浮式平台二 设计载荷与工况

第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Loadings (cont.)
Floating system hulls typically have higher external shell design pressure heads, especially for Spar, TLP, and deep draft semisubmersibles. Pressure and global loads are both control loading conditions for floating system. Depending on the locations, it could be either or both can be control conditions.
第二章 浮式结构强度分析
浮式结构设计基础
ห้องสมุดไป่ตู้2008 2008年5月
Loadings (cont.)
偶然、意外、事故荷载
Drop objects Boat impacts Compartment flooding Machinery vibrations

第二章 浮式结构强度分析
第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
第二章 浮式结构强度分析 Strength Analysis of Floating Structure
第二节 设计载荷 和工况 Structural Design Loading Conditions 闫发锁


第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Loadout Condition (cont.)
Hull loadout is more complicate, and deserve particular attention. Plate structure is typically designed for in-place condition, not these temporary conditions, so the support of loadout has to fit the existing structure. Depending on the loadout system used, the loads on the hull at quay side can be much higher than the loads at lands or on the vessel.
浮式结构设计基础
2008 2008年5月
Loadings (cont.)
Floating structure decks typically have significantly higher design loadings than either fixed production platforms due to the dynamic motion of the system. For the dry tree application, TLP deck normally has much larger loadings because the production risers are tensioned from the deck. On fixed platforms the wells are supported by conductor pipes, not the deck structure, and on drilling semisubmersibles there are no production riser loads. For Spar structure, the riser is typically support on separate buoyancy cans. For wet tree semisubmersibles, SCR is supported on the hull.

第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Transportation Load Condition (cont.)
Design criteria for wet or dry tow of the hull and deck are a function of tow route, duration and time of year. These considerations affect the design storm magnitude and the ability to avoid extreme storms. Additional environmental data for transportation should be provided by the transportation contractor for the particular tow route, conditions and vessels involved.

第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Loadout Condition
Loadout is one of the control conditions for offshore structure. For deck structure, a rigorous loadout structural analysis should be performed to identify areas subject to high localized loading. Such a analysis might be performed assumed relative specified tolerance. A 2” displacement tolerance is a value which most used during loadout. Generally, deck structure in the vicinity of the loadout truss or skid ways, particularly truss joints, will be subjiect to such loadings and may require local strengthening.

第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Transportation Load Condition
The hull may be either wet or dry transported with or without the deck attached. Hull dry-transport is an option for structure fabricated at distant fabrication yards and transportable on presentday vessels where improved towing speed and storm avoidance is desirable. Hull wet tow will be required to meet installation and decommissioning requirements. For the GOM projects, the hull would most likely be fabricated in Asia and dry-towed to an adequate GOM location where the offshore deck mating and outfitting would be completed. The completed TLP would then be wet-towed to the site for installation. If the hull is fabricated at a GOM location, the dry tow condition may or may not be applicable, and thus a wet-tow transportation of the hull alone may beed to be considered.

第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Pre-Service Design Loading Conditions
Deck and hull pre-service structural design loading conditions are similar prior to attaching the deck to the hull and are the same after the deck and hull are mated. Tow conditions normally are different for deck and hull. Wet tow to installation site is used mostly for hull, accompanying by upending in Spar case; while dry tow is often the option to installation site. The following pre-service conditions are typically analyzed.
Wind, current and wave loads Inertial loads from platform acceleration Global space frame stresses from platform response to environment


第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Construction Condition
The hull design construction condition is generally not rigorously analyzed in final design since the hull will usually be constructed in the condition where the imposed construction loads will be much less than in-service design loads. This assumes that good fabrication practices will be implemented in the yard to preclude any unnecessary overstress of the hull structure during construction. The deck design construction condition will be a function of the particular fabricator’s construction capabilities. A rigorous analysis will be required for any major lifts, especially where deck structure load paths are significantly different than for in-service design conditions.
第二章 浮式结构强度分析
浮式结构设计基础
2008 2008年5月
Loadings
结构设计载荷类型:
静态载荷
Dead weight of the steel and outfitting Facilities equipment weight Riser loads Mooring loads
环境载荷及其效应