The BTC Method is a comprehensive, probabilistic proprietary state-of-the-art, patented methodology that employs random sampling, principles of fracture mechanics, and statistical analysis for strength evaluation of bridge cables. The BTC Method provides accurate assessment of the proportions of broken and cracked wires, and forecasts service life of the bridge cable using degradation kinetics; thus providing invaluable information regarding budgeting and future inspections

The BTC Method was recently applied for the evaluation of the remaining cable strength at the Bronx-Whitestone Bridge and the Mid-Hudson Bridge.

"I have examined your report briefly and it seems reasonable. I think your argument on random selection without regard to appearance is reasonable."
Professor John W. Fisher, Lehigh University, Member of the National Academy of Engineering, May 2011.

"You have actually changed the paradigm of cable strength analysis and testing, and you have identified not only the proper sampling procedure but also defined a correct model of behavior. It is well worth the effort, because it provides answers to the owners of such bridges. You have done a monumental job, and I again congratulate you on the quality and value of your work, as well on your perseverance and ingeniousness."
Professor Theodore V. Galambos, University of Minnesota, Member of the National Academy of Engineering, May 2011.

"I have finished reviewing the report and I think it is an exceptionally comprehensive analysis of the problems in the cables of the bridge and can provide the authorities with an excellent basis for scheduling future bridge examinations and other actions to extend its life. The report not only covers all of the factors that go into the evaluation of the bridge wires, which gives it credibility, but also provides the reader with the step by step understanding of procedure on which the analysis is based."
Professor Alan W. Pense, Lehigh University, Member of the National Academy of Engineering, May 2011.

"Based on this review, my opinion is that the BTC method is a rational and rigorous approach for the evaluation of complicated main bridge cable systems. The field sampling plan, the laboratory test plan, and the analytical methodology incorporating the obtained data are well-documented and clear."
Professor Habib Tabatabai, University of Wisconsin Milwaukee , May 2011.

The BTC method presents the first comprehensive fracture-based analysis of cracked wires. The method employs principles of fracture mechanics to assess crack growth. Towards that end, Bridge Technology Consulting introduced a proprietary procedures for the identification of the fracture toughness of bridge wire.

• The BTC method fracture-based analysis includes the following:
• Recognizes the change in the crack front shape from curved (semi-circular or semi-elliptic) early in the crack growth to a straight crack front at failure.
• Evaluates the strength of cracked wires, which contain deep cracks, based on the fracture toughness criterion.
• Provides logical explanation to wire breaks.
• Utilizes the degradation of the effective fracture toughness to assess the time-dependent strength of cracked wires.
• Conduct Fractographic Examination of all fracture surfaces of wires to estimate the proportion of cracked wires by identifying cracks under stereo microscope.
• Proportion of cracked wires is used as a probabilistic quantity input in the BTC method.
• Provides distribution of cracked wires in the cable cross-section based on the input probability of cracked wires.