关键词: 台风, 甲板上浪, 导管架平台, 极限承载能力, 静力推覆分析, 失效模式, 倒塌机制

Abstract: For typhoon-induced wave-in-deck (WID) loads on fixed offshore structures, a calculation method and the procedure are established using the API hydrodynamic model and Stokes 5th wave theory. A generalized concept of reserve strength coefficient is proposed for assessing the bearing capacity of jacket platforms with environmental changes. Using a deep-water jacket platform as an example, the ultimate bearing capacity (UBC) curves and plastic strain distribution (PSD) of the design loads applied in three directions (end-on, broadside, and diagonal) are determined by considering two boundary constraints, i.e., clamped support and pile-soil nonlinear springs; further, the inherent relationship between the UBC and failure mode (FM) of the platform is investigated. Additionally, the WID loads at different heights are taken into account for pushover analysis of the UBC and FM of the platform. Results show that the WID load reduces the UBC of the platform; when the height of WID reaches a certain level, the PSD is concentrated to the top of the jacket while the main FM changes to topside rollover collapse. The results are consistent with our observations in the real platform after typhoon. This study valuable reference data is provided for assessing the anti-typhoon performance of deepwater jacket platforms.

Key words: typhoon, wave-in-deck, jacket platform, ultimate bearing capacity, pushover, failure modes, collapse mechanism