This paper provides an overview of an ongoing FHWA-sponsored research study entitled `Bridge Stay Cable Condition Assessment.' Specific experimental and analytical tools and procedures are being developed to accurately measure stay cable forces in the field. Measurement techniques include the use of embedded accelerometers for long-term monitoring or non-contact laser vibrometers for short-term field measurements. Parameters influencing stay cable vibrations such as sag-extensibility, bending stiffness, and intermediate springs and/or dampers are considered in the analytical solutions and parametric studies. The Finite Difference method was used to solve a newly-derived equation of cable vibration which includes all the above parameters. Simplified relationships between various dimensionless factors and the cable natural frequency were developed. Laboratory and field tests were planned and performed to develop and verify the proposed methodologies.
