Residual Service Life Prediction And Reliabaility Analysis Of Imperfect Frame Structural System

During the period of processing and manufacturing, there will inevitably be some initial imperfections in the members of the actual engineering structure, which will make it become imperfect structure. Initial geometric imperfection is one of the most important imperfections in the actual structure. However, the research on the system reliability of frames with imperfect geometric members, whether new structures or existing structures, is in elementary phase. This paper attempts to make primary research on some problems about imperfect structural system with initial deflection members. The main contents are as follows:1. With the checking point method of logistic normal distribution to analyze the reliability of the structure. For those common variables difficult to determine their distribution, the logistic normal distribution, which is more abundant than normal distribution, is used to describe those variables. And in this paper, the calculating formula of the checking point method of logistic normal distribution is presented.2. Deriving the stiffness matrix of beam elements with initial deflection. The influence of flexural torque, axial force and shear deformation is considered to derive the j point softness matrix of arc curves, and then to set up the stiffness matrix of beam members with initial deflection. Through analysis made on comparison with the stiffness matrix of bar members, it proves the correctness of calculating result.3. Reliability analysis of the structural system with initial deflection members. Considering about the self-gravity influence on the initial deflection beam elements, set up its function and calculate the reliability and its mid-span deflection of the member. Combining the structure of some engineering, considering about the initial imperfection, this paper has analyzed the reliability of the imperfect frame structure about strength,stiffness and both of them.4. Residual service life prediction of existing steel frame structural system. According to the realities of existing engineering structures, the method of reliability analysis considering about resistance deterioration is presented, and based on reliability of structural system during the period and economic optimization, a optimization model for predicting the best residual service life of the existing steel frame structural system is set up, which can offer a proper reference for decision-making.