FATIGUE LIFE PREDICTION AND MAINTAINANCE MANAGEMENT OF STEEL STRUCTURES SUBJECTED TO CORROSION

ABSTRACT This paper proposes a new method to predict the failure of steel structures subjected to fatigue and corrosion. A model is developed to determine changes in S-N curve of beams (i.e., intact plates) and connections subjected to simultaneous corrosion and fatigue environment. The fatigue damages of beams and connections are then modelled as stochastic processes. The first-passage probability method is used to determine the time-dependent probability of fatigue failure of plates and connections, and then system reliability analysis is carried out for a steel structure as a working example. It has been found that ignoring corrosion effect on S-N curves for beams and connections can lead to underestimation of fatigue life of corroded steel structures. It has also been found that corroded connections can be more vulnerable to fatigue failure than beams. Apart from that, a risk cost optimisation programme is applied to the working example to find the maintenance strategies that ensure the safe operation of steel structures and intend to minimise the total risk. The methodology proposed in this paper can help structural engineers and asset managers on repair and maintenance of steel structures subjected to simultaneous corrosion and fatigue.