Abstract
Recently, many papers are reported about safety of steel structures suffered from large earthquakes. Especially in Petroleum storage tank, extensive efforts are required to establish an estimation technique of the fracture behavior and the criterion of maintenance under cyclic plastic strains so as to prevent or minimize fatal accidents.
Although it is thought, the shell-annular joint of Petroleum storage tank, there are affected several percentage of plastic strains by large moment under the earthquake, characteristics of fatigue in such as ultra low cycle, especially, about crack propagation life studies are rarely done.
This paper makes an application of an approximate method to evaluate crack growth rates under cyclic large plastic bending tests. Proposed formula shows good prediction of crack growth rates both in alternative and repeated bendings.
