COST 336
Use of Falling Weight Deflectometers in Pavement Evaluation
Chairman: Mr. Egbert Beuving (NL)
Stichting Centrum voor Regelgeving en Onderzoek in de Grond-, Water- en Wegenbouw en de Verkeerstechniek - CROW
Fax: 31 318 62 11 12
E-mail: beuving@crow.nl
Vice-Chairmen:
Mr. Brian Ferne (UK)
Transport Research Laboratory
Fax: +44 1344 77 03 56
E-mail: ferneb@h.trl.co.uk
Mr. Ole Fog (DK)
Danish Road Institute
Fax: +45 46 30 01 05
E-mail: fog@vd.dk
Scientific Secretary:
European Commission
Directorate General for Energy and Transport
Fax: +32 2 296 37 65
Email: COST-Transport@ec.europa.eu
Duration
3 years; to June 1999
Participation
20 COST Countries: Austria, Belgium, Croatia, Denmark, France, Finland, Germany, Greece, Hungary, Iceland, Ireland, Italy, The Netherlands, Portugal, Romania, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
Objectives
COST 336 aims to draw up a European code of good practice for the use of falling weight deflectometers (FWDs) in pavement evaluation. This will involve developing an existing harmonisation proposal to incorporate strengthening evaluation on the basis of FWD tests, and establishing common requirements for calibration of measurements and machines. The potential for using FWDs in evaluation at network level will also be assessed, and the final objective of the project will be to establish a preparatory basis for European standardisation in the field.
Wider objectives are to avoid dependence on individual FWD types and to generate a more harmonised market for organisations involved in bearing capacity testing using FWDs.
Programme/Deliverables
COST 336 involves three main tasks, each of which has a significant number of subsidiary deliverables. The task areas are:
- Post-processing of FWD data.
- Applicability of FWDs at network level.
- FWD calibration.
The primary deliverables, which form the component parts of the common code of good practice for the use of FWDs, are:
- Specification for a FWD data post-processing model.
- Guidelines document for the FWD data post-processing.
- Guidelines document for the use of FWDs at network level.
- Calibration protocols for FWD machines.
- Requirements for FWD calibration stations.
- European seminar on use of FWDs at network level.
Background
COST 336 deals with issues surrounding the use of falling weight deflectometers for measuring the bearing capacity of road pavements. The FWD was developed in Europe, and is now in world wide use. Deflection testing is a growing requirement in modern pavement maintenance management, and it has already been implemented as a routine procedure in some European countries. The relatively sophisticated information made available by using this method will enable much improved decision making at national and local level in the high priority areas of road construction and maintenance.
Use of FWDs is one of a number of technical areas selected by national government road research laboratories for addressing at European level. Harmonisation in this area is seen as a key requirement for the development of a single market for road monitoring equipment and services.
Benefits to Different Users
- To government and the public:
- Common basis for evaluation of road standards and possible traffic load limitations due to different structural capacity.
- To the financing body:
- Investments are tailor made for the structural condition of each road section and the expected traffic load during the chosen design period. No loss of funds is incurred by paving overlays with long lifetime on road sections with a short residual structural lifetime.
- To the road maintenance engineer:
- Precise information can be provided on the structural condition of all layers in road sections. Thus, better informed decisions can be made for the repair of drainage related and other invisible defects, before the problems become much greater in terms of cost and safety implications.
- To the project management systems (PMS) engineer:
- The possibility to optimise cost/benefit effects at project level, by applying appropriate new overlays very close to the end of a road section's structural lifetime.
- To the researcher:
- A common data standard is provided for analysis and refinement of road deterioration models, with a far larger amount of data for analysis than is available in each individual country.
Related activities
Publications
Finite Element Dynamic Analysis of Falling Weight Deflection Measurements
Manuscript completed October 1997
1997 - 36 pp - 21.0 x 29.7 cm
Use of Falling Weight Deflectometers at Network Level - Information Gathering Report
Manuscript completed in February 1998
1998 – 65pp – 21.0 x 29.7 cm
Word file for download (314 KB)
Compressed Word file for download (271KB) | 
