
The calculated evenness index should be reported per an agreed presentation length. In the case of
international benchmarking this should be 100 meter. This should be indicated as a sub-index as
described in Figure 1 and explained in IRI in 6.2. It is recommended to include the following
administrative information:
— geographic position and information about the measured object;
— the lateral position of longitudinal profile, e.g. right or left wheel path. For benchmark purposes this
should be the outermost wheel path;
— distance measured;
— date and time;
— conditions that could affect the result.
More mandatory information can be found in EN 13036-6 and should be included in the reporting.
Finally any deviation from this document, EN 13036-5, should be documented and reported.
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Annex A
(normative)

Calculation of the IRI
A.1 The IRI calculation
The IRI calculation includes two distinct filters: a moving average and a quarter-car model.
A.2 Moving Average Filter
The moving average filter was included for two reasons; to simulate the enveloping behaviour of
pneumatic tyres on motor vehicles and to reduce the sensitivity of the IRI algorithm to the sample
interval, Δ. For a profile that has been sampled at Δ, a moving average smoothing filter is defined by the
summation in (Formula A.1):
ik+−1
1
h i = hj
() ( )
ps p
∑
k
ji=
(A.1)


L
B
k= max1, nint

∆


where
h profile height;
p
h smoothed profile height;
ps
max maximum of two arguments;
nint nearest integer, and
L moving average base length, 250 mm.
B
A.3 The quarter-car simulation parameters defining IRI
The IRI is calculated using the quarter-car simulation. It includes the major dynamic effects that
determine how unevenness causes vibrations in a road vehicle. The masses, springs, and dampers are
defined by the following parameters:
c  = suspension damping rate
s
k  = suspension spring rate
s
k  = tyre spring rate
t
m  = sprung mass (portion of vehicle body mass supported by one wheel)
s
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m  = unsprung mass (mass of wheel, tyre, and half of axle/suspension)
u
To simplify the equations, the parameters are normalized by the sprung mass, m . The following values
s
for the normalized parameters define the IRI set:
c = c /m = 6,0 k = k /m = 653
s s 1 t s
(A.2)
k = k /m = 63,3 µ = m /m = 0,15
2 s s u s
The quarter-car simulation is described by four first-order ordinary differential equations that can be
written in matrix form (Formula A.3).

(A.3)
x Ax+ Bh
ps
where the x, A, and B arrays are defined as follows:
T
 
x= z z z z
s s u u


01 0 0

−−kc k c
22

0 0 0 1
A= (A.4)

k kk+
cc

2 12
− −

µµ µ µ

T

k
1
B= 000

µ


where
h = smoothed profile elevation;
ps
z  = height (vertical position) of the sprung mass;
s
z  = height (vertical position) of the unsprung mass; and
u
x  = array of state variables (i.e. the variable that completely describe the stat of the simulated
system).

Time derivatives are indicated with a dot (e.g. z ). Time is calculated from the longitudinal distance and
s
the simulated speed V, which is defined as 80 km/h.
The IRI is an accumulation of the simulated motion between the sprung and the unsprung masses in the
quarter-car simulation, normalized by the length L of the profile:
LV/
1
 
IRI z− z dt (A.5)
su
∫
L
0
A.4 Solving the differential equation
To solve differential equation such as Formula A.3, one should know the initial values of the state
variables at the starting time. In the standard IRI simulation, the initial values influence the quarter car
response for about 20 m. In order to estimate the initial values, z and z should be set to match the
s u
 
height of the first profile point and z and z should be set to match the average change in profile
s u
15
=
=

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height per secon
...