Results of a UK trial

st and 2nd generation
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results of a UK
presentation
trial
Presented by Name Here
Job Title - Date
Brian Ferne, TRL
National Pavement
Evaluation Conference
Virginia Tech
15-18 September 2014
Acknowledgements to co-authors:
Stefano Drusin, ANAS, Italy
Susanne Baltzer, DRD, Denmark
TRL colleagues
Acknowledgement of support from:
English Highways Agency
ANAS, Italy
Danish Road Directorate
Page  2
Contents
1
Introduction
2
Purpose of trials and methodlogy
3
Trial site and procedure
4
Results of trials
5
Interim conclusions
Page  3
Contents
1
Introduction
2
Purpose of trials and methodolgy
3
Trial site and procedure
4
Results of trials
5
Interim conclusions
Page  4
Background to network structural
surveys in England
 Until 2000 walking-speed Deflectograph surveys
were needed to deliver this data
- Safety issues
- Disruptive to traffic
- Expensive per km
 15 machines needed for whole network
 Key Drivers for Traffic Speed Deflectometer
Surveys
 TSD measures vertical deflection velocity
 Velocity highly correlated to maximum
deflection
 Deflection can be used with construction and
traffic to estimate structural condition
 One TSD covers whole network
TSD – History in England
- Worldwide review identified device
- 2nd prototype purchased for HA 2005
- Developed into surveying tool 2006-2009
- Routine surveys with HA TSD from 2010
under TRASS contracts
 TRASS surveys provide:
- An efficient economical survey
- Without interfering with traffic flow
- Over the whole network, every one or two
years
 Programme of continuous improvement
- 2nd Generation machines now under
assessment
First Generation TSD’s – DRD, Denmark and HA,
England
Second generation TSD’s – ANAS, Italy, IBDiM, Poland, etc
Page  7
Contents
1
Introduction
2
Purpose of trials and methodology
3
Trial site and procedure
4
Results of trials
5
Interim conclusions
Page  8
Purpose of comparative trial
To assess relative performance of first and second generation
TSD’s in terms of:
•
•
•
•
Measured deflection response
Short-term repeatability of measurements
Stability of measurements, i.e. long-term repeatability
Methods of calibration
And therefore provide guidance to the English Highways
Agency (HA) on the potential benefits of upgrading their TSD
Page  9
Methodology
Controlled side-by-side tests of 1st and 2nd generation machines
 Calibration methods – on suitable sites
 On closed instrumented track - MIRA
 On well-characterised section of road network
 1st generation machines = HA TSD and DRD TSD
 2nd generation machine = ANAS TSD
 ANAS and DRI TSD measured right hand wheelpath
 HA’s TSD measured left hand wheelpath
Page  10
Contents
1
Introduction
2
Purpose of trials
3
Trial site and procedure
4
Results of trials
5
Interim conclusions
Page  11
MIRA proving ground - Nuneaton, Warwickshire
Research Pavement
Research Pavement thickness profile
– nearside wheelpath
TT3
Page  13
TT1
TT2
TT4
Deflection measurements on MIRA test sections
TT3
TSD slope
At 300mm
offset
TT1
TT2
TT4
FWD Do
Deflectograph
Return
UK Comparative trials at MIRA
 October 2013
 Closed instrumented site – MIRA HA test sections
 Two 1st generation TSD’s
 HA TSD with sensors at 100, 300 and 756mm
 DRD TSD with sensors at 100, 200 and 300mm
 One 2nd generation TSD
 ANAS TSD with sensors at 100, 200, 300, 600, 900 and
1500mm
 However…………
Page  15
UK Comparative trials October 2013
 October 2013
 Closed instrumented site – MIRA HA test sections
 Two 1st generation TSD’s
 HA TSD with sensors at 100, 300 and 756mm – LH WP
 DRD TSD with sensors at 100, 200 and 300mm – RH WP
 One 2nd generation TSD
 ANAS TSD with sensors at 100, 200, 300, 600, 900 and
1500mm – RH WP
 Poor weather
 Slow height sensor failure on UK TSD
Page  16
Methodology 1 for comparing right and left hand
sensors
1/4Mile sign
Lane 1
1000m
Direction of traffic
Odometer test section
Lane 2
Round the bend
Right wheel path
TRL Instrumented test section
MP 5
MP 4
147m
Survey end
Approx. 200m
TT6
DRI
MP 3
MP 2
ANAS
TRL
149.6m
89.9m
69.3m
69.4m
69.8m
TT5
TT4
TT2
TT1
TT3
Lane 2
Round the bend
Lane 1
MP 1
Survey start
500m
Figure not to scale
595m
Methodology 2 for comparing right and left hand
sensors
TRL TSD travelling in CLOACKWISE DIRECTION
1/4Mile sign
Lane 1
Lane 2
TRL TSD to stay in Lane 2 (cones will be placed to indicate start and end)
Lane 2
MP 5
TRL Instrumented test section
MP 4
147m
Page  17
149.6m
MP 3
89.9m
MP 2
69.3m
69.4m
TRL
69.8m
MP 1
Lane 1
Figure not to scale
Contents
1
Introduction
2
Purpose of trials
3
Trial site and equipment
4
Some early results of trials
5
Interim conclusions
Page  18
MIRA Trials ANAS TSD P300 sensor 4 runs at 70 km/h
TT3
Strong
TT1
Weak
TSD
slope
TT2
Intermediate
TT4
Existing
Distance (m)
Page  19
MIRA Trials DRD TSD P300 sensor 4 runs at 70 km/h
Page  20
MIRA Trials HA TSD P300 sensor 3 runs at 70 km/h
Page  21
MIRA trials Averages of all three TSD’s P300 sensor
Page  22
Laser set-up – calibration
β
α
venc
ANAS TSD – variation in calibration of each sensor through trial period
Page  24
Effect of variation in calibration angles on estimates of SCI300
Page  26
MIRA site - ANAS TSD – all sensors
200mm offset
1500mm offset
Page  28
MIRA site - ANAS TSD – all sensors
TT2
TT1
200mm offset
1500mm offset
Page  29
Examples of simple modelling of deflection and deflection slope
under load.
5.00E-02
0.00E+00
Deflection (mm)
-5.00E-02 0
2000
4000
6000
8000
10000
12000
-1.00E-01
Easp=1550MPa
-1.50E-01
Easp=3100MPa
-2.00E-01
Easp=6200MPa
-2.50E-01
-3.00E-01
-3.50E-01
-4.00E-01
Distance (mm)
2.50E-04
2.00E-04
Slope
1.50E-04
1.00E-04
5.00E-05
Easp=1550MPa
0.00E+00
Easp=3100MPa
-5.00E-05 0
-1.00E-04
-1.50E-04
2000
4000
6000
-2.00E-04
-2.50E-04
Distance (mm)
8000
10000
12000
Easp=6200MPa
Examples of simple modelling of deflection and deflection slope
under load.
5.00E-02
0.00E+00
Deflection (mm)
-5.00E-02 0
2000
4000
6000
8000
10000
12000
-1.00E-01
Easp=1550MPa
-1.50E-01
Easp=3100MPa
-2.00E-01
Easp=6200MPa
-2.50E-01
-3.00E-01
-3.50E-01
-4.00E-01
Distance (mm)
2.50E-04
2.00E-04
Slope
1.50E-04
1.00E-04
5.00E-05
Easp=1550MPa
0.00E+00
Easp=3100MPa
-5.00E-05 0
-1.00E-04
-1.50E-04
2000
4000
6000
-2.00E-04
-2.50E-04
Distance (mm)
8000
10000
12000
Easp=6200MPa
ANAS vs DRI vs TRL slopes vs offset – Section TT1
Page  32
ANAS vs DRI vs TRL slopes vs offset – Section TT2
Page  33
Contents
1
Introduction
2
Purpose of trials
3
Trial site and equipment
4
Results of trials
5
Interim conclusions
Page  34
Summary and conclusions
Preliminary results from the 2013 TRL MIRA comparative
trial have suggested that:
• First and second generation TSD’s can measure very
similar longitudinal strength profiles to each other and to
other deflection devices
• Short term repeatability is good
• Long term repeatability is not yet proven although some
available calibration methods for second generation
machines appear to offer promise.
• Robust methodology for calibrating and quality auditing
surveys is essential if meaningful measurements are to
be collected.
Page  35
TRASS1&2 Summary
 The HA TSD was successfully
developed into a system capable
of delivering routine network
level surveys
 Over 18000km of structural
condition information was
collected by TRASS1 and
TRASS2
 Robust QA regime established
 HA Managing Agents could be
provided with indicator of
network level structural
condition
 TRASS3 started last week
Thank you
Presented by Brian Ferne
17 September 2014
Tel: 01344 770668
Email: [email protected]
Page  37

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