Sensors

The instrumentation consists of two main categories of on-line sensors. The two categories have been termed as "dynamic" and "static" sensors. All sensors are embedded in the pavement structure. The dynamic sensors are used to measure pavement response to aircraft traffic where data are collected at frequencies between 100 and 1,000 Hertz. The static sensors are utilized to measure pavement response to changes of environmental conditions such as variations of temperature and moisture. Data from these sensors are collected on an hourly basis. In addition to on-line sensors, several off-line sensors have been installed. Data from these sensors are collected during field surveys. More detailed information on the field surveys is presented under the Data Acquisition section.

The sensors used in the project are listed below.

1. Strains are collected with three types of strain gages. They are the Carlson Strain Gages and the Carlson Joint Strain Gages manufactured by the Carlson Company, and the H-Bar Strain Gages fabricated at the Waterways Experiment Station.


2. Vertical displacements in the pavement structure are measured with Linear Variable Displacement Transducers or LVDT GAGES


3. Aircraft position, speed and acceleration are obtained from two sets of sensors. These are the Position Strain Gages and the Infrared Sensors


4. Environmental data in the pavement structure are obained from Temperature Gages for temperature, TDR Gages for moisture content and Resistivity Gages for the determination of frost and thaw lines.


5. Manual measurements of pavement surface elevations are made using embedded Brass Pins and of the water table using Water Wells located on the side of the runway.

Contact the Project Lead: Dr. David Brill, Airport R&D