Long-Term Pavement Performance Program Falling Weight Deflectometer Maintenance Manual
Primary Topic: Pavement Maintenance
Description: The Federal Highway Administration's (FHWA) Long-Term Pavement Performance (LTPP) program operates eight Dynatest Model 8000 FWDs to collect deflection data on in-service pavement test sections across North America. LTPP has collected pavement deflection data in daily operations for 15 years, and in that time, the FWDs have had very little downtime. Continuous preventive maintenance is necessary to keep the complex hydraulic-electrical mechanical FWDs operating under demanding conditions to collect high quality data and pass rigorous annual reference calibrations. The owner's manual from the manufacturer provides guidance on most repairs and troubleshooting; however, eventually FWDs require service beyond routine maintenance–in other words, the time comes for a complete overhaul.
In spring 2003, the LTPP Southern Region support contractor overhauled one of the FWDs operated for the LTPP program. During the overhaul, the contractor documented the process photographically and described the process of disassembling and reassembling the FWD components and subcomponents. This document provides FWD owners, operators, and technicians information as a supplement to the Dynatest 8000 owner's manual. Maintenance guidelines are based on continuous operation of FWDs.
FHWA Publication Number: FHWA-HRT-05-153
Publication Year: 2006