Experimental study on the aerodynamic force and vibration of a scratched stay cable perpendicular to the wind

The wind load and wind-induced vibration of stay cables, as the primary load-bearing component in cable-stayed bridges, are highly important. Inevitably, cables experience scratches during production, transportation, and installation. Scratches may have an important effect on a cable's aerodynamic force and wind-induced vibration. Consequently, three sectional cable models with varying scratches were prepared for wind tunnel tests. The incoming wind was perpendicular to the cable model. The aerodynamic and vibration responses in precritical, critical Reynolds number regions were investigated. The results showed that scratched cables exhibit Reynolds number effects similar to those of smooth cables. Within attack angles ranging from 50° to 85°, scratching significantly reduced the corresponding Reynolds numbers of the TrBL0-1 and TrBL1-2 transitions. This caused the scratched cable to vibrate substantially at a lower Reynolds number (wind speed) than the smooth cable. There is a smaller attack angle range between 50° and 90° in which scratches cause the average lift coefficient to climb slowly with the Reynolds number, without a bistable phenomenon. This implies that there is no significant vibration. The critical Reynolds number effect effectively predicts the vibration of the scratched cable, and the complex flow in the critical Reynolds number region limits the accuracy of the Den Hartog criterion.