Coaxial Cable Sensors and Sensing Instrument for Crack Detection In Bridge Structures

摘要

The objectives of this study are to pre-test analyze a decommissioned RC bridge that is selected in consultation with New York State Department of Transportation (NYSDOT) and design and plan the field tests of the bridge for the performance qualification and validation of distributed crack sensors and a fast Electrical Time Domain Reflectometry (ETDR) instrument to their full potential. The scope of work includes: (a) Selection of a decommissioned bridge; (b) Pre-test analysis of the select bridge structure to evaluate its progressive damage and determine the locations for sensor deployment; (c) Design and planning of field tests of the select bridge; (d) Field instrumentation with coaxial cable and fiber optical sensors for performance comparison; and (e) Summary of the findings of this study. Once fully validated and demonstrated in field conditions, distributed crack sensors and sensing instruments are expected to play a significant role in routine inspections and bridge ratings and in the rapid assessment of structural conditions for post-event evaluations and responses, improving the safety and security of transportation infrastructure at the height of a crisis. These roles are due primarily to their unique ability of permanently recording the widest crack a RC member experienced during a recent event. Such an attribute ensures the availability of damage data even if a fast ETDR system experiences malfunction during the event, greatly improving the reliability of bridge inspections.