Wind-vehicle-bridge interaction: Fatigue assessment and reliability

Many long-span suspension bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these long-span steel suspension bridges, fatigue assessment and reliability shall be performed from time to time during their service life. In this regard, structural health monitoring systems (SHMS) have been installed in a few long-span suspension bridges, but it is not clear how to make use of SHMS for fatigue assessment and reliability analysis. This study focuses on fatigue assessment and reliability analysis of long-span suspension bridges under multiple types of dynamic loads by integrating computer simulation with the measurement data from SHMS and by taking the Tsing Ma suspension bridge in Hong Kong as an example. This study leads to a powerful framework and an engineering approach for determining dynamic stress responses of long-span suspension bridges under combined highway, railway and wind loadings. This study also narrows down the gap currently existing between structural health monitoring technologies and structural condition assessment practices by developing a few approaches capable of performing fatigue assessment and reliability analysis with taking into account uncertainty and randomness inherent in both physical field and computer simulation.