Reinforced concrete structures in deep sea are subjected to large forces of waves, earthquake and so on. Offshore structures must keep proper safety under these forces. Ultimate strengths, deformations and so on of the important offshore structures can be evaluated by the structural analyses bases on non-linear behaviours of reinforcing bars and concrete. Non-linear analyses by finite element method are applied to reinforced concrete beams and the calculation results are compared with the experiment results.
　Calculation resutls obtained by finite element method considered material non-linear properties are comparatively in accord with experiment resutls. It becomes clear that the calculation model in this paper is effective to analyze the reinforced concrete members.