The falling weight deflectometer (FWD) is an important—but complex—pavement management tool. The FWD Users Group recently held its fifth annual meeting in Austin, Texas, to help highway agencies learn how to keep their FWDs operating correctly and how to put the data from the FWDs to use in pavement management systems.

Hosted by Doug Chalman of the Texas Department of Transportation (DOT), the meeting was "quite a success," says the group's chairperson, Patty Polish of Nevada DOT. The 99 people who attended came from highway agencies across the United States, as well as from Romania and the Netherlands. Issues discussed included quality control and quality assurance, tips for operators, and the use and analysis of FWDs in pavement management.

Polish says the users group was particularly concerned with ensuring FWD operators are properly trained. "At this year's meeting, there was a large focus on the operator, and rightly so. A mistake or error in judgment on the part of the FWD operator could result in faulty information, which in turn could cause the outcome of the analysis to be erroneous or misleading."

The FWD calibration center operators held their annual meeting in Austin the day before the users group meeting. These meetings give center operators, FWD vendors, and the Federal Highway Administration (FHWA) staff a chance to share ideas and resolve any FWD calibration problems. Topics discussed this year included the annual review of calibration center operations, calibration of FWD reference load cells, and review of the guidelines for calibration center users.

The FWD Users Group was founded in 1992 by Bob Briggs, who was then working at Texas DOT's pavement section. Briggs had a great deal of experience with FWDs—Texas DOT had nine at the time—and he wanted to create an avenue for State highway agencies to exchange ideas and solve problems.

The FWD Users Group will meet next on October 5-7, 1997, in Myrtle Beach, South Carolina. For more information, contact Patty Polish at Nevada DOT (telephone: 702-888-7173; fax: 702-888-7501).

For information on FWD calibration, contact Max Grogg at FHWA (telephone: 518-431-4224, ext. 223; fax: 518-431-4208;
email: max.grogg@fhwa.dot.gov).

John Ragsdale, operator of the Southern Region Calibration Center in College Station, Texas, demonstrates the relative calibration procedure. Here he stacks the seismic sensors, or geophones; the results will tell him if the sensors are producing consistent results.

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