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S. Lakui, D. Bri, V. Tkalevi Lakui: Analysis of Vehicle Vibrations New Approach to Rating Pavement Condition of Urban Roads

486 Promet Trafc&Transportation, Vol. 23, 2011, No. 6, 485-494

road-rail intersections and track pavements, in somecases complete reconstruction is required. In this ar-ticle several cases of car vibrations have been consid-ered in the investigation:

on urban roads with poor pavement structure and

large trafc volume (before and after reconstruc-

tion), Zagreb Avenue, Case A; on rail-road intersections; ubieva-Zvonimirova

intersection (direction: South-North); Drieva-Vukovarska intersection (direction: South-North);Savska-Vukovarska intersection (direction: East-West); Case B;

on urban roads with tram tracks incorporated intheir composition (tram tracks are paved by differ-ent materials: cobblestone and precast concreteplates), Hanueva street, Case C.For better correlation between road surface and ve-

hicle vibrations measurement of road surface rough-

ness was also carried out before and after reconstruc-tion of the observed test sections (Case A to C). Thismethod gives best insight into the impact of recon-struction on the level of ride comfort and safety thatdepends on road surface roughness and is directlycorrelated to vehicle vibrations.

Suggested and analysed urban road pavementcondition determination technology provided a simpleroad survey (vehicle vibration measurements) as avaluable source of information for trafc and civil engi-neers on road maintenance requirements.

2. EXPERIMENTAL METHODAND CONDITIONS

2.1 Vibrations measurement system

The testing platform used in this study was a per-sonal car; OPEL Vectra B1.8, 1.6V (2002). The carwas equipped with standard tyres. To collect, record,and analyze the data, a measurement system was de-signed and installed in the vehicle. It consisted of:

Accelerometer A1, Brel & Kjr type 4508B1, 10mV/g, 0.1 Hz 8 kHz;

Accelerometer A2, Brel & Kjr type 4508B, 100mV/g, 0.3 Hz 8 kHz;

Battery-powered Data Acquisition Unit Brel &Kjr PULSE;

Portable computer for data recordings and post-analysis;

Voice recorder and video camera.The two accelerometers for vibration measurement

were installed at an authorized dealer in Zagreb (OpelAutoWill). The rst accelerometer (A1) was mountedon the front right wheel holder (Figure 1) and the sec-ond accelerometer (A2) was mounted to the chassis

immediately next to the passenger seat (Figure 2). Vi-

brations in the vertical direction (perpendicular to the

road surface) were recorded using a battery-poweredmulti-channel Brel & Kjr PULSE analyzer and theTime Data Recorder program (Figure 3). Informationregarding some specic qualities during the measure-ment were recorded by means of a voice dictaphone

and a video camera.

Figure 1 - Accelerometer A1 on the front wheel holder

A2

Figure 2 - Accelerometer A2 on the vehicle chassis

Figure 3 - Measuring equipment in the vehicle

Figure 4 - Greenwood LaserProf device

2.2 Measurement of road surface roughness

For the research into how much the road surface af-fects the vehicle vibrations and driving comfort, mea-surements of the road surface roughness have beenrecorded. It is well known that the construction or re-

construction of a pavement structure cannot achieve aperfectly even driving surface. However, the permitteddeviations of the evenness of a driving surface are de-

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3.2 Effect of rail-road intersection (Case B)

Driving through the intersection of road and tramor railways tracks (rail-road intersection) alwayscauses uncomfortable and unpleasant driving, aswell as high car vibrations. Research was conductedon several high-frequency intersections in Zagreb,where there is a large trafc load, both by road ve -hicles and by the vehicles on tracks. The measure-ment of IRI parameters on the crossings, in which carvibrations were measured, is presented in Table 1. As

can be seen on the observed intersection the IRI pa-rameter was measured before and after reconstruc-tion. Vehicle vibrations on all rail-road intersectionshave been measured with constant vehicle speed of40km/h. The maximum value of vibration is the re-sult of vehicles crossing over the rails but dependslargely on the track pavement material. The consid -ered intersections had different materials for trackclosure (pavement). The type of rail-road intersectionpavement, before and after reconstruction, is pre-sented in Table 2.

Before reconstruction

Vibrations

[m/s

]2

Time [s]

0 20 40 60 80 100 120

40

20

0

-20

-40

After reconstruction

Vibrations

[m/s

]2

Time [s]

0 20 40 60 80 100

40

20

0

-20

-40

Graph 1 - Time profile of car wheel holder vibrations ( 40 m/s )2

100

60

80

20

40

0

Vibrations

[mm

/s

]

0 20 40 60 80 100 120

Time [s]

75 mm/s, 34 s Before reconstruction

1 sectionst

2 sectionnd

100

60

80

20

40

0

Vibrations

[mm

/s

]

0 20 40 60 80 100 120

Time [s]

15.3 mm/s

Before reconstruction

Graph 2 - Car wheel holder and car frame vibrations before reconstruction (Zagreb Avenue)

Graph 3 - Car wheel holder and car frame vibrations after reconstruction (Zagreb Avenue)

100

60

80

20

40

0

Vibrat

ions

[mm

/s

]

0 20 40 60 80 100

Time [s]


21 mm/s, 37 s

100

60

80

20

40

0

Vibrat

ions

[mm

/s

]

0 20 40 60 80 100

Time [s]


8.3 mm/s, 37 s

Table 2 - Type of rail-road intersection pavement

Rail-road intersectionType of track pavement

Before reconstruction After reconstruction

ubieva Zvonimirova cobblestone asphalt

Vukovarska - Drieva concrete plates asphalt

Savska Vukovarska asphalt asphalt

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Promet Trafc&Transportation, Vol. 23, 2011, No. 6, 485-494 489


Graph 4 - Vehicle vibrations on ubi eva-Zvonimirova intersection (before reconstruction)

200

120

160

40

80

0Car

whee

lvib

rations

[mm

/s

]

0 4 8 12 16 20 24 28 32

Time [s]

200

120

160

40

80

0Car

framevib

rations

[mm

/s

]

0 4 8 12 16 20 24 28 32

Time [s]

Graph 5 - Vehicle vibrations on ubi eva-Zvonimirova intersection (after reconstruction)

200

120

160

40

80

0Wheel

holder

vibra

tions

[mm/s]

0 1 2 3 4 5 6 7 8 9 10 11 12 0 1 2 3 4 5 6 7 8 9 10 11 12

Time [s]

200

120

160

40

80

0Car

frame

vibrations

[mm/s]

Time [s]

Graph 6 - Vehicle vibrations on Vukovarska-Dri eva intersection (before reconstruction)

200

120

160

40

80

0Wheel

holder

vibrations

[mm/s]

0 4 8 12 16 20 24 28 32

Time [s]

200

120

160

40

80

0Car

frame

vibrations

[mm/s]

0 4 8 12 16 20 24 28 32

Time [s]

Graph - Vehicle vibrations on Vukovarska intersection (after reconstruction)7 -Drieva

200

120

160

40

80

0Wheel

holder

vibrations[m

m/s]

0 1 2 3 4 5 6 7 8 9 10 11 12 0 1 2 3 4 5 6 7 8 9 10 11 12

Time [s]

200

120

160

40

80

0Car

frame

vibrations

[mm/s]

Time [s]

The measured vehicle vibrations on ubieva-

Zvonimirova intersection (before and after reconstruc-tion) are presented in Graphs 4 and 5. The maximum

values of wheel holder vibrations were 180mm/s

(before reconstruction) and 78mm/s (after recon-struction). Maximum car frame vibrations were up to

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48mm/s (before reconstruction) and 30.5mm/s (afterreconstruction).

The measured vehicle vibrations on Vukovarska-Drieva intersection (before and after reconstruction)are presented in Graphs 6 and 7. The maximum val-ues of wheel holder vibrations were 145mm/s (beforereconstruction) and 35mm/s (after reconstruction).Maximum car frame vibrations were up to 32.5mm/s(before reconstruction) and 22mm/s (after recon-struction).

The measured vehicle vibrations on Savska-Vuk-ovarska intersection (before and after reconstruction)are presented in Graphs 8 and 9. The maximum val-ues of wheel holder vibrations were 84.7mm/s (beforereconstruction) and 35mm/s (after reconstruction).

Maximum car frame vibrations were up to 41.2mm/s(before reconstruction) and 12.1mm/s (after recon-struction).

3.3 Effect of tram track pavement (Case C)

It is a well known fact that on those parts whererail and road vehicles use the same trafc surface be-cause of narrow trafc corridors (the very centre of thecity), the rail structure is within the composition of thepavement structure, as shown in Figure 16. In such cas-es, tracks are being paved by certain materials. Con-

crete ller and nal asphalt layer (the same as on roadtrafc route) are frequently used on rail-road intersec-

tion where signicant dynamic loads are present dueto heavy road freight trafc. On other parts of railway

tracks, for the purpose of rail structure maintenance,mounting/dismounting elements for track pavementcan be found in frequent use. In the paper, two suchcases have been studied, track pavement with cobble-stones and track pavement with concrete plates. Thepaper analyses tramway track in Ozaljska street be-fore and after reconstruction. The IRI measurementshowed that in pavements with cobblestones the IRIis 9.28m/km (before reconstruction), while in trackpavements with concrete plates, the IRI is 3.63m/km(after reconstruction).

While driving over tram tracks, which are embed-ded in cobblestones, constantly increased vibrations

were measured with a maximum of 98mm/s for wheelvibrations and 40mm/s for car frame vibrations, Graph10. While driving over the tram track, which is embed-ded in concrete plates, considerably smaller wheel vi-brations were measured (maximum 39mm/s), and thecar frame vibrations were not higher than 10mm/s,Graph 11.

4. DISCUSSION

In order to make relations between the parame-ters of pavement roughness (IRI) and the measured

vehicle vibrations, the average vibrations have beencalculated rst. As mentioned before, the two sections

Graph 8 - Vehicle vibrations on Savska-Vukovarska intersection (before reconstruction)

200

120

160

40

80

0Wheel

holderv

ibrations

[mm/s]

0 4 8 12 16 20 24 28 32

Time [s]

200

120

160

40

80

0Car

frame

vib

rations

[mm/s]

0 4 8 12 16 20 24 28 32

Time [s]

Graph 9 - Vehicle vibrations on Savska-Vukovarska intersection (after reconstruction)

200

120

160

40

80

0Wheel

holder

vibrati

ons

[mm/s]

0 1 2 3 4 5 6 7 8 9 10 11 12 0 1 2 3 4 5 6 7 8 9 10 11 12

Time [s]

200

120

160

40

80

0Car

frame

vibrations

[mm/s]

Time [s]

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Promet Trafc&Transportation, Vol. 23, 2011, No. 6, 485-494 491


of the Zagreb Avenue have been taken into accountbefore the reconstruction with respect to IRI. This factis best illustrated in Graph 2, where the different val-ues of measured vibrations can be observed. On therst section (from 0 to 48sec) where IRI parametermeasures 3.28m/km, the average vibrations on thewheel holder measure 21.2mm/s while vibrations onthe car chassis measure 6.1mm/s. On the secondsection (from 48 to 112sec) where IRI parameter

measures 2.18m/km the average vibrations on thewheel holder measure 12.7mm/s while vibrations on

the car chassis measure 4.5mm/s. After completereconstruction of the Zagreb Avenue, the IRI param-eter (on both sections) measured 1.23m/km and theaverage of the wheel holder vibrations was 7.6mm/s,and of the car chassis 3.5mm/s. The results of theseanalyses are shown in Table 3. For the purpose of ac-curate denition of relations between the parametersof pavement evenness (IRI) and the vehicle vibra-tions, a correlation has been prepared on the basis

of the stated quantities. The results of this analysisare shown in Graph 12.

Figure 5 - Survey of tram track embedded in road surface

Graph 10 - Vehicle vibrations on tram track pavement with cobblestones

100 100

60 60

80 80

20 20

40 40

0 0Wheel

holder

vibrations

[mm/s]

0 2 4 6 8 10 12 14 16 0 2 4 6 8 10 12 14 16

Time [s]

Car

frame

vibrations

[mm/s]

Time [s]

Graph 11 - Vehicle vibrations on tram track pavement with concrete plates

100 100

60 60

80 80

20 20

40 40

0 0Wheel

holder

vibrations

[mm/s]

0 4 8 12 16 20 24 28 32 0 4 8 12 16 20 24 28 32

Time [s]

Car

frame

vibrations

[mm/s]

Time [s]

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