The sensitivity of repeated profile measurements to pavement unevenness and surface conditions

Transcription

1 CONTROL ENGINEERING The sensitivity of repeated profile measurements to pavement unevenness and surface conditions ENEA SOGNO and MICHELE MORI Prague,

2 Summary The company Business sectors Accreditation to ISO-IEC The experience with road profilers Surveys on reference test sites Analysis Technical results Final remarks 2

3 The company Sineco S.p.A. is an Italian company which provides extended engineering services to infrastructure managers worldwide. It belongs to the Gavio Group. CONSTRUCTION MOTORWAY CONCESSIONS ENGINEERING ENERGY TRANSPORTS, PORTS AND LOGISTICS SHIPBUILDING TECHNOLOGY SERVICES AND OTHER 3

4 The company Since 1987, Sineco S.p.A. has been operating in the field of engineering, with special reference to the control and planning of maintenance interventions for transport infrastructures More than 1,000 major works monitoring Over 5,000 Km of road pavement surveys per years 4

5 Business sectors Airports Roads&Motorways Railways Enviroment Architectural Heritage 5

6 Accreditation to ISO-IEC The company fits the accreditation process by which the technical competence of the laboratory is yearly certified with respect to the management system requirements in ISO/IEC 17025:2005, properly meeting the principles of ISO 9001:2008 and being aligned with its pertinent requirements. Continuous runs and tests to control the efficiency of the surveying machines Periodic checks for the consistency of acquired data (repeatability, uncertainness, tolerance) 6

7 The experience with road profilers Sineco holds several high-performance surveying machines on which different, extremely precise laser sensors have been mounted in order to collect information about longitudinal and transverse profiles of the pavement surface. Three machines have been provided with profilers that meet class 1 requirements according to the E ASTM standard (longitudinal sampling less than or equal to 25 mm, vertical measurement resolution less than or equal to 0,1 mm). These are the Pave- Scanner, the ARAN (Automatic Road Analyzer) and the new generation SCRIM+ (Sideway force Coefficient Routine Investigation Machine and Texture meter). Another machine mounts class 2 profilers on both pathways, which means that it can perform surveys with longitudinal sampling greater than 25 mm to 150 mm and vertical measurement resolution greater than 0,1 mm to 0,2 mm. This is a 1 st generation SCRIM+. Two LMM scanner systems (Laser Mobile Mapping) have then the capability of realizing a 3D representation of significant distances around them from point clouds post-processing, thus offering information even on vertical and sideway slopes of any targeted surface with an acceptable resolution for infrastructure managers. One of them has been coupled with the LCMS to realize the ultimate laser technology in the field of ground surveying. All these machines constantly move in the field for operation purposes. Besides, most of them often goes under the supervision of technicians and engineers for the evaluation of the consistency of data they acquire. 7

8 Surveys on reference test sites Periodic checks of laser technologies mainly occur in test sites having well known characteristics and being suitable to highlight eventual failures in system operations. Among others, an about 3.6 km long AC surfaced test track allowed in the time to appreciate the measure by which the distress level in the pavement surface may affect the determination of longitudinal and transverse profiles, and the roughness. N End Section 3 Wide, interconnected cracks and potholes in the pavement surface Target #1 Section 2 Minor, unconnected cracks in the pavement surface Target #2 Section 1 No cracks, new pavement Start 8

9 Surveys on reference test sites Cracks resulting from Pave- Scanner system (after processing, GIS environment): <6mm wide green Section 1 low Section 3 high 6 25mm wide yellow >25mm wide red Total amount of cracks Section 2 medium 9

10 Surveys on reference test sites Section 1 10

11 Surveys on reference test sites Section 2 11

12 Surveys on reference test sites Section 3 12

13 Surveys on reference test sites Targets #1 and #2 are located, respectively, on the left wheel-path in the North direction next to the frontier between section 1 and section 2, and on the right wheel-path in the South direction in section 2. Target #1 Target #2 13

14 Surveys on reference test sites Lanes in the North and the South direction are about 3,2 meters wide. This is convenient for the evaluation of profiles due to well definite outer wheel-paths which allow comparisons across the entire width of the carriageway. 3,20 mt 3,20 mt About 50 cm wide phoenomena Right wheel-path shows important rutting and cracking 14

15 Analysis It is well known that the transverse position in the carriageway of a vehicle equipped with laser sensors may influence the shape of the determined longitudinal profiles. The potential error depends on the distress level in the pavement surface. According to that, preliminary evaluations of longitudinal profiles at 12,5 cm offset positions from the center of the lane in the North direction have been performed based on Pave-Scanner data information. Right wheel-path profiles: sensitivity to distress in the pavement surface at different distances from the center of the lane 15

16 Analysis Left wheel-path profiles: sensitivity to distress in the pavement surface at different distance from the center of the lane At least two occurrences may be appointed: right and left profiles strongly change their amplitude due to heavy distress (section 3), and whatever shape variations may not be perceived independently of transverse position in both wheel-pats. 16

17 Analysis Right wheelpath profiles per km of lane 17

18 Analysis Left wheelpath profiles per km of lane 18

19 Analysis Repeatability and consistency of profiles acquired at the speed of 60 km/h have been searched looking at their shapes and amplitudes, while the efficiency of surveys, that is, the potential for detecting targets #1 and #2, has been evaluated for all surveying technologies from I.R.I. (International Roughness Index) distribution along the sections. Section 1 IRI avg 1,22 Section 1 IRI avg 1,67 Section 1 IRI avg 3,32 19

20 Analysis Target 2 North direction Class1_pro1 Class1_pro2 Class1_pro3 IRI SX IRI DX IRI SX IRI DX IRI SX IRI DX Media 1,17 1,38 1,11 1,55 1,09 1,74 Km 1 Dev.st. 0,77 0,55 0,59 0,73 0,59 0,81 CV 0,66 0,39 0,53 0,47 0,54 0,47 Media 1,63 1,54 1,56 1,65 1,57 1,85 Km 2 Dev.st. 0,70 0,76 0,67 0,80 0,66 1,05 CV 0,43 0,49 0,43 0,48 0,42 0,57 Media 2,43 3,00 2,52 3,54 3,12 4,43 Km 3 Dev.st. 1,60 2,24 1,78 3,42 2,35 4,18 CV 0,66 0,75 0,71 0,97 0,75 0,94 20

21 Analysis The influence which the distress level in the pavement surface produces onto unevenness assessment has been analyzed also by means of power spectral density functions. This is due to the uncertainty associated to I.R.I. growth without the awareness whether specific wavelengths being independent of surface distress exist or not. The PSD function has then been computed for the meters offset profile on the entire lane, north direction, with the intention of recognizing different behaviors of the surveying vehicle along with the single sections. Section 1 PSD elevation Major wavelenghts between 10 and 30 mt offset 21

22 Analysis Section 1 PSD slope (log scale mt offset 22

23 Analysis Section 2 PSD slope (log scale mt offset 23

24 Analysis Section 3 PSD slope (log scale mt offset 24

25 Analysis Focusing on yearly test repetitions to assess the effect of traffic on profiles collected at the same transverse line of the lane brought to understand the measure by which time affects measurements, which was expected, but also to highlight that surveys made in the same time with class 1 profilers are strictly repeatable. Series Q1 Q3 IQR MAX MIN MAX-MIN pro0_sx -0,44 0,40 0,84 3,87-2,27 6,14 pro0_dx -0,39 0,37 0,76 3,41-2,88 6,29 pro1_sx -0,46 0,45 0,91 2,78-3,99 6,77 pro1_dx -0,48 0,45 0,93 3,12-3,70 6,82 15,00% 9,33% I.Q.R. (Inter Quartile Range) of profiles collected in the same standard conditions widened after 1 year from previous survey of 15%, as a consequence of distress evolution in section 3. The amplitude range has increased in the same time interval of about 10%. Rep1 Rep2 Rep3 Rep4 Rep5 Rep6 Mean RMS CV IRI_dx 1,08 1,76 1,73 1,63 1,68 1,68 1,60 0,26 16% IRI_sx 1,67 1,03 1,06 1,00 1,00 1,03 1,13 0,26 23% IRI_avg 1,37 1,40 1,40 1,32 1,34 1,36 1,36 0,03 2% Results from 6 repetitions carried out in the 1 st km of the test track show I.R.I. values very similar to those calculated 1 year before on the same portion of the lane and constant average indicators which means that the acquired profiles do not vary significantly. 25

26 Technical results Laser sensors provide information which are sensitive to the state of health of the pavement surface. According to this, it is important to keep the material and also the distress of the pavement surface controlled while surveying for comparison purposes

27 Technical results Distress affects measurements when laser sensors move in the direction of the pathway, while varying transversal positions is responsible of slightly changing the amplitude of profiles but it does not modify their shape. Cracks and potholes, bad pavement conditions => unevenness No cracks, good pavement conditions => good roughness 27

28 Technical results Good pavement surface good I.R.I. (green <2 mm/m, yellow 2 6mm/m) 28

29 Technical results Cracks in the pavement surface higher I.R.I.(green<2mm/m,yellow2 6mm/m,red>6mm/m) 29

30 Technical results Cracks and potholes higher I.R.I.(green<2mm/m,yellow2 6mm/m,red>6mm/m) 30

31 Technical results Surface distress produces effects both on the amplitude and (minor) on the wavelength characterizing unevenness, as resulted from PSD functions calculations. Changing transverse positions as the reference for longitudinal profiles has been directly allowed by Pave-Scanner surveys and has been responsible of no significant variations of the amplitude of collected profiles, nor their shape did change. The existence of targets may be clearly detected if they are isolated, or they occur in good conditions pathways. Consistency of data from road profilers can be assessed only in standard, controlled surveying conditions. Narrow lanes and fixed markings make it possible the get the uniformity of surveying conditions. The effect of traffic and surface ageing can be investigated with high-efficiency laser technologies. The control of the efficiency of laser technologies allows Sineco to get the certainty of repeatability assessments on profile surveys. 31

32 Final remarks Checking the efficiency of laser technologies is recommended only on good pavements The importance of paths along the surveyed lane is not comparable to the distress level in the pavement surface Potential unevenness revealed by profilers is independent of surface distress Surveying conditions affect the tolerance associated to profile data Researchers may help private companies and operators to properly manage information 32

33 Prague, 20 th October 2016 Thank you for your attention 33

34 CONTROL ENGINEERING The sensitivity of repeated profile measurements to pavement unevenness and surface conditions ENEA SOGNO and MICHELE MORI Prague,