Network and Project Bearing Capacity Surveys and Analyses Using Modern Techniques
Keywords:
Bearing capacity, Non-destructive technique, Integrated analyses, Remaining lifetime, Road conditionAbstract
In recent years bearing capacity surveys in the Swedish Road Regions Mitt and Melardalen have been performed on network and project level using integrated analyses of modern road survey techniques. The survey methods include:
· Digital video capture
· Measurements of the structure with ground penetration radar
· Measurement of the bearing capacity using falling weight deflectometer
· Sampling and laboratory testing
· Visual inspection of the drainage
· Visual inspection of the road surface condition and damages
· Measurements of the road surface condition with laser profilometer.
The results of the measurements are assembled, linked together, processed and analysed using Road Doctor™ for Windows software. The results can be shown on the computer screen as a continuous longitudinal profile for each project. All data are linked to the right length position. For each project, rehabilitation measures can then be optimised for each location. Thereby the design work is facilitated and the resource use and the costs for maintenance and/or rehabilitation can be reduced.
This technology was used in a 5-year bearing capacity survey project in Road Region Mitt of the Swedish National Road Administration for the years 1998-2002. The total length of the road network surveyed was about 5 000 km. The condition of the road structure and the road surface are shown for each project in continuous longitudinal profiles and on GIS-maps as 500 m average values. Road surface roughness, measured as IRI, and rutting values have been used to calculate the remaining lifetime for each 500 m of the surveyed paved road projects. The remaining lifetimes, depending on roughness and rutting as well as the bearing capacity condition, are shown on the GIS-maps. For gravel roads the bearing capacity described in three different ways is illustrated in the same way. These maps can be used for planning and
selection of maintenance and/or rehabilitation candidates.
