The Indian River Inlet cable stayed bridge: the effect of wind speed and direction on estimates of stay cable forces
Date
2017
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
The objective of this study is to estimate the tension in the stay cables of the
Indian River Inlet bridge using measured cables vibrations in conjunction with
dynamic cable theory. In addition, to evaluate the effect of the wind speed and
direction on the ability to estimate the stay cable forces. A MATLAB script is
developed to automate the data processing, using spectral density techniques to
identify the cable natural frequencies and from these, estimate the tension. Making use
of taut cable theory, which combines frequencies and tension force in a relationship,
one can be extracted by relying on the other. The acceleration data that is considered
for analysis purpose in this study is from two wind events: Winter Storm Jonas
January, 23rd 2016, and Hurricane Matthew October, 9th 2016. The results show that
the taut string theory is an accurate and straightforward method to estimate cable force
by knowing the natural frequency of the cable. From the analysis work, it is seen that
all the estimated tensions were approximately within the ultimate maximum and
minimum ranges from the construction requirements with different percentages of no
more than 15%. For average or gust wind speeds between 25 mph and 55 mph, the
tension in the stay cables can be estimated without requirement for certain
characteristics using taut cable theory. In addition, the directions from north or north
east for the wind data provide acceptable data for estimating the tension in the stay
cables. moreover, there is not enough information to determine the validity of other
directions to estimate tension for cables.
Description
Keywords
Applied sciences, Acceleration data, Cable natural frequencies, Dynamic cable theory, Stay cables, Tension, Wind speed