Ride Quality Specifications - Smoothing Out Pavements

1. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Ride Quality Specifications - Smoothing Out Pavements Richard Wix

2. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Outcomes of Presentation What is ride quality and how does it relate to road roughness? How is ride quality measured? How can a basic understanding of IRI lead to a road with a smoother ride?

3. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Why is Ride Quality of Importance? Reduces dynamic loading Increases life expectancy Decreases road user costs Increases user satisfaction SRAs implementing Ride Quality testing for rehab and new construction

4. www.arrb.com.au Advancing safety and efficiency in transport through knowledge What is Ride Quality? �the level of ride comfort experienced by the occupants of a vehicle as it traverses the pavement� dependent on vertical acceleration experienced by occupants acceleration attributable to roughness

5. www.arrb.com.au Advancing safety and efficiency in transport through knowledge What is Roughness? �a condition parameter which characterises deviations from the intended longitudinal profile of a road surface with characteristic dimensions that affect vehicle dynamics... ride quality and dynamic pavement loading� (Austroads 2001) a lack of smoothness

6. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Roughness Measurement in Australia In 1970s ARRB in conjunction with SRAs developed the NAASRA roughness meter Response Type Road Roughness Measurement System (RTRRMS) Must be calibrated

7. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Inertial Laser Profiler Introduced in Australia in the late 1980s to calibrate NAASRA meter Measurements are independent of vehicle dynamics Combines the outputs from a laser and accelerometer to give profile

8. www.arrb.com.au Advancing safety and efficiency in transport through knowledge IRI - �What is it?�

9. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Roughness is ��?

10. www.arrb.com.au Advancing safety and efficiency in transport through knowledge IRI Gain Response

11. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Things to Keep in Mind When Smoothing out Pavements Steps and construction joints Dips, humps and bumps Keeping it (the road surface) clean Site location and delineation Providing sufficient lead-in and lead-out

12. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Steps �a change in height that occurs at a discrete point in the pavement� (Austroads 2002) short duration defect often occur at a bridge abutment or termination of overlay

13. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Effect of Step Height on IRI

14. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Construction Joints

15. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Avoiding Steps and Construction Joints Utilise a continuous paving technique to avoid any discontinuity When placing asphalt be wary of the supply truck bumping the paver

16. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Dips, Humps & Bumps Long wavelength defect Built into underlying layers Minimal improvement in ride quality if thin surfacing applied Shape correction must be used to cater for longer wavelength

17. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Dips, Humps and Bumps

18. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Keeping the Road Surface Clean Surface contaminants can have a significant effect on ride Measuring device unable to differentiate dirt from pavement Sweep surface & remove loose gravel, dirt and clay One of the easier things to do

19. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Site Location & Delineation Clearly identify start and end points using physical markers Meet the testing authority on site Utilise guides eg bollards to assist in tracking if unsealed or no line marking

20. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Lead-in Must be of sufficient length to reach operating speed & commence acquisition Sufficiently long to avoid sharp acceleration Minimum 20 metres, ideal 50 metres Free of any defects (flow on effect)

21. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Flow on Effect

22. www.arrb.com.au Advancing safety and efficiency in transport through knowledge If the surface is too rough��. Correction will be required otherwise penalties may apply Identify offending section of pavement by analysing data at a smaller interval (Avoid need for rework by testing prior to application of final surfacing)

23. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Suitability of Measuring Equipment If IRI is required use a laser profiler or Walking Profiler Use an accredited supplier (this is stipulated by several SRAs)

24. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Conclusions Roughness (IRI) is a good measure of ride quality Roughness is more than just potholes and corrugations Penalties can be avoided if contractors are aware of factors affecting ride quality (Provision of incentives)

25. www.arrb.com.au Advancing safety and efficiency in transport through knowledge Thank you Questions???