Falling Weight Deflectometer Calibration Center and Operational Improvements Falling Weight Deflectometer Calibration Center and Operational Improvements: Redevelopment of the Calibration Protocol and Equipment

2011PDFTech ReportFHWA-HRT-07-040CLRP Report No. 2010-03DTFH61-04-C-00041Flexible pavementsPavement designPavement performancePreventive maintenanceRehabilitation (Maintenance)Rigid pavementsBackcalculationCalibrationResearch HubDeflection measurement, Falling weight deflectometerFWDPDDXlong-term pavement performance programMechanistic-Empirical Pavement Design GuideSpecific Pavement Studies (LTPP)DesignHighwaysPavementsDesign of Pavements, Railways and GuidewaysUnited StatesUnited States. Federal Highway Administration.United States. Federal Highway Administration. Office of Infrastructure Research and DevelopmentIrwin, Lynne H.Orr, David P.Atkins, DanielCornell UniversityCornell Local Roads ProgramUnited States. Federal Highway Administration. Office of Infrastructure Research and DevelopmentUS Transportation CollectionThe objective of this project is to upgrade the existing falling weight deflectometer (FWD) calibration system to make calibration sustainable for the next decade without a loss of quality while ensuring that any new procedures are compatible with all brands of FWDs sold in the United States. This involves upgrading the hardware and software used in calibration to take advantage of improvements in technology. The primary result of the FWD calibration procedure is to obtain gain factors used to correct FWD load and deflection sensor data to agree with the calibration instrumentation. Changes incorporated in the new FWD calibration procedure include replacing the reference linear variable differential transducer with an accelerometer for deflection sensor calibration, developing a stiff multiple-sensor stand to allow calibration of all deflection sensors simultaneously, updating the calibration software to a modern programming language with the ability to electronically read data from each brand of FWD, and using modern data acquisition techniques to eliminate sensitivity problems from the older Strategic Highway Research Program FWD calibration protocol. The time to complete an FWD calibration was greatly reduced. This report outlines the updated procedures and provides details about the equipment and methods needed to perform the updated protocol