The Calculation And Reliability Analysis Considering Corrosion On The Ultimate Strength Of Box Girders

Recently, the method which bases on structure ultimate strength developed very rapidly in the domain of structure engineering. It has been a trend that the design method which bases on structure ultimate strength replaces the traditional method which bases on the theory of elasticity. The study indicates we must take into account several possible destructive modes such as buckle and yield et al and consider the non-linear effect of post-buckling and post- collapse of components.Then, a step-by-step increase of vertical bending curvature is applied to the hull girder assuming that the plane cross section remains plane. At each incremental step, the stress of the cross section is evaluated using the average stress-strain curves of the elements as well as the incremental bending moment due to the curvature increment.This method was first used by Smith. Firstly, it needs to separate the girder hull into many elements-compressive one and tension one. Secondly, when the ship is in hogging or sagging, you should assume one curvature value so you can get the moment value of every element. And then you may add up all the moment of every element. Thirdly, you mast judge whether the moment is the ultimate moment. If not, increase the curvature, and redo the above steps until get the ultimate strength.In the thesis the author analyzes the tripping of stiffened panels by three different methods. Based on the above method, the author calculates the ultimate longitudinal strength of a boxlike girder, several ships and many stiffed panels by program. And then checks with some famous experts' results. The result is approving. Also the author analyses the reliability of ship considering corrosion. At last an experiment is done to verify the theory.