Bridge Technology Consulting is the Principal Investigator for this bridge cable mock-up experiment. The mock-up is about 18-ft long and contains hundreds of wires with tension force of 1.3 million pounds. This level of tension is comparable to that on real suspension bridge cable. The project aims at mimicking the degradation mechanisms that exist on real bridge cables with the use of an environmental chamber that will be built around the cable mock-up. It is of paramount importance to point out that the entire cable cross-section is subject to load. Therefore there is full interaction between the cable load and surrounding degrading environment induced in the environmental chamber. This will provide realistic and providing sound health monitoring for ongoing degradation in bridge cables utilizing sensor technologies. The cable mock-up is made of the same high strength 5-mm wire that will be used for the cables of the Self-Anchored San Francisco-Oakland Bay Suspension Bridge in California. The project is funded by the National Science Foundation. Bridge Technology Consulting acknowledges the financial and technical support of TECHSTAR Inc./SPCC. The project includes the following:

• Construction of a bridge cable mock-up
• Instrumentation of the cable mock-up with different sensors to measure humidity, temperature, corrosion rate, wire breaks and strain degradation
• Construction of environmental chamber around the cable
• Accelerated degradation of the cable mock-up within the environmental chamber
• Comparison of degradation data gathered by sensors and the actual physical damage on wires
• Study of the dehumidification of the mock-up and evaluate the impact of dehumidification on the moisture condition inside the cable

Project Sponsor
National Science Foundation

Project Location
New York City, New York, USA

Cable Mock-up Features

• Length of Cable: 18 feet
• Diameter of Cable: 6 inches
• Total Force in Cable: 1.3 Million Pounds

Bridge Technology Consulting is pioneering the application of health monitoring technology to remotely track degradation in bridge cables. Since 2005, Bridge Technology has been pursuing different sensor technologies to remotely report corrosion rate, strain degradation, temperature and humidity levels inside a bridge cable. Recently, Bridge Technology Consulting led the first known installation of a corrosion sensor in a cable of one of the major suspension bridges in the northeast U.S. The following summarizes the sensor system installation procedures:

• Corrosion sensors were embedded in the bridge cable within the window of inspection while the cable was wedged.
• Each corrosion sensor is connected to a flex tape whose other end is connected to a data acquisition box, which in turn is connected in the vicinity of sensor location.
• Care was exercised during the rewrapping and compaction of the cable at the location where sensors were embedded in the cable to avoid damaging the flex tape.
• A data communication wire was extended down to the deck level to allow easy access and download of data.
• Currently, Bridge Technology Consulting is downloading data from the data acquisition box and conducting analysis of the data.
• Sensor data is used in the BTC Method to update the cable strength.