Reliability of API and ISO Guidelines for Bearing Capacity of Offshore Shallow Foundations

The safe bearing capacity for offshore shallow foundations has been traditionally assessed using working stress design (WSD) methods (e.g. the API RP 2GEO guideline). Other codes of practice such as the ISO standard strive to provide designs achieving a desired target reliability level in the form of the Load and Resistance Factor Design (LRFD)...

Risk Analysis of Earthquake-Induced Submarine Slope Failure

This paper presents an offshore risk analysis in a systematic manner to assess the influence of earthquake-induced submarine slope failure on offshore structures. The risk analysis is carried out for the future development of a natural gas field in deep waters in the south part of the Gulf of Mexico. The study accounts for all the elements in...

Probabilistic VHM Failure Envelopes for Skirted Foundations in Spatially Variable, Normally Consolidated Clay

Skirted foundations are used in offshore applications to resist the large horizontal and moment loads that are characteristic of the ocean environment. The ultimate capacity of a skirted foundation subjected to vertical-horizontal-moment (VHM) loading combinations can be described using failure envelopes in VHM load space. This represents a far...

Accounting for Uncertainty and Variability in Geotechnical Characterization of Offshore Sites

This paper presents an overview on how uncertainty and variability of mechanical soil properties are dealt with in offshore site investigation and presents some ideas for utilizing the reliability tools in a more optimal manner for this purpose. Two types of problems are addressed. First, how to extract the maximum amount of information from...

Examples of the influence of centrifuge modelling on offshore geotechnical engineering

Offshore geotechnical engineering is characterized by unusual soil and loading conditions, a continuously moving frontier resulting in the requirement for innovative geotechnical solutions, and the very high cost associated with in-situ soil characterization and field testing in remote and deep oceans. As a consequence, offshore engineering...

Waves and their effects on pile-supported structures

Three methods of presenting wave data are discussed: the significant wave (including the "design wave" concept), the wave spectrum, and the directional spectra. Their use in calculating wave forces on pile supported structures is described, with a discussion of the relative usefulness of the linear versus the non-linear approach. The concept of...

The influence of wave forces on the design of offshore structures for the oil industry

Until after the second World War, the ocean was regarded by the oil industry only as a cheap means of transportation. Before the war some timber structures very close to the shoreline had been constructed, but drilling for oil on the continental shelf did not really start until 1947, when the first steel platform was erected in 20 ft. of water...