Falling Weight Deflectometer Usage. A Synthesis of Highway Practice

摘要

Falling weight deflectometers (FWDs) have been in use since the 1980s. These devices are used to measure pavement deflections in response to a stationary dynamic load, similar to a passing wheel load. The data obtained are used to evaluate the structural capacity of pavements for research, design, rehabilitation, and pavement management purposes. The number of FWDs in use and the importance of their role in pavement engineering practice are expected to rise as agencies move toward mechanistically based pavement design. The interpretation of FWD data is a key method for estimating the in situ moduli of pavement layer materials. This synthesis of highway practice for FWD use will provide information needed to support guidelines for advancing the state of the practice. Information for this synthesis was gathered in the following four phases: Literature search and review Survey of state highway agency (SHA) representatives Communication with calibration center operators Communication with FWD manufacturers The literature review was conducted from several sources. TRB maintains the Transportation Research Information Services (TRIS) database, which contains bibliographical information from transportation-related research in the United States. Further information was found through the International Transport Research Documentation (ITRD) database. Individual SHA websites were searched for FWD usage information. The proceedings of the FWD Users Group meetings provided supplementary information to the synthesis. Published research articles, such as a pooled-fund study related to FWD calibration, were used as resources. Established guidebooks for FWD usage, such as the Long-Term Pavement Performance Program Manual for Falling Weight Deflectometer Measurements and the Florida Department of Transportations (DOTs) Falling Weight Deflectometer Handbook provided sensor spacings, load levels, and other useful data. In addition, the standards published in the Annual Book of ASTM Standards, procedures published by AASHTO, and articles in the Transportation Research Record provided valuable procedural descriptions.