Civil Engineering Reference
In-Depth Information
Throughout the duration of the project, the lead structural engineer is
responsible for gathering and recording the weight and center-of-gravity infor-
mation from all disciplines and for generating the weight report. He is also
responsible for reporting the status of the weight and center of gravity for the
platform components, such as topside modules, decks, bridges and others, as
well as for the sub-structure, to each discipline and to the project manager/engineer
on an agreed-upon regular basis.
On the other hand, each discipline, such as electrical, piping, mechanical
and others, is responsible for furnishing all the necessary weight and center-
of-gravity information for equipment and any items associated with their disci-
pline to the lead structural engineer. Each discipline is also responsible for
updating such information at previously agreed-upon regular intervals at least
monthly or when deemed necessary by the lead structural engineer.
Note that realistic weights and weight allowances can be obtained from ven-
dors by specifying in the request for quotation (RFQ) packages that vendors
guarantee, within agreed-upon limits, their quoted weights and center-of-gravity
data when submitting their quotations.
In general, the lead structural engineer is usually responsible for delivering
the weight-control report and should draw management
s attention to any unde-
sirable weight trends or problems and should suggest corrective actions as
appropriate.
'
Classification of Weight Accuracy
The three basic classifications of weight accuracy are as follows. The weight
allowances proposed for each project stage are shown in
Table 5.3
.
Conceptual: This is based on initial estimates, possibly obtained from
past projects. At the end of conceptual design, the structural weight
estimates should be based on the preliminary structure design by weight
take-off.
●
Detailed: This is based on weight take-off and vendor information.
●
Fabrication: This is based on approved drawings and final take-off.
●
Weight information for all items on the platform should be recorded in a man-
ner consistent with the following definition.
Functional weight conditions are:
Dry weight is a single-item weight or the weight of a collection of items
characterized by its dead weight alone. This condition should typically
exclude any operating fluids, spares, maintenance, tools, packing and tem-
porary transportation materials. However, the recorded dry weight of equip-
ment delivered with lubricants or coolants or the like and pre-installed
should be deemed to include such additional weights.
●
Operating weight is the weight of all equipment and bulks, containing all
relevant fluids and supply weights, under normal operating conditions.
●
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