Fatigue reliability evaluation of railway steel truss bridge based on measured load
Railway Engineering Research Institute, China Academy of Railway Sciences
In order to evaluate the fatigue of steel truss bridge, the reliability theory is introduced, and a fatigue reliability assessment method based on measured load data is proposed. According to the measured load data of a railway steel truss bridge, the random vehicle load model is established. On the basis of considering the randomness of vehicle loads, the fatigue stress spectrum of members of steel truss bridge is analyzed by combining Monte-Carlo method with finite element method, the variation of fatigue reliability with time is calculated, and the influence of variability of vehicle loads and load effects on the fatigue reliability of members is discussed. Finally, the fatigue reliability of steel truss bridge system is studied by β-bound method and static analysis method. The results show that the fatigue stress spectrum of the members based on random vehicle load shows a single peak distribution. The increase of vehicle load and variability of load effect have great influence on fatigue reliability of components, when the growth rate of vehicle load and the variation coefficient of equivalent stress increase to 5%, the fatigue life of the component is greatly reduced. The β-boundary method combined with the static analysis method can quickly determine the failure mode of the steel truss bridge, and the fatigue life of the system is less than the fatigue life of the members. In general, the steel truss bridge fatigue reliability assessment method based on measured load can effectively use the monitoring data and has good applicability.