The statistical characteristics and parameters of loads and resistances are systematically studied for the development of probabilistic limit state design method for steel jacket offshore platforms in the China offsho...The statistical characteristics and parameters of loads and resistances are systematically studied for the development of probabilistic limit state design method for steel jacket offshore platforms in the China offshore area. The mean value, standard variance and distribution pattern of resistances and loads in different base perieds are presented. The statistical parameters of structural member resistance, self-weight, deck live load, and environmental loads such as wind, wave, current and ice, which are drawn on a large amount of observatian data of offshore environmental factors, and the design data of platforms in China Bohai Sea form the data set, providing a necessary basis for the calibration of load and resistance factors to realize the reliability-based design of jacket platform structures.展开更多
Adopting the load and resistance factor design format, the design method for steel jaeket platform structures is developed. Firstly, the limit state equations and design format for steel jacket platform structures are...Adopting the load and resistance factor design format, the design method for steel jaeket platform structures is developed. Firstly, the limit state equations and design format for steel jacket platform structures are introduced. Then, the ratio of live load effect to dead load effect is estimated. The target reliabilities for design of offshore structures in China offshore area are calibrated by past practice in API RP2A-WSD code. The load and resistance factors are optimized by minimizing the difference within the target reliability and the resulting reliability over the range of load effect ratios. Considering the concurrence of different loads, load combination factors are obtained through an optimization process, and the relation between the load combination factor and load correlation coefficient is established. Finally, the design formulae for steel jacket structures in China offshore area are recommended.展开更多
In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of inc...In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of incremental dynamic analysis results for both directions of the platform shows that the lateral strength of the platform in the float over direction is less than its lateral strength in other direction. Dynamic characteristics measurement of a scale model of platform was also performed using forced vibration tests. From experimental measurement of the scaled model, it was observed that dynamic characteristic of the platform is different in the float over direction compared to the other direction. Therefore, a new offshore installed bracing system for the float over direction was proposed for improvement of seismic performance of this type of platform. Finally, the structure with the modified system was assessed using the probabilistic seismic assessment method as well as experimental measurement of its dynamic characteristics. It was observed that the proposed offshore installed bracing system improves the performance of platforms subjected to strong ground motion.展开更多
基金This researchis partiallyfunded bythe National Natural Science Foundation of China (Grant No.59895410)
文摘The statistical characteristics and parameters of loads and resistances are systematically studied for the development of probabilistic limit state design method for steel jacket offshore platforms in the China offshore area. The mean value, standard variance and distribution pattern of resistances and loads in different base perieds are presented. The statistical parameters of structural member resistance, self-weight, deck live load, and environmental loads such as wind, wave, current and ice, which are drawn on a large amount of observatian data of offshore environmental factors, and the design data of platforms in China Bohai Sea form the data set, providing a necessary basis for the calibration of load and resistance factors to realize the reliability-based design of jacket platform structures.
文摘Adopting the load and resistance factor design format, the design method for steel jaeket platform structures is developed. Firstly, the limit state equations and design format for steel jacket platform structures are introduced. Then, the ratio of live load effect to dead load effect is estimated. The target reliabilities for design of offshore structures in China offshore area are calibrated by past practice in API RP2A-WSD code. The load and resistance factors are optimized by minimizing the difference within the target reliability and the resulting reliability over the range of load effect ratios. Considering the concurrence of different loads, load combination factors are obtained through an optimization process, and the relation between the load combination factor and load correlation coefficient is established. Finally, the design formulae for steel jacket structures in China offshore area are recommended.
基金sponsored by POGC (Pars Oil and Gas Company,No.132 "Investigation of Structural Health Monitoring of Steel Jacket Offshore Platforms")The financial support of POGC is gratefully acknowledged
文摘In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of incremental dynamic analysis results for both directions of the platform shows that the lateral strength of the platform in the float over direction is less than its lateral strength in other direction. Dynamic characteristics measurement of a scale model of platform was also performed using forced vibration tests. From experimental measurement of the scaled model, it was observed that dynamic characteristic of the platform is different in the float over direction compared to the other direction. Therefore, a new offshore installed bracing system for the float over direction was proposed for improvement of seismic performance of this type of platform. Finally, the structure with the modified system was assessed using the probabilistic seismic assessment method as well as experimental measurement of its dynamic characteristics. It was observed that the proposed offshore installed bracing system improves the performance of platforms subjected to strong ground motion.
