Aerodynamic Stability of Bridge Stay Cables — Dynamic Tests and Simulations
-
2022-08-01
Details:
-
Creators:
-
Corporate Creators:
-
Contributors:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Edition:Laboratory Report
-
Contracting Officer:
-
Corporate Publisher:
-
Abstract:This project was a part of a multiyear, multipartner experimental investigation of the effects of wind on inclined stay cables that was initiated by the Federal Highway Administration (FHWA) in 2000. Between 2015 and 2017, the investigation on the galloping of inclined stay cables has focused on characterizing the influence of the cross-sectional shapes of stay cables, which have been observed to deviate from a perfect round shape, on the aerodynamics of the stays. This report documents the second phase of a project for this purpose. The first phase of the project, which started in 2015, included field measurements of cross-sectional shapes of stay cables and the measurements of their static aerodynamic force coefficients in a wind tunnel. The second phase covers dynamic tests on stay-cable replicas and the numerical simulation of their response to wind actions. Experimental results showed that for an inclination of 60 degrees at 0-degree yaw angle, large wind-induced oscillations were observed for most of the models and angles of attack investigated that could not be predicted solely based on the variations of the static force coefficients with Reynolds number and angles of attack. For these cases, increasing structural damping had only a small influence on the amplitude of the vibrations. For other orientations, inspection of the variations of the static coefficients with Reynolds number provided a good indication of the onset of the instability. For a cable model with helical fillets, increasing the Scruton number mitigated the vibrations. Comparison between experimental results and results from proposed numerical model showed that the three-dimensional, nonlinear, quasi-static modeling method can predict vibration vulnerability in some cases. Differences were observed in a cable-wind angle of 60 degrees and in cables with spatially variable cross-sectional shapes. Findings from numerical study included the following. Turbulence might be able to suppress the vibrations predicted in smooth flow. Numerically predicting aerodynamic vulnerability sometimes required a high resolution in parametric variation that would be difficult to achieve experimentally. One or more driving mechanisms for cable vibration might not have been identified, evidenced by an unexpected lack of influence from damping in some cases.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
File Type:
Supporting Files
-
No Additional Files
More +