Analytical method of combining global longitudinal loads for ocean-going ships

Based on three kinds of still-water load models, i.e. the Ferry Borges–Castanheta, Poisson and alternating renewal models, three methods of determining characteristic values of still-water loads for ocean-going ships have been established and evaluated. These models of still-water loads have been applied to establish models for combining still-water and wave loads, by which consistent combined characteristic values are predicted numerically. Based on the point-crossing method, an analytical formula for the combined characteristic value of still-water and wave loads for ocean-going ships is derived by adopting Poisson load models, the exponential peak distribution of wave loads and the minimum of Turkstra’s combination solutions. The numerical analyses show that the analytical formula developed has the same accuracy as the numerical methods.