Correlation of bridge stay cable models using short time record data

Considerable recent attention has been focussed on understanding the dynamic response of cable-stayed bridges and stay cable vibration, including rain-wind induced vibration. The Fred Hartman Bridge in Houston, Texas, among others, has experienced large-amplitude rain-wind induced vibrations leading to modeling efforts. To validate models of the stay cables developed from design drawings among other objectives, several field tests were conducted. The 192 cables of the Hartman Bridge include eight 24-cable sets of nominally identical cables, providing an opportunity to examine fundamental frequency variation among sets. This paper presents results of several field tests using three different excitation approaches. All produced short-time data records of 20-45 seconds that were analyzed to determine fundamental frequency and in some cases modal damping estimates. A data analysis approach to identify families of harmonics from rotating machinery and gear system applications is applied for efficient and automated frequency estimation. Comparison of testing approaches, field test results, and discussion of correlation results and issues are presented in this paper.