Reliability and Safety of Suspension Bridge Cables Using Continuous Health Monitoring Data

Columbia University, New York NY

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) The research objective of this award is to develop a methodology for reliability and safety factor assessment of suspension bridge cables over time using real-time measurements from sensors installed inside the cables. Today, small-scale sensors that can measure environmental parameters like temperature, relative humidity, pH, etc. and that can be fit inside thousands of tightly compacted steel wires are becoming available and are being tested for application in suspension bridge cables. Using these measurements either from the initial construction or from the last in-depth inspection, the proposed methodology will provide an estimate of the current cable strength as it evolves with time, as a function of the environmental conditions. By looking at how the strength changes with time, it will be possible to estimate the rate of deterioration of the cable strength and to extrapolate it for future prediction of the strength variation. This evolution in time is expected to be a deteriorating one. The proposed methodology will be based on a Monte Carlo simulation based approach to account for all the uncertainties involved in the problem. This methodology will be integrated and validated with experimental tests on single bridge wires as well as on a full scale model of a suspension bridge cable. If successful, the results of the proposed research will represent a dramatic improvement over the current inspection methods that are unreliable (e.g. visual inspection) and expensive (e.g. unwrapping and wedging the entire cable). These results will be of major interest to every suspension bridge owning agency to assess the safety and to improve the maintenance of such structures. Undergraduate and graduate students as well as high-school students and teachers will be involved at different levels of the research.