INVESTIGATION OF ICE FORCES ON JACKET PLATFORM STRUCTURES: IN-SITU MEASURED DATA ON JZ20-2-1 PLATFORM IN THE CHINA BOHAI SEA

Abstract eng:
Offshore structures in high latitudes may experience huge loads and extensive vibration caused by drift ice. Numerous theoretical and experimental studies have been conducted on this topic. Because of simplifications in the theories and difficulties in simulating the real scenarios in the laboratory, such studies may significantly deviate from the experiments. There is little chance to verify these results by in-situ data due to the lack of data. In this paper, the in-situ data measured on the JZ20-2-1 platform, which is located in Liaodong Bay of the China Bohai Sea, are used to examine the ice forces exerted on jacket platform structures. First, two commonly used methods for determining design ice forces, namely the Korzhavin-Afanasev and Schawz formulas, are analyzed and compared to the measured ice forces data on the leg of the platform. These two formulas may underestimate design ice force for ice thickness below 20 cm, while giving reasonable predictions for 20-30 cm ice thickness. The modified Schawz formula for the Bohai structures produces reasonable results for thin ice and largely overestimates forces for thick ice. The dynamic ice force modes and ice failure patterns are identified. Self-excited ice forces are found happen to this structure by investigating the characteristics of ice force in frequency domain. The frequency of occurrence of each ice force mode and ice failure pattern are roughly estimated. For this structure, the dominant ice force mode is forced mode, and the main failure pattern of ice is crushing.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket