Overview
The developments carried out these last 30 years in the field of road survey and evaluation of the evenness of the roads and airports are important but the national standards relating to it are not adapted any more (Edition 1977). This research will thus make it possible to define the bases of the recasting of the standards SN 640 520a "Planéité, Contrôle de la géométrie" while referring to the European standards force, to the recent technical documents (project FILTER, AIPCR) and to the specific requirements of the network managers.
The objective of the project is to provide recasting and updating of Swiss longitudinal and transverse evenness standards.
Following activities will be provided during the project:
- Bibliographic research ITRD
- Analysis and summary of results
- Satisfaction survey of users of measuring instruments, prime contractors and manager (PMS)
- Analysis and evaluation of results
- Elaboration of the elements necessary for an update of flatness standards
Funding
Results
The developments carried out during last 30 years in the field of the measurement and the evaluation of the evenness of roads and airfields are very consequent. The standards actually valid in Switzerland are based on a methodology developed in 1977 and cannot cover professionally the current needs for quality control of the bituminous layers any longer. The goal of this research is to provide the necessary conceptual bases to the revision of the Swiss standards regarding surveying techniques and evaluation methods.
By the evaluation of the various measurement systems for longitudinal unevenness, the requirements of the European standard EN 13036-5 must be considered. Due to the prescribed wavelength coverage and the desired flexibility in the choice of evaluation methodology, only profile-meter devices with appropriate wavelength coverage can be considered.
The IRI is currently the mostly used index for unevenness evaluation worldwide. This global index does not permit any distinction between the different wavelengths. However its simple computation and its good characterization of the global travelling comfort make it easy for use.
As soon as it was technically possible to get a complete recording of the unevenness profile of the road in the necessary range of wavelengths (0.5 to 50 m in accordance with the EN 13036-5 standard), the evaluation of the “unevenness energy” in different waves bands proved its ability to be a powerful evaluation technique.
The studies carried out in France in the 80's have established the partitioning in three waves bands (SW: 0.8 3.2 m / MW: 3.2 13 m / LW: 13 45 m). The quality levels of the travelling comfort and of the driving safety are thereby expressed with a notation (NBO) going from 0 (very poor) to 10 (very good) for each one of these bands. This characterization of linked by a “notation by bands of waves” tends to spread in Europe. This kind of characterization for a certain number of wave bands gains ever more significance in Europe. This type of indicator, in addition to its clear relationship to the comfort and the road safety, also makes possible to aim the construction procedures for obtaining better evenness quality of the road layers. This kind of wave bands index, like the IRI, can be calculated on the basis of any unevenness profile recording in accordance with the EN 13036-5 standard.
The new method of the “weighted longitudinal profile” is currently in an intense phas