DYNAMIC RESPONSE OF FIXED MARINE STRUCTURES

The dynamic response of a gravity offshore platform under wave loading and of a vertical wall breakwater under wave loading and ship-impact loading were studied for various soil conditions. The soil was assumed to be an elastic half-space and the same structural models were considered to be on soils with different shear modulus with and without hysteretic damping. The maximum displacements of every degree of freedom over the wave height were studied as functions of the incident wave frequency. The platform was modeled as a 2-D discrete mass system with two degrees of freedom on every mass-translation and rotation. The wave forces were determined using linear wave theory and the Morison equation for the cylinders and the diffraction theory for the platform caisson. The breakwater, a stiff and heavy structure was modeled as a rigid body supported on soil springs. Linear wave theory was used again to determine the wave forces and plots of the non-dimensional maximum displacements over wave height and the actual displacement versus the incident wave frequency for different soil properties were drawn. The same model was used for the ship-impact case and the displacements as a function of time for various forcing functions were studied.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  United States  02139
  • Authors:
    • Pollalis, S N
  • Publication Date: 1978-11

Media Info

  • Pagination: 131 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00310830
  • Record Type: Publication
  • Report/Paper Numbers: Thesis
  • Files: TRIS
  • Created Date: May 7 1980 12:00AM