Identification of Aeroelastic Parameters of Flexible Bridges

By Partha P. Sarkar, Asst. Prof., Dept. of Civ. Engrg., Texas Tech University, Box 41023, Lubbock, TX 79409-1023 A.M. ASCE,

Nicholas P. Jones, Associate Prof., Dept. of Civ. Engrg., The Johns Hopkins Univ., Baltimore, MD 21218-2686 A.M. ASCE,

and Robert H. Scanlan, Prof., Dept. of Civ. Engrg., The Johns Hopkins Univ., Baltimore, MD 21218-2686 Honorary M. ASCE.

Abstract:

Simultaneous extraction of all the aeroelastic parameters of a flexible bridge deck from a single section-model test has been a desirable goal not fully attained in the past. In the work here reported an experimental set-up was designed for executing coupled vertical-torsional motion of a section model. In the present instance the section model was located in proximity to a fixed model representing a section of the adjacent deck of a twin-deck configuration. A robust system-identification method was developed and applied to the noise-corrupted displacement time histories of the section model. The experimental set-up, the method of extracting the aeroelastic parameters, and the implications of the results obtained are presented in this paper. The tests were performed under both smooth and turbulent flow conditions, and in both the presence and absence of the second deck. This technique proved to offer good performance which is evident from the consistent aeroelastic parameters obtained.