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Experimental Modeling and Stay Force Estimation of Cable-Stayed Bridges

Kangas, Scott

Abstract Details

2009, PhD, University of Cincinnati, Engineering : Electrical Engineering.
Advances in material and construction technology has resulted in long span bridges being built with increasing regularity. Because of their aesthetic value and reduced construction requirements, among many other factors, cable-stayed bridges have become the design of choice for medium to long spans. As confidence grows in bridges of this type, their span lengths are being pushed to new boundaries. This has had the unavoidable consequence of creating a more lively structure. The collection of cables on a given stay bridge possess a wide range of closely spaced natural frequencies and any arbitrary source of excitation, i.e., wind, traffic, superstructure motion, is likely to provide energy at an arbitrary resonant cable(s) frequency.

Cable-stayed bridge designs have continuously evolved in response to experiences encountered with previous designs. A study put forth by the Federal Highway Administration (FHWA) provided a collective discussion for what types of modifications have been applied and the degree of their success and put forth a consistent set of guidelines for reducing cable vibrations in future bridge designs. As mentioned in the study, many early bridge designs did not incorporate measures to reduce cable vibrations, but those that did have reported few cable concerns.

Two cable-stayed bridges recently constructed by the Ohio Department of Transportation (ODOT) incorporate measures put forth by the FHWA study to mitigate stay motion. Also, following recent design trends, the stays at this bridge were constructed without the use of grout for the purpose of inspection and, if necessary, strand replacement. A common approach for objective condition assessment of the stays involves experimentally estimating cable force. The predominant method for estimating cable force uses an indirect approach where an accelerometer is mounted on the cable sheath, or a non-contact laser vibrometer is aimed at the sheath from a distance, to measure cable resonant frequencies and from these frequencies cable tension can be estimated. Several experiments were performed by the University of Cincinnati Infrastructure Institute (UCII) to determine the viability of using traditional vibration techniques, which assume an integral sheath, to estimate cable tension with this new configuration.

Arthur Helmicki, PhD (Committee Chair)
James Swanson, PhD (Committee Member)
Ali Minai, PhD (Committee Member)
Victor Hunt, PhD (Committee Member)
Randall Allemang, PhD (Committee Member)
181 p.

Recommended Citations

Citations

  • Kangas, S. (2009). Experimental Modeling and Stay Force Estimation of Cable-Stayed Bridges [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258474356

    APA Style (7th edition)

  • Kangas, Scott. Experimental Modeling and Stay Force Estimation of Cable-Stayed Bridges. 2009. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258474356.

    MLA Style (8th edition)

  • Kangas, Scott. "Experimental Modeling and Stay Force Estimation of Cable-Stayed Bridges." Doctoral dissertation, University of Cincinnati, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258474356

    Chicago Manual of Style (17th edition)