LQI-Based Optimization for Member Reliability of Offshore Jacket Platform Structures
|School||Harbin Institute of Technology|
|Keywords||Offshore platform Economic level Structural target reliability Life Quality Index(LQI) Optimum decision|
With the development of science and technology, the lack of resources emerged as a major issue, so the oil resource, which is the essential resource of the development of national industry and improvement of the people’s living standards, have played a important role. The offshore platform is the infrastructure producing oil, so the safe level of platform affects not only human’s life but also the development of the country. The safe level of platform must depend on the level of national economy. Employing the theory of Life Quality Index Standard (LQI standard), which is based on the theory of risk analysis and decision-making, and the principle of Investment-Benefits, a new method for safety level of steel jacket platform structures is proposed. The main works are as follows:1. Integrating Life Quality Index and Investment-Benefits, the optimization method for structural reliability is proposed on the basis of Life Quality Index; Applying the sequence approximate programming method, the complex optimum method is simplified.2. The optimization method is applied to steel jacket platform structures and the optimization reliability for members with axial tense force and bending force is separately calculated. The rule affecting economy level on target reliability is summarized by the calculating results. It is indicated that the method in this paper is more rational by comparing the result with the value of the calibrating method3. By calculating the differential coefficient between the design variables in the built engineering structure, the calculation of differential equation of the optimization model is simplified. To prove the rationality of the simplification, the rule affecting the differential coefficient on the reliability index is analyzed.The more rational method is proposed to determine the target reliability of engineering structure.