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Supplement 1 February Replace the definition for operator with the following:. Operator: the person, firm, corporation, or other organization employed by the owners to conduct operations. Replace the abbreviations with the following:. American Society of Civil Engineers. American Society of Mechanical Engineers. American Institute of Electrical Engineers.
American Society for Testing and Materials. American Petroleum Institute. American Welding Society. American Institute of Steel Construction. International Association of Drilling Contractors. National Fire Protection Association. Offshore Technology Conference. American Concrete Institute. National Association of Corrosion Engineers.
This publication serves as a guide for those who are con- cerned with the design and construction of new platforms and for the relocation of existing platforms used for the drilling, production, and storage of hydrocarbons in off- shore areas. In addition, guidelines are provided for the assessment of existing platforms in the event that it becomes necessary to make a determination of the "fitness for pur- pose" of the structure.
Adequate planning should be done before the actual design is started in order to obtain a workable and economical off- shore platform to perform the given function.
The initial plan- ning should include the determination of all criteria upon which the design or assessment of the platform will be based. Design Criteria. Design criteria as used herein include all operational requirements and environmental criteria that could affect the design of the platform.
Codes and Standards. The operator is defined herein as the person, firm, corpo- ration, or other organization employed by the owners to conduct operations.
Fixed Platforms. A jacket or welded tubular space frame that is designed to serve as a template for pile driving and as lateral bracing for the piles. Piles that permanently anchor the platform to the ocean. A superstructure consisting of the necessary trusses and. The tower may be floated to location and placed in position by selective flooding.
Tower platforms may or may not be supported by piling. Minimum structures include one or more of the. Structural framing, which provides less redundancy than a typical four-leg, template-type platform. Freestanding caisson platform, which consists of one. Well conductor s or freestanding caisson s , which are. Threaded, pinned, or clamped foundation elements piles. This recommended practice does not cover the design of gravity platforms except as included in Section G.
Other Platforms. Primary lateral support is provided by a guyline system. Guyed towers are covered in this practice only to the extent that the provisions are applicable. It is flexible enough that applied forces are resisted in significant part by inertial resis- tances to platform motion.
The result is a reduction in forces transmitted to the platform and the supporting foundation. Guyed towers are normally compliant, unless the guying sys- tem is very stiff. Compliant platforms are covered in this practice only to the extent that the provisions are applicable. The functions for which a platform is to be designed are usually categorized as drilling, producing, storage, materials handling, living quarters, or some combination of these.
When sizing the platform, consideration should be given to equipment operational requirements, such as access, clear- ances, and safety.
The location of the platform should be specific before the design is completed. Design conditions can vary with geo- graphic location. Within a given geographic area, the foun- dation conditions can vary, as can such parameters as design wave heights, periods, tides, currents, marine growth, and earthquake-induced ground motion. The orientation of the platform refers to its position in plan referenced to a fixed direction such as true north.
Ori- entation is usually governed by the direction of prevailing seas, winds, and currents, and by operational requirements. Water Depth. The water depth and tides at the site and surrounding area are needed to select appropriate oceanography design parameters. The water depth should be determined as accu- rately as possible so that elevations can be established for boat landings, fenders, decks, and corrosion protection.
Access and Auxiliary Systems. The location and number of stairways and access boat landings on the platform should be governed by safety con- siderations. A minimum of two accesses to each manned level should be provided, and should be located so that escape is possible under varying wind conditions.
Operating requirements should also be considered in locating stairways. Fire Protection. Personnel safety and possible damage to or loss of the platform require that attention be given to fire protection methods.
The selection of the system depends upon the function of the platform. Procedures should conform to all federal, state, and local regulations where they exist. Deck Elevation. Unless the platform has been designed. An additional generous air gap see Sec- tion C. The clearance between other decks is governed by operational restrictions.
Wells and Risers. Well conductors and riser pipes will result in additional environmental loads on the platform when they are sup- ported by the platform.
Their number, size, and spacing should be known early in the planning stage. Conductor pipes might assist in resisting the wave force. Consideration should be given to the possible need for future wells and risers. Equipment and Material Layouts. Layouts and weights associated with gravity loads as defined in Section C.
Heavy concentrated loads on the platform should be located so that proper framing for supporting these loads can be planned. Consideration should be given to future operations. Personnel and Material Transfer. Plans for transferring personnel and materials should be developed at the start of the platform design.
This planning should consider the type and size of supply vessels and the anchorage system required to hold them in position at the platform; the number, size, and location of the boat landings and fenders; and the type, capacity, number, and location of the deck cranes. If portable equipment or materials are to be placed on a lower deck, then adequately sized hatches should be provided and conveniently located on the upper decks.
The possible use of helicopters should be established and the appropriate facilities provided. Spillage and Contamination. Provision for handling spills and potential contaminants should be provided. A deck drainage system that collects and stores liquids for subsequent handling should be pro- vided. The drainage and collection system should meet applicable government regulations.
Design of all systems and components should anticipate normal as well as extreme environmental phenomena that may be experienced at the site. The following subsections present a general summary of the environmental information that could be required:. Normal oceanographic and meteorological environmen-.
See Section C. Extreme oceanographic and meteorological environmen-. Two levels of earthquake environmental conditions are. Wind forces are exerted upon the portion of the structure that is above the water, as well as on any equipment, deck houses, and derricks, located on the platform. Wind velocities for both extreme and normal conditions are required. Wind-driven waves are a major source of environmental forces on offshore platforms. Such waves are irregular in shape, can vary in height and length, and can approach a platform from one or more directions simultaneously.
For these reasons, the intensity and distribution of the forces applied by waves are difficult to determine. Wave criteria for both extreme and normal conditions are required.
Tides are important in the design of platforms as they affect a the forces on the platform and b the elevations of boat landings, fenders, and deck. Currents are important in the design of platforms as they affect a the forces on the platform and b the location and orientation of boat landings and fenders.
Marine Growth. In most offshore areas, marine growth on submerged platform members is a design consideration.
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API RP2A PRACTICE FOR THE 1990S--A STEP FORWARD
API RP 2A-LRFD:2019-08
Log in to your subscription Username. Peer reviewed only Published between: Published from year: and Published to year: Advanced search Show search help. Rock Mechanics Symposium and 5th U. Authors R. Turner AME Ltd. Ellinas AME Ltd.