In the present study, the reliability evaluation application during design, maintenance and repair phases have
been investigated for the girder of a ship’s hull. The objective of the project was to develop reliability-based
methods which are to be used for the design of ship structures, in particular by the calibration of the safety factors
in the design rules. In order to evaluate the structural strength, the extended model of the ultimate limit state
of the hull-girder, regarding corrosion and fatigue defects, has been used based using a time-dependent probabilistic
analysis. Time-dependent reliability has been evaluated using the required minimum elastic section
modulus; in the case of fatigue in a ship’s deck this process has been done using mechanical fracture and the
S-N curve. The results from the reliability evaluation using the Monte-Carlo simulation method and First-order
reliability methods (FORM), indicated that these two methods agreed well. Analysis of the corrosion defect
reliability showed a decrease of the structure’s reliability during its lifetime; hence it is possible to use the
reliability criteria in the design phase in order to achieve a better perception of the structure’s operation during
its lifetime with regard to environmental conditions. A comparison between the fatigue analysis results showed
that the fracture mechanics method gave more conservative results compared to the S-N curve method, because
of the way it considers early crack size.