Study on stability improvement of suspension bridge with high-sided vehicles under wind using tuned-liquid-damper

Smooth and safe traffic on the highway system is crucial for a modern society. As the backbone of a highway system, key long-span suspension bridges as well as moving high-sided vehicles on the bridges are vulnerable to strong wind. Excessive vibration of bridges and vehicles may cause the bridge aerodynamic instability and vehicle accidents. When wind is strong, the excessive torsional response of the bridge also contributes to the discomfort of drivers or the occurrence of overturning accidents of vehicles moving on it. Potentials of adopting the tuned-liquid-damper (TLD) system as an enhancement measure for the stability of suspension bridges with high-sided vehicles are evaluated. Firstly, a general shallow water sloshing model in rectangular containers under off-axle rotation, lateral and vertical excitations is developed. The analytical platform of the general 3-D bridge-vehicle-TLD system under wind and road roughness excitations is introduced. Secondly, a parametric study of the off-axle TLDs in controlling torsional motion of a simple single torsional mode bridge model under broadband white noise excitation is conducted to investigate the effectiveness and mechanism of the TLD on torsional motion. Finally, a numerical analysis of TLDs installed on a real suspension bridge-vehicle-wind system in time history is carried out considering interactions between the multimode bridge structure, multiple vehicles and the wind excitation. The results suggest that the off-axle TLD system can effectively suppress the torsional response of the suspension bridge through acting as a pendulum damper in addition to a typical sloshing damper, but has little direct suppression effect on the vibrations of vehicles.