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Appendix A
DATA FROM HARRIS SITE SURVEYS
HARRIS Data and Explanation of Threshold Values and Categories
M62 Hard Shoulder between Marker Post 146/9 and Marker Post 146/2
M62 Lane 1 between Marker Post 146/9 and Marker Post 146/2
Explanatory Notes
Threshold Values And Category
| Threshold Value | Threshold Value | Threshold Value | |||||
|---|---|---|---|---|---|---|---|
| Category | 0 | 1 | 2 | 3 | |||
| 3m Variance (mm2) | 1.25 | 3.75 | 7.5 | ||||
| 10m Variance (mm2) | 4 | 16 | 36 | ||||
| 30m Variance (mm2) | 55 | 165 | 275 | ||||
| Rutting (mm) (Average) | 5 | 10 | 20 | ||||
| Texture Depth (SMTD) (NS or OS) (mm) | 1 | 0.5 | N/A | ||||
Reference: Design Manual for Roads and Bridges, HD29/94, Part 2, Volume 7, Section 3.
Where,
Category 0 = Sound with no visible distress
Category 1 = Low level of concern, distress is not serious and no action is required unless extending over long lengths or several parameters are at high levels at isolated positions
Category 2 = Warning level of concern. The distress is becoming serious and needs to be investigated
Category 3 = Intervention level of concern. Action required
Example A
100 m length with a 3 m variance less than 1.25 mm² is considered to be Category 0, between 3.75 mm² and 1.25 mm² it would be considered to be Category 1, and so on.
Note: No 100 metre sections at the material location can be defined as Category 2. No 100 metre sections in Lane 1 at the material location can be defined as Category 1. The only sections defined as Category 1 are located in the hard shoulder.
