Investigation of the Alexander L. Kielland failure - metallurgical and fracture analysis

Conference · Fri Jan 01 00:00:00 EST 1982 · Soc. Pet. Eng. AIME, Pap.; (United States)

OSTI ID:6171246

Almar-Naess, A; Moan, T; Haagensen, P J; Lian, B

On March 27, 1980, one of the 5 legs of the platform Alexander L. Kielland separated from the rest of the structure in a storm on the Ekofisk field in the North Sea. The failure started with the fatigue fracture of one of the lower tubular bracings attached to a vertical column. Laboratory tests, structural analyses and examination of fracture surfaces has established the following as the primary causes of the accident: (1) poor material properties of the hydrophone tube and poor welding resulted in partial cracking of the double fillet weld joining the tube to bracing D6; (2) the fracturing continued in the early history of the platform causing a redistribution of stresses; (3) 2 fatigue cracks propagated in a pure fatigue mode for ca. 60 to 100 mm from each initiation point at the hydrophone; (4) the fractures in the 5 other bracings joining the leg to the platform were caused by overloading; and (5) a fatigue analysis indicated that the design fatigue life of the fillet weld at the hydrophone mount was inadequate.

• OSTI ID: 6171246
• Report Number(s): CONF-8205277-
• Journal Information: Soc. Pet. Eng. AIME, Pap.; (United States), Vol. 2:OCT-4236; Conference: 14. annual SPE of AIME conference on offshore technology, Houston, TX, USA, 3 May 1982
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
NORTH SEA
OFFSHORE PLATFORMS
FAILURE MODE ANALYSIS
CRACK PROPAGATION
FAILURES
FATIGUE
FRACTURES
OIL FIELDS
STRESSES
WELDED JOINTS
ATLANTIC OCEAN
GEOLOGIC DEPOSITS
JOINTS
MECHANICAL PROPERTIES
MINERAL RESOURCES
PETROLEUM DEPOSITS
RESOURCES
SEAS
SURFACE WATERS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
020300* - Petroleum- Drilling & Production