00936208

Component

https://doi.org/10.3141/1816-12

http://scholar.google.com...riss&publication_year=2002

Fiber-optic traffic classification and weigh-in-motion sensors were developed, constructed, and deployed in Florida. As vehicles pass over the sensors, deformations occur, causing light in the fibers' glass core to be refracted into the fibers' surrounding media. A data-acquisition system records change in the sensors' light intensity and uses computerized algorithms to determine axle presence or weights. Various encapsulation materials were available for securing sensors. Field trials indicated that the stiffness of these materials would greatly affect the sensors' output signal. This laboratory study focused on determining suitable candidate encapsulants on the basis of their elastic modulus. The study was conducted on six candidate encapsulants. Fifty-four sensors 200 mm (8 in.) in length were tested at pneumatic pressures of 665 kPa (95 psi) to evaluate the encapsulants. Polymers with elastic moduli from 3500 to 70 000 kPa (500 to 10,000 psi) were evaluated to determine their effects on the sensors' response in rigid materials. To determine relationships between encapsulant modulus and stress attenuated to the sensor, sensors were placed in the grooved bottom of an aluminum testing block with 12.6-, 25.4-, and 38.0-mm (0.5-, 1.0-, and 1.5-in.) grooves and tested pneumatically in a pressure vessel. Pressure transmitted to the sensors at the various depths was evaluated, showing that as the elastic modulus increased from 3500 to 10 500 kPa (500 to 1,500 psi) there was a significant decrease in the percent stress transferred. Moduli in excess of 10 500 kPa (1,500 psi) yielded minimal increase in percent stress transferred.

This paper appears in Transportation Research Record No. 1816, Pavement Management, Monitoring, and Accelerated Testing 2002.

English

p. 104-110

2002

Transportation Research Record

0309077419

Figures (10) ; Photos (1) ; References (11) ; Tables (2)

Encapsulation; Fiber optics; Laboratory studies; Modulus of elasticity; Polymers; Pressure; Sensors; Stresses; Weigh in motion

Encapsulants

Florida

Geotechnology; Highways; Materials; I35: Miscellaneous Materials

TRIS, TRB, ATRI

Jan 28 2003 12:00AM

• ACCELERATED PAVEMENT TESTING OF DRAINED AND UNDRAINED PAVEMENTS UNDER WET BASE CONDITIONS
• CONDITION-BASED METHOD FOR PROGRAMMING ROAD INFRASTRUCTURE MAINTENANCE
• CUMULATIVE TRAFFIC PREDICTION METHOD FOR LONG-TERM PAVEMENT PERFORMANCE MODELS
• DEVELOPMENT OF ROUGHNESS THRESHOLDS FOR PREVENTIVE MAINTENANCE ACTION AIMED AT REDUCING DYNAMIC LOADS
• ESTIMATING INTERNATIONAL ROUGHNESS INDEX FROM PAVEMENT DISTRESSES TO CALCULATE VEHICLE OPERATING COSTS FOR THE SAN FRANCISCO BAY AREA
• FRAMEWORK AND STRATEGY FOR IMPLEMENTING AN INFORMATION TECHNOLOGY-BASED PAVEMENT MANAGEMENT SYSTEM
• IDENTIFICATION OF PAVEMENT FAILURE MECHANISMS AT FHWA ACCELERATED LOADING FACILITY ULTRATHIN WHITETOPPING PROJECT
• MARYLAND STATE HIGHWAY ADMINISTRATION'S PROJECT SELECTION PROCESS: INTEGRATING NETWORK AND PROJECT-LEVEL ANALYSIS
• MEASUREMENT OF VERTICAL COMPRESSIVE STRESS PULSE IN FLEXIBLE PAVEMENTS: REPRESENTATION FOR DYNAMIC LOADING TESTS
• MULTICRITERIA ANALYSIS METHOD FOR PAVEMENT MAINTENANCE MANAGEMENT
• MULTIYEAR PAVEMENT REPAIR SCHEDULING OPTIMIZATION BY PRECONSTRAINED GENETIC ALGORITHM
• RISK-BASED LIFE-CYCLE COST ANALYSIS FOR PROJECT-LEVEL PAVEMENT MANAGEMENT
• TRUCKING TRENDS AND CHANGES THAT AFFECT PAVEMENTS
• USE OF DISTRESS AND RIDE QUALITY DATA TO DETERMINE ROUGHNESS THRESHOLDS FOR SMOOTHING PAVEMENTS AS A PREVENTIVE MAINTENANCE ACTION
• WEIGH-IN-MOTION APPLICATIONS FOR INTELLIGENT TRANSPORTATION SYSTEMS--COMMERCIAL VEHICLE OPERATIONS: EVALUATION USING WESTA