Analysis of impact loads on a self-elevating unit during jacking operation
Artikel i vetenskaplig tidskrift, 2017

A method is presented that enables the analysis of weather window assessments for the installation and retrieval phases of a self-elevating unit (SEU). The method takes site-specific parameters, defined as soil type and water depth, into account in addition to vessel-specific and environmental parameters. The inclusion of site-specific parameters is the novel contribution compared to assessment methodologies used today. A simulation model is presented that incorporates a coupled non-linear time-domain analysis of vessel motion and soil-structure interaction. Soil deformation behaviour during impact is described by resistance curves based on a bearing capacity theory. A structural evaluation criterion against which impact forces are compared is used for weather window assessments. The simulation model is applied on a case study utilizing different soil types to study impact forces and the capacity of the structure for withstanding such impacts and eventually performing a weather window assessment. The results show that the jacking operation can be divided into two phases when it comes to loads on the spudcan: a phase dominated by vertical forces followed by a phase dominated by horizontal forces. It is found that including soil deformation behaviour is of paramount importance to the magnitude of the resulting impact forces and that class-recommended practice does indeed produce rather large force estimates. Thus, assessments where site-specific parameters are incorporated could definitely increase the operable weather window for SEUs, and, consequently, increase the economic competitiveness of, for example, the offshore wind industry.

weather window

self-elevating unit

structural capacity

impact loads

bearing capacity

installation

installation

Författare

Jonas Ringsberg

Chalmers, Sjöfart och marin teknik, Marin teknik

Viktor Daun

SSPA Sweden AB

Fredrik Olsson

SSPA Sweden AB

Journal of Offshore Mechanics and Arctic Engineering

0892-7219 (ISSN)

Vol. 139 1-9 031602-1

Ämneskategorier

Maskinteknik

Tillförlitlighets- och kvalitetsteknik

Annan materialteknik

Farkostteknik

Marin teknik

Drivkrafter

Hållbar utveckling

Innovation och entreprenörskap

Styrkeområden

Transport

Energi

Materialvetenskap

DOI

10.1115/1.4035996