Wind-Induced Accidents on the Transition Section of a Cable-Stayed Bridge: Cause and Remedy

This case study investigates two of the wind-induced vehicle accidents that occurred on a cable-stayed bridge in Korea over the past 20 years. Both of these incidents happened at the approach deck of the bridge, where the elevation from the sea level was only about 57% of the main span height. The investigation was focused on determining whether specific structural components or geometrical characteristics around the accident locations were responsible for these incidents. To achieve this, scaled-down vehicle and bridge deck models were used in a series of wind-tunnel tests. The results show that the wind load on the vehicles increased by 3–4 times near the accident locations. The primary cause of this anomaly was attributed to the rapid change in deck width. Furthermore, a risk assessment, which considered traffic and wind environments, showed that the risk level at the accident location was 100 times higher than at any other location on the bridge due to these unique characteristics. Additionally, further risk assessment revealed that two measures, traffic control and wind barrier installation, could mitigate the risk at the accident location.