The electronic pdf versions of the documents found through http://www.dnv.com/ are the officially binding versions. Copyright Det Norske Veritas.
![[Table of Contents]](/dwicons/b_toc.gif)
|
DNV-OS-C502 Offshore Concrete Structures
|
SECTION 3
Design DocumentationSec.3
A. Overall Planning
Sec.3
A 100 General
Sec.3 A
101 A fixed/floating concrete offshore Structure shall
be planned in such a manner that it can meet all requirements related
to its functions and use as well as its structural safety and durability
requirements. Adequate planning shall be done before actual design
is started in order to have sufficient basis for the engineering
and by that obtain a safe, workable and economical structure that
will fulfil the required functions.
Sec.3 A
102 The initial planning shall include determination and description
of all the functions the structure shall fulfil, and all the criteria
upon which the design of the structure are based. Site-specific
data such as water depth, environmental conditions and soil properties
shall be sufficiently known and documented to serve as basis for
the design. All functional and operational requirements in temporary
and service phases as well as robustness against accidental conditions
that can influence the layout and the structural design shall be
considered.
Sec.3 A
103 All functional requirements to the Structure affecting the layout
and the structural design, shall be established in a clear format
such that it can form the basis for the engineering process and
the structural design.
Sec.3 A
104 Investigation of site-specific data such as seabed topography,
soil conditions and environmental conditions shall be carried out
in accordance with requirements of DNV-OS-C101, ISO 19901-1 and
ISO 19901-4.Sec.3
A 200 Description of Offshore Concrete
Structure
Sec.3 A
201 The objective is to provide an overview of the offshore Structure,
highlighting key assumptions and operational phases of the development.
Sec.3 A
202 The overview should be presented in three sections: - Overview of facility
- Development bases and phases
- Staffing philosophy and arrangements.
Cross-references to data sources, figures etc. should be provided.
Sec.3
A 300 Meteorological and ocean conditions
Sec.3 A
301 The objective is to summarise key design parameters with cross-references
to key technical documents.
Sec.3 A
302 The metocean/climatology conditions section should cover
at least the following:| — | storm/wave/current
conditions |
| — | wind |
| — | seawater/air temperature |
| — | earthquakes |
| — | cyclones |
| — | other extreme conditions |
| — | seabed stability |
| — | tsunami |
| — | atmospheric stability |
| — | range and rates of changes of barometer pressure |
| — | rainfall, snow |
| — | corrosive characteristics of the air |
| — | frequency of lightening strikes |
| — | relative humidity. |
Sec.3 A
303 Seismology for Gravity Based Structure in Seismic Active Zones:An earthquake is defined by the horizontal and vertical accelerations
of the ground. These accelerations are described by their:
| — | frequency spectrum |
| — | amplitude. |
Guidance note:
A site specific earthquake analysis shall be performed. This
analysis shall be reported in a Seismic Report where geological
and seismic characteristics of the location of the gravity based
facilities and the surrounding region as well as geotectonic information
from the location have to be taken into account. As a conclusion
this report shall recommend all seismic parameters required for
the design.
The potential of earthquake activity in the vicinity of the
proposed site is determined by investigating the seismic history
of the region (320 km radius) surrounding the site, and relating
it to the geological and tectonic conditions resulting from the
soil survey.
These investigations involve thorough research, review and
evaluation of all historically reported earthquakes that have affected, or
that could reasonably be expected to have affected the site.
The geological, tectonic and seismological studies help to
establish:| - | strength level earthquake (SLE) | - | ductility level earthquake (DLE). | |
---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
SLE and DLE shall be established as either:
| — | probabilistically, as those
that produce ground motions with the mean recurrence as a minimum
interval of 10 000 years for the DLE and 100 years for the SLE,
and/or |
| — | deterministically, assuming that earthquakes which are analogous
to maximum historically known earthquakes are liable to occur in
future with an epicentre position which is the most severe with
regard to its effects in terms of intensity on the site, while remaining
compatible with geological and seismic data. In this case, the SLE
accelerations shall be one-half those determined for the DLE. |
Sec.3
A 400 Layout of the offshore concrete
structure
Sec.3 A
401 The objective is to provide a description of the Offshore Structure,
its unique features (if any), equipment layout for all decks, and
interaction with existing offshore/onshore facilities.
Sec.3 A
402 This section should include a description of at least the following
(where applicable):| — | General:| — | structure/platform | | — | geographical location | | — | water depth. |
|
| — | Layout:| — | orientation of the structure | | — | elevation/plan views | | — | equipment | | — | escape routes | | — | access to sea deck | | — | emergency assembly area etc. | | — | structural details, including modelling of structure
and loadings. |
|
| — | Interaction with existing facilities:| — | physical connections | | — | support from existing facilities. |
|
| — | Interaction with expected facilities (where applicable). |
Sec.3
A 500 Primary functions
Sec.3 A
501 To provide a description of the functions of the Facility by
describing key processes: | — | oil storage system |
| — | pipeline systems |
| — | marine and helicopter operations. |
This information is required as background information essential
for identification of structural hazards of importance for the design
of the structural load bearing structure of the terminal.
Sec.3 A
502 The primary functions section should include a description
of at least the following (where applicable):
Process systems:
| — | process description (overview) |
| — | process control features |
| — | safety control systems for use during emergencies e.g. controls
at the TR or emergency assembly area. |
Oil storage system
| — | oil storage tank |
| — | piping |
| — | layout |
| — | electrical |
| — | monitoring. |
Pipeline and riser systems:
| — | location, separation, protection |
| — | riser connect/disconnect system. |
Utility systems:
| — | power generation and distribution |
| — | communications |
| — | other utility systems (e.g. instrument air, hydraulics, cranes). |
Inert gas systems
| — | safety features (e.g. blow-out
prevention systems) |
| — | integration with platform systems. |
Workover and wireline systems:
| — | extent and type of activity
planned |
| — | integration with platform systems. |
Marine functions/systems:
| — | supply |
| — | standby vessels |
| — | diving |
| — | ballast and stability systems |
| — | mooring systems |
| — | oil/gas offloading system |
| — | oil/gas vessel mooring system. |
Helicopter operations:
| — | onshore base |
| — | capability of aircraft |
| — | helicopter approach. |
Sec.3
A 600 Standards
Sec.3 A
601 A design brief document shall include references to Standards
and design specifications.Sec.3
A 700 Documentation
Sec.3 A
701 Documentation shall be prepared for all activities that shall
be performed in the design, construction, transportation and installation
of offshore concrete structure. Documentation shall also be prepared
showing records of all inspection and control of materials used
and execution work performed that has an impact on the quality of
the final product. The documentation shall be to a standard suitable
for independent verification.
Sec.3 A
702 Necessary procedures and manuals shall be prepared to ensure
that the construction, transportation, installation and in-service
inspection are performed in a controlled manner in full compliance
with all assumptions of the design.
Sec.3 A
703 The most important assumptions, on which the design, construction
and installation work is based with regard to the Offshore Concrete
structure, shall be presented in a Summary Report. The Summary Report
shall be available and suitable for use in connection with operation,
maintenance, alterations and possible repair work. The summary report
will normally be based on the documentation identified in A800 and
A900.Sec.3
A 800 Documentations required prior to
construction
Sec.3 A
801 The technical documentation of concrete structure, available
prior to construction, shall comprise:| — | design calculations for the
complete structure including individual members |
| — | project specification and procedures |
| — | drawings issued for construction and approved by design manager. |
Sec.3 A
802 All technical documentation shall be dated, signed and verified.
Sec.3 A
803 The Project Specification shall comprise:| — | construction drawings, giving
all necessary information such as geometry of the structure, amount
and position of reinforcing and prestressing steel and for precast
concrete elements, tolerances, lifting devices, weights, inserts,
etc. |
| — | description of all products to be used with any requirements
to the application of the materials. This information should be
given on the drawings and/or in the work description. Material
specifications, product standards, etc., shall be included |
| — | work description (procedures) related to the construction activity. |
Sec.3 A
804 The work description should also include all requirements
to execution of the work, i.e. sequence of operation, installation
instructions for embedment plates, temporary supports, work procedures,
etc.
Sec.3 A
805 The work description shall include an erection specification
for precast concrete elements comprising:| — | installation drawings consisting
of plans and sections showing the positions and the connections
of the elements in the completed work |
| — | installation data with the required materials properties
for materials applied at site |
| — | installation instructions with necessary data for the
handling, storing, setting, adjusting, connection and completion
works with required geometrical tolerances |
| — | quality control procedures. |
Sec.3
A 900 AS-BUILT documentation
Sec.3 A
901 The As-Built documentation shall comprise:| — | quality records |
| — | method statements |
| — | sources of materials, material test certificates and/or
suppliers' attestation of conformity, mill certificate,
approval documents |
| — | applications for concessions and responses |
| — | as-built drawings or sufficient information to allow
for preparation of as-built drawings for the entire structure including
any precast elements |
| — | a description of non-conformities and the results of
possible corrective actions |
| — | a description of accepted changes to the project specification |
| — | records of possible dimensional checks at handover |
| — | a diary or log where the events of the construction
process are reported |
| — | documentation of the inspection performed |
| — | Geotechnical Design Report (GDR). |
Sec.3
A 1000 Inspection/monitoring
plans for structure in service
Sec.3 A
1001 Plans for monitoring and inspection of the installation shall
be prepared.
![[-]](/dwicons/i_colpse.gif)