Reliability of Suction Caissons for Deep Water Floating Facilities

Author(s):  
Edward C. Clukey ◽  
Robert B. Gilbert ◽  
Knut H. Andersen ◽  
Rune Dahlberg
Keyword(s):  
Author(s):  
Lingzhi Xiong ◽  
Jianmin Yang ◽  
Xinliang Tian

Taut mooring systems have become a prospective solution for the station keeping of offshore floating facilities in deep water. In such scenario, the associated anchor foundations may withstand substantial uplift loads. To maximize the holding capacity, it is common to attach the anchor chain to the suction caisson at 60 to 70 % of the embedded depth. However, new phenomenon has been observed, which may be a challenge to the integrity of mooring systems, such as the trenching of the seabed near the suction caissons of floating systems. It is unclear whether trenching will induce significant effect on the integrity of mooring systems. To evaluate the influence of the seabed trenching, where existing commercial codes have not covered, a numerical model has been developed in this study. Based on this developed model, numerical simulations have been conducted with and without considering the trenching effect at the seabed. It is found that the seabed trench has a limited influence on the tension at fairlead but has a significant influence on both the tension and the inclination angle at padeye.


1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.


2016 ◽  
Author(s):  
Bert-Rik de Zwart ◽  
Jose Varghese ◽  
Prasanta Nayak ◽  
Aloke Saha ◽  
Anna Numpang ◽  
...  

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