FATIGUE RELIABILITY ASSESSMENT OF MULTI-LOADING SUSPENSION BRIDGES BASED ON SHMS

The estimation of fatigue reliability of multi-loading suspension bridges represents a challenging task in the consideration of randomness in multiple types of loading. This study presents a framework for fatigue reliability analysis of multi-loading long-span suspension bridges equipped with structural health monitoring systems (SHMS), and the Tsing Ma suspension bridge in Hong Kong is taken as a case study. A limit state function is first defined for fatigue reliability analysis. Probabilistic models of railway, highway, and wind loading are established based on the measurement data acquired from the SHMS. The daily stochastic stress responses induced by the multiple types of loading are simulated at the fatigue-critical locations of the bridge deck by using the finite element method and the Monte Carlo simulation (MCS) together with the loading probabilistic models established. The probability distribution of the daily sum of m-power stress ranges is estimated based on the daily stochastic stress responses. Finally, the fatigue failure probabilities of the bridge at the fatigue-critical locations are calculated for different time periods. The results demonstrate that the health condition of the Tsing Ma Bridge at the end of its design life will be satisfactory under current traffic conditions without growth.