Civil Engineering Reference
In-Depth Information
The most appropriate means of assessing an individual member for the effect
of a crack of a size allowing flooding is through a fracture mechanics assessment.
A fracture mechanics assessment will determine, for the size of defect, whether
failure by fracture or collapse will occur under the prescribed conditions.
It should first be determined that the member can sustain through-thickness
damage of a size sufficient to cause leakage without failing completely under
the anticipated loading conditions. If this cannot be demonstrated, then FMD is
not a suitable method for ensuring that the member
s integrity is maintained. If
it is determined that through-wall damage is possible but that complete severance
is not, then it is necessary to demonstrate that FMD can detect the flooded condi-
tion before final severance or some other degree of damage is detected over a par-
ticular inspection interval. Given the extreme variability associated with all factors
influencing fracture and collapse performance, a probabilistic fracture mechanics
assessment should be undertaken to establish the probability of failure of an indi-
vidual weld and, ultimately, the probability of failure of a complete member.
An alternative method for predicting failure frequencies is the use of historical
data. There are many studies of a fracture mechanics approach to calculation of the
probability of a member
'
s leaking, and the probability of complete severance. The
studies consider member failure rates obtained from a historical review. It should
also be noted that other analytical approaches, many of them based on fracture
mechanics, may be employed to determine the probability of failure of a member.
'
Final Inspection Reporting
The inspection contractor
'
s final report is submitted upon completion of all
inspection activities.
The format for the final report is:
Title page
●
Report Title/Author/Company/Date, etc.
●
Contents
●
Summary
●
Contractor
'
s name
●
Dates of survey
●
Inspections completed and inspections omitted and reasons for omission
●
Anomalies found
●
Conclusions
●
Outstanding actions
●
Inspection results by area
●
Written summary
●
Inspection datasheets
●
Drawings
●
Anomaly sheets (including NDT reports where available)
●
Photographs/Video stills
●
Operations analysis
●
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