Risk-Based Inspection Technique - Offshore Structures: Design, Construction and Maintenance - page 625

Assessment information

SIM assessment
category

Above water
Underwater
Soil

Assessment
data

Assessment method

Ye s

Wave in deck

Assessment criteria:
Design level
Ultimate strength
Environmental load

No

Simple method

Design level
method

Ultimate
strength

RSR criteria

Alternative
method

Mitigation

No

Pass assessment? Mitigate

Ye s
Document

FIGURE 8.10 Assessment process.

there is any concern that a simple method does not meet the requirements dis-
cussed here, then a more detailed assessment approach should be used.
There are three basic types of simple methods:
The design-level method and ultimate strength method use simple proce-
dures provided that such procedures have been validated. Several investigators
have developed simplified procedures for the evaluation of the adequacy of exist-
ing platforms. Successful use of these procedures requires intimate knowledge of
the assumptions upon which they were based.
The results from previous analyses for the platform are used provided that
the analysis is representative of the platform ' s condition at the time of the

assessment trigger.
Comparison with a similar platform uses assessment results available
from a similar platform.

Design-Level Method (DLM)
DLM involves linear analysis using the standard API RP2A approach for new
platform design by checking the platform on a component basis. The same
factors of safety used for new design are used for DLM. The key difference