The Pushover Analysis Of Jacket Platform

Because of its simple structure, strong adaptability, safety and reliability and low cost, jacket platform widely used in the offshore oil exploiting, especially in the shallow sea water oil exploiting jacket platform is dominant. As a large statically indeterminate steel structure jacket platform designing according to the relevant regulations, generally has redundancy strength. However, the global climate is becoming warmer and warmer, extreme environment occurring more and more frequently. Some of the wind speeds have exceeded the design wind speed according to the rules. So the jacket platforms must have the sufficient reserve strength, also called ultimate bearing capacity to avoid the disasters under the extreme environment. In order to evaluate the safety and reliability of the platform under the super typhoon, must evaluate the ultimate strength of the platform, pushover analysis is to get the ultimate strength platform, so do a pushover analysis for the platform having important practical engineering significance.Modeled the jacket structure with SACS program according to the structural design drawings, then applied the loads in the operating load case and extreme load case according to the relevant regulations, the boundary conditions of the8pile heads consider the interaction of pile and soil. Evaluate the strength of the platform by doing a static analysis importing the PSI data written based on the soil data. After static analysis, do a pushover analysis using the regression marine environment loads. Calculated ultimate bearing capacity of the platform, and then evaluate the safety and reliability of the platform under the super typhoon. The main contents of this paper are as follows:1. Be familiar with the structure of jacket platform; understand the API rules of platform design and the AISC regulations. Learn the basic theory and operation of SACS program;2. Model the jacket platform according to the relevant data, and then do a static analysis for the jacket platform; understand the definition of each load and the way of applying loads; study the definition of PSI in the API rules, understand mechanism and processing method of PSI in the SACS program;3. Study the knowledge of the ultimate strength, especially introduce the basis of the elastic-plastic and large deformation and incremental finite element method;4. Do a regression analysis of marine environment parameters based on the investigation report, then do a pushover analysis for the platform with the regression marine environment loads, study the basic theory and process of the pushover analysis in SACS program;5. Analyse and process the result of the pushover analysis and explain the result.Through the static analysis and collapse analysis, we can draw conclusions as follows:the static strength of the platform meets the requirements of the design standards; and the reserve strength is enough, the minimum of the reserve strength ratio is1.95occurring at0°angle, so the angle of0°is the most dangerous.