Foundation reliability of a jack-up platform

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:55781

Karunakaran, D; Leira, B J ^[1]; Svano, G ^[2]; Moan, T ^[3]

---

1. SINTEF Structures and Concrete, Trondheim (Norway)
2. SINTEF Geotechnical Engineering, Trondheim (Norway)
3. NTH, Trondheim (Norway). Inst. of Marine Structures

A method for reliability analysis of fixed marine structures is outlined. Nonlinearities in hydrodynamic loading and soil behavior are accounted for by application of a time domain Simulation approach. The procedure accounts for the relative importance of low sea states causing high dynamic amplification and extreme sea states with a quasistatic type of response. This is achieved by the long term approach where the response characteristics for a number of sea states are weighted by the relative frequency of occurrence for each sea state. Statistical uncertainty in time-invariant parameters is included, and Importance Sampling Techniques are employed to produce sample vectors of these parameters. For each input vector, a long term response analysis is performed. As an example of application, the foundation reliability of a jack-up platform is analyzed. The effect of using different center points for the importance sampling is investigated. An optimal sampling is determined, and a convergence study is performed using increasing sampling sizes. The accuracy in a response surface approach as an alternative to full time domain analyses is also studied. The procedure is found to be highly applicable. Finally, a simplified foundation design method is calibrated by comparing with failure probabilities from a consistent reliability analysis.

• OSTI ID: 55781
• Report Number(s): CONF-940230--; ISBN 0-7918-1265-0
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DESIGN
DYNAMIC LOADS
FOUNDATIONS
OFFSHORE PLATFORMS
SOIL-STRUCTURE INTERACTIONS