OFFSHORE PLATFORMS: OBSERVED BEHAVIOR AND COMPARISONS WITH THEORY

The measured static and dynamic response characteristics of four jacket-type platforms in water depths up to 373 feet are described. Fundamental periods and damping were determined both by free vibration tests and spectral analysis of random response data. For each platform, measured end-on and broadside natural periods were nearly equal with values ranging from 1.5 to 1.9 seconds; the theoretically predicted natural period for one of these platforms was close to the measured value. Damping estimates range from approximately 1.0 to 5.0 percent of critical depending on the methods of testing and data analysis. For one platform spectra of both deck motions and wave heights are presented; measured amplitudes of response are compared to theoretical predictions. Motions predicted using regular Airy wave theory overestimate the measured motions for the tested platforms and the low sea states considered.

• Supplemental Notes:
  • Presented at the Eighth Annual Offshore Technology Conference, Houston, Texas, May 3-6, 1976.
• Corporate Authors:

  Offshore Technology Conference

  6200 North Central Expressway
  Dallas, TX  United States  45206
• Authors:
  • Ruhl, J A
• Conference:
  • Presented at the Eighth Annual Offshore Technology Conference, Houston, Texas, May 3-6, 1976.
• Publication Date: 1976-5

Media Info

• Features: References;
• Pagination: p. 333-352

Subject/Index Terms

• TRT Terms: Damping (Physics); Offshore platforms; Ship motion; Structural analysis; Vibration
• Old TRIS Terms: Structural vibration
• Subject Areas: Bridges and other structures; Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00138216
• Record Type: Publication
• Source Agency: Offshore Technology Conference
• Report/Paper Numbers: V2, OTC 2553 Proceeding
• Files: TRIS
• Created Date: Aug 23 1976 12:00AM