Fatigue analysis and life prediction of bridges with structural health monitoring data — Part II: application

Abstract This paper is a continuation of the paper titled “FATIGUE ANALYSIS AND LIFE PREDICTION OF BRIDGES WITH STRUCTURAL HEALTH MONITORING DATA — PART I: METHODOLOGY AND STRATEGY” with the emphasis on application of the developed method to the fatigue damage assessment of the Tsing Ma Bridge. Based on the methodology and strategy of the fatigue analysis presented in Part I, fatigue damage analysis and service life prediction of the bridge–deck section of the Tsing Ma Bridge (TMB) are carried out by using the strain-time history data measured by the structural health monitoring system of the bridge. The stress spectrum of the representative block of cycles at the location of strain gauges in a typical longitudinal truss is obtained by rainflow counting of cycles of stress history and statistical analysis on daily samples of daily stress spectrum. The effect of low stress cycles on the fatigue and service life is considered by modifying the stress range when it is less than a limit value of stress range. Results of fatigue damage and service life are calculated respectively by the model developed in Part I and Miner's rule are compared. The influence of updating on the calculation of fatigue damage and predicted service life is numerically investigated. The result shows that the magnitude of the stress range of the bridge–deck section considered on TBM is in the region of greatest concern of bridge fatigue, and values of fatigue damage and predicted service life, as an estimation of the state of fatigue for the bridge, are found to be reasonable.