Insert the title of your presentation here Hpw do 1 st and 2 nd generation TSD s compare results of a UK 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 2 3 4 5 Introduction Purpose of trials and methodlogy Trial site and procedure Results of trials Interim conclusions Page 3
Contents 1 2 3 4 5 Introduction Purpose of trials and methodolgy Trial site and procedure Results of trials 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 - 2 nd 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 - 2 nd 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 2 3 4 5 Introduction Purpose of trials and methodology Trial site and procedure Results of trials 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 1 st and 2 nd generation machines Calibration methods on suitable sites On closed instrumented track - MIRA On well-characterised section of road network 1 st generation machines = HA TSD and DRD TSD 2 nd generation machine = ANAS TSD ANAS and DRI TSD measured right hand wheelpath HA s TSD measured left hand wheelpath Page 10
Contents 1 2 3 4 5 Introduction Purpose of trials Trial site and procedure Results of trials Interim conclusions Page 11
MIRA proving ground - Nuneaton, Warwickshire Research Pavement
Research Pavement thickness profile nearside wheelpath TT3 TT1 TT2 TT4 Page 13
Deflection measurements on MIRA test sections TT3 TT1 TT2 TT4 TSD slope At 300mm offset FWD Do Deflectograph Return
UK Comparative trials at MIRA October 2013 Closed instrumented site MIRA HA test sections Two 1 st generation TSD s HA TSD with sensors at 100, 300 and 756mm DRD TSD with sensors at 100, 200 and 300mm One 2 nd generation TSD ANAS TSD with sensors at 100, 200, 300, 600, 900 and 1500mm However Page 15
UK Comparative trials October 2013 October 2013 Page 16 Closed instrumented site MIRA HA test sections Two 1 st 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 2 nd 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
Methodology 1 for comparing right and left hand sensors 1/4Mile sign 1000m Lane 1 Direction of traffic Odometer test section Round the bend Lane 2 Right wheel path TRL Instrumented test section MP 5 MP 4 MP 3 DRI MP 2 ANAS TRL MP 1 Lane 2 Lane 1 Round the bend Survey end Approx. 200m 147m TT6 149.6m TT5 89.9m TT4 595m 69.3m TT2 69.4m TT1 69.8m TT3 Survey start 500m Figure not to scale 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 MP 3 MP 2 TRL MP 1 Lane 1 147m 149.6m 89.9m 69.3m 69.4m 69.8m Figure not to scale Page 17
Contents 1 2 3 4 5 Introduction Purpose of trials Trial site and equipment Some early results of trials Interim conclusions Page 18
MIRA Trials ANAS TSD P300 sensor 4 runs at 70 km/h TT3 Strong TT1 Weak TT2 Intermediate TSD slope TT4 Existing Page 19 Distance (m)
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 v enc
Page 24 ANAS TSD variation in calibration of each sensor through trial period
Page 26 Effect of variation in calibration angles on estimates of SCI300
MIRA site - ANAS TSD all sensors 200mm offset 1500mm offset Page 28
MIRA site - ANAS TSD all sensors TT1 TT2 200mm offset 1500mm offset Page 29
Examples of simple modelling of deflection and deflection slope under load. 5.00E-02 0.00E+00-5.00E-02 0 2000 4000 6000 8000 10000 12000 Deflection (mm) -1.00E-01-1.50E-01-2.00E-01-2.50E-01 Easp=1550MPa Easp=3100MPa Easp=6200MPa -3.00E-01-3.50E-01-4.00E-01 Distance (mm) 2.50E-04 2.00E-04 1.50E-04 1.00E-04 5.00E-05 Easp=1550MPa Slope 0.00E+00-5.00E-05 0 2000 4000 6000 8000 10000 12000 Easp=3100MPa Easp=6200MPa -1.00E-04-1.50E-04-2.00E-04-2.50E-04 Distance (mm)
Examples of simple modelling of deflection and deflection slope under load. 5.00E-02 0.00E+00-5.00E-02 0 2000 4000 6000 8000 10000 12000 Deflection (mm) -1.00E-01-1.50E-01-2.00E-01-2.50E-01 Easp=1550MPa Easp=3100MPa Easp=6200MPa -3.00E-01-3.50E-01-4.00E-01 Distance (mm) 2.50E-04 2.00E-04 1.50E-04 1.00E-04 5.00E-05 Easp=1550MPa Slope 0.00E+00-5.00E-05 0 2000 4000 6000 8000 10000 12000 Easp=3100MPa Easp=6200MPa -1.00E-04-1.50E-04-2.00E-04-2.50E-04 Distance (mm)
Page 32 ANAS vs DRI vs TRL slopes vs offset Section TT1
Page 33 ANAS vs DRI vs TRL slopes vs offset Section TT2
Contents 1 2 3 4 5 Introduction Purpose of trials Trial site and equipment Results of trials 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: bferne@trl.co.uk Page 37