Very large floating structure

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A mobile offshore base Floating runway.jpeg
A mobile offshore base

Very large floating structures (VLFSs) or very large floating platforms (VLFPs) are artificial islands, which may be constructed to create floating airports, bridges, breakwaters, piers and docks, storage facilities (for oil and natural gas), wind and solar power plants, for military purposes, to create industrial space, emergency bases, entertainment facilities (such as casinos), recreation parks, mobile offshore structures and even for habitation. Currently, several different concepts have been proposed for building floating cities or huge living complexes. [1] Some units have been constructed and are presently in operation. [2]

Contents

Floating structures offer several advantages over more permanent structures which might extend from the shore into open water:

Overview

VLFSs differ from watercraft in that most or all of the usable area is the top surface instead of the internal (hold) areas. Thus a useful VLFS will cover significant area. It can be constructed by joining the necessary number of floating units together. The design of the floating structure must comport with safety and strength requirements, operating conditions, etc. Steel, concrete (prestressed or reinforced hybrid) or steel-concrete composite materials may be used to build the floating structure. The motion of the floating structure due to wind or wave action must be substantially neutralized, to ensure the safety of people and facilities on a VLFS, and to allow useful activities. VLFSs must be securely moored to the ocean bed. [3]

Classification

Current VLFS designs fall into two categories: semi-submersible, and pontoon.

The semi-submersible-type VLFS has a raised platform above sea level using column tubes; it is more suitable for deployment in high seas with large waves. In open sea, where the waves are relatively large, the semi-submersible VLFS minimizes the effects of waves while maintaining a constant buoyant force. Semi-submersible types are used for petroleum exploration in deep waters. They are fixed in place by column tubes, piles, or other bracing systems.

The pontoon-type VLFS platform rests on the water surface and is intended for deployment in calm waters such as a cove, a lagoon or a harbor. Its basic element is a simple box structure; it usually offers high stability, low manufacturing cost and easy maintenance and repair. The pontoon type is supported by its buoyancy on the sea surface. The pontoon type is flexible compared to other kinds of offshore structures, so that the elastic deformations are more important than their rigid body motions. Thus, hydroelastic analysis is uppermost in designing the pontoon-type VLFS. Together with the motion of the floating structure, the response of the structure to water waves and the impact on the entire fluid domain have to be studied.

Pontoon-type VLFSs are also known in the literature as mat-like VLFSs because of their small draft in relation to the length dimensions. Very large pontoon-type floating structures are often called ‘mega-floats'. As a rule, the mega-float is a floating structure having at least one length dimension greater than 60 metres (200 ft) Horizontally large floating structures can be from 500 to 5,000 metres (1,600 to 16,400 ft) in length and 100 to 1,000 metres (330 to 3,280 ft) in width, with typical thickness of 2 to 10 metres (6.6 to 32.8 ft).

Applications

Many large floating structures have been conceptualized, including a golf course, [4] a farm, [5] and habitable long-term living complexes (seasteading).

Some large floating structures that have been built include floating airports and floating landing platforms for returning rockets.

Floating airport

A Mega-Float floating airport prototype was constructed in Tokyo Bay from 1998 to 1999. [6] It was one kilometer in length and was primarily intended as a test vehicle, to research the loadings and responses of such installations. [7] This project was substituted as a study project to provide more definite information about a proposed floating runway at Kansai International Airport, which was not built (an artificial island was instead constructed to support the runway). However the choice to build an airport on two islands composed of sand landfill has resulted in the Kansai Airport sinking several centimeters per year. (https://www.smithsonianmag.com/air-space-magazine/how-to-save-a-sinking-airport-180968985/)

Floating launch vehicle operations platform

In the 2010s, SpaceX contracted with a Louisiana shipyard to build a floating landing platform for reusable orbital launch vehicles. The platform had an approximately 90 by 50 meters (300 ft × 160 ft) landing pad surface and was capable of precision positioning with diesel-powered azimuth thrusters [8] so the platform can hold its position for launch vehicle landing. This platform was first deployed in January 2015 [9] when SpaceX attempted a controlled descent flight test to land the first stage of Falcon 9 Flight 14 on a solid surface after it was used to loft a contracted payload toward Earth orbit. [10] [11] The platform utilizes GPS position information to navigate and hold its precise position. [12] The rocket landing leg span is 18 m (60 ft) and must not only land within the 52 m (170 ft)-wide barge deck, but must also deal with ocean swells and GPS errors. SpaceX CEO Elon Musk first displayed a photograph of the "autonomous spaceport drone ship" in November 2014. The ship is designed to hold position to within 3 meters (9.8 ft), even under storm conditions. [13]

On 8 April 2016, the first stage of the rocket that launched the Dragon CRS-8 spacecraft, successfully landed on the drone ship named Of Course I Still Love You, the first successful landing of a rocket booster on a floating platform. [14]

As of 2018, Blue Origin is intending to make the first stage boosters of New Glenn be reusable, and recover launched boosters downrange on the Atlantic Ocean via a ship that is underway acting as a floating movable landing platform. The hydrodynamically-stabilized ship increases the likelihood of successful recovery in rough seas. [15]

Floating parking garage

P-Arken [sv], a floating garage moored in Gothenburg, Sweden Goteborg P-arken.jpg
P-Arken  [ sv ], a floating garage moored in Gothenburg, Sweden

A concept has been patented for a floating automotive parking barge with angled sides to deflect wind shear. [16]

Floating LNG production facility

The Shell floating LNG plant was constructed to process and liquify offshore natural gas into liquified natural gas for transport and storage. [17] [18] The Shell project was scheduled to begin processing gas in 2016. [19] In December 2018, Shell announced that the wells have been opened and the plant was ready to begin the initial phase of production. [20] In June 2019, it reached a significant milestone, shipping its first liquefied natural gas cargo to customers in Asia. [18]

See also

Related Research Articles

<span class="mw-page-title-main">Oil platform</span> Offshore ocean structure with oil drilling and related facilities

An oil platform is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms will also have facilities to accommodate the workers, although it is also common to have a separate accommodation platform linked by bridge to the production platform. Most commonly, oil platforms engage in activities on the continental shelf, though they can also be used in lakes, inshore waters, and inland seas. Depending on the circumstances, the platform may be fixed to the ocean floor, consist of an artificial island, or float. In some arrangements the main facility may have storage facilities for the processed oil. Remote subsea wells may also be connected to a platform by flow lines and by umbilical connections. These sub-sea facilities may include one or more subsea wells or manifold centres for multiple wells.

<span class="mw-page-title-main">Offshore construction</span> Installation of structures and facilities in a marine environment

Offshore construction is the installation of structures and facilities in a marine environment, usually for the production and transmission of electricity, oil, gas and other resources. It is also called maritime engineering.

<i>Iolair</i> Ship

Iolair is a specialised semi-submersible offshore platform designed for BP to support and service oil platforms in the North Sea and served as an emergency support vessel (ESV) in the Forties Oil Field. Since 2000 it has been working in the Cantarell Field, Mexico as an offshore construction and maintenance service vessel operated by Cotemar S.A de C.V.

<span class="mw-page-title-main">Semi-submersible platform</span> Marine vessel used in offshore roles with good stability and seakeeping

A semi-submersible platform is a specialised marine vessel used in offshore roles including as offshore drilling rigs, safety vessels, oil production platforms, and heavy lift cranes. They have good ship stability and seakeeping, better than drillships.

<span class="mw-page-title-main">Mobile offshore base</span> Naval self-propelled moving platform

Mobile offshore base (MOB), sometimes called a joint mobile offshore base (JMOB), is a concept for supporting military operations beyond the home shores, where conventional land bases are not available, by deploying on the high seas or in coastal waters, in-theater multipurpose floating base assembled from individual platforms. In essence, a MOB is a multipurpose modular self-propelled floating platform, or several interconnected platforms, that can perform multiple functions of a sea base including strike, deployment and logistics. An ocean-wise semi-submersible wave and wind resistant platform capable of moving at one-half the speed of conventional prepositioning monohull cargo ship has been researched and proposed, but never built.

<span class="mw-page-title-main">Floating airport</span> Infrastructure concept

A floating airport is an airport built and situated on a very large floating structure (VLFS) located many miles out at sea utilizing a flotation type of device or devices such as pneumatic stabilized platform (PSP) technology.

A Pneumatic stabilized platform (PSP) is a technology used to float a very large floating structure (VLFS).

<span class="mw-page-title-main">Offshore drilling</span> Mechanical process where a wellbore is drilled below the seabed

Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum that lies in rock formations beneath the seabed. Most commonly, the term is used to describe drilling activities on the continental shelf, though the term can also be applied to drilling in lakes, inshore waters and inland seas.

<span class="mw-page-title-main">Jackup rig</span> Type of mobile platform

A jackup rig or a self-elevating unit is a type of mobile platform that consists of a buoyant hull fitted with a number of movable legs, capable of raising its hull over the surface of the sea. The buoyant hull enables transportation of the unit and all attached machinery to a desired location. Once on location the hull is raised to the required elevation above the sea surface supported by the sea bed. The legs of such units may be designed to penetrate the sea bed, may be fitted with enlarged sections or footings, or may be attached to a bottom mat. Generally jackup rigs are not self-propelled and rely on tugs or heavy lift ships for transportation.

<span class="mw-page-title-main">Floating wind turbine</span> Type of wind turbine

A floating wind turbine is an offshore wind turbine mounted on a floating structure that allows the turbine to generate electricity in water depths where fixed-foundation turbines are not feasible. Floating wind farms have the potential to significantly increase the sea area available for offshore wind farms, especially in countries with limited shallow waters, such as Spain, Portugal, Japan, France and the United States' West Coast. Locating wind farms further offshore can also reduce visual pollution, provide better accommodation for fishing and shipping lanes, and reach stronger and more consistent winds.

Offshore concrete structures, or concrete offshore structures, are structures built from reinforced concrete for use in the offshore marine environment. They serve the same purpose as their steel counterparts in oil and gas production and storage. The first concrete oil platform was installed in the North Sea in the Ekofisk oil field in 1973 by Phillips Petroleum, and they have become a significant part of the marine construction industry. Since then at least 47 major concrete offshore structures have been built.

<span class="mw-page-title-main">Float (nautical)</span> Flotation device

Floats are airtight hollow structures, similar to pressure vessels, designed to provide buoyancy in water. Their principal applications are in watercraft hulls, aircraft floats, floating piers, pontoon rhinos, pontoon bridges, and marine engineering applications such as salvage.

A submersible drilling rig is a marine vessel design that can be floated to location and lowered onto the sea floor for offshore drilling activities.

<span class="mw-page-title-main">SpaceX reusable launch system development program</span> Effort by SpaceX to make rockets that can fly multiple times

SpaceX has privately funded the development of orbital launch systems that can be reused many times, similar to the reusability of aircraft. SpaceX has developed technologies over the last decade to facilitate full and rapid reuse of space launch vehicles. The project's long-term objectives include returning a launch vehicle first stage to the launch site within minutes and to return a second stage to the launch pad, following orbital realignment with the launch site and atmospheric reentry in up to 24 hours. SpaceX's long term goal would have been reusability of both stages of their orbital launch vehicle, and the first stage would be designed to allow reuse a few hours after return. Development of reusable second stages for Falcon 9 was later abandoned in favor of developing Starship, however, SpaceX developed reusable payload fairings for the Falcon 9.

<span class="mw-page-title-main">SpaceX CRS-6</span> 2015 American resupply spaceflight to the ISS

SpaceX CRS-6, also known as SpX-6, was a Commercial Resupply Service mission to the International Space Station, contracted to NASA. It was the eighth flight for SpaceX's uncrewed Dragon cargo spacecraft and the sixth SpaceX operational mission contracted to NASA under a Commercial Resupply Services contract. It was docked to the International Space Station from 17 April to 21 May 2015.

<span class="mw-page-title-main">Falcon 9 first-stage landing tests</span> Proofs of the SpaceX boosters reusability

The Falcon 9 first-stage landing tests were a series of controlled-descent flight tests conducted by SpaceX between 2013 and 2016. Since 2017, the first stage of Falcon 9 rockets are routinely landed if the performance requirements of the launch allow.

Autonomous spaceport drone ship Floating landing platform operated by SpaceX

An autonomous spaceport drone ship (ASDS) is a modified ocean-going barge equipped with propulsion systems to maintain precise position and a large landing platform. SpaceX developed these vessels to recover the first stage of its launch vehicles. By recovering and reusing these boosters, SpaceX has significantly reduced the cost of space launch.

<span class="mw-page-title-main">R. Cengiz Ertekin</span> Turkish marine engineer

R. Cengiz Ertekin is a professor of Marine Hydrodynamics and Ocean Engineering. He currently holds a guest professor position at Harbin Engineering University of China. He is best known for his contributions to the development of nonlinear water wave theories, hydroelasticity of very large floating structures (VLFS), wave energy, and tsunami and storm impact on coastal bridges. He is also the co-developer, along with Professor H. Ronald Riggs of the University of Hawaiʻi, of the computer program HYDRAN for solving linear fluid-structure interaction problems of floating and fixed bodies.

Ocean development refers to the establishing of human activities at sea and use of the ocean, as well as its governance.

A floating launch vehicle operations platform is a marine vessel used for launch or landing operations of an orbital launch vehicle by a launch service provider: putting satellites into orbit around Earth or another celestial body, or recovering first-stage boosters from orbital-class flights by making a propulsive landing on the platform.

References

  1. ↑ "DeltaSync floating city". Deltasync.nl. Retrieved 27 October 2014.
  2. ↑ Japan constructed the Mega-Float (a floating runway in Tokyo bay); Japan also has floating fuel storage bases at Shirashima and Kamigoto Islands, and floating ferry piers at Ujina port (Hiroshima). Several very long floating bridges are currently in use; three are located near Seattle, Washington USA. The Floating Bridge, Dubai, over the Dubai Creek, is 300 meters long. Singapore built the world’s largest floating performance stage at the Marina Bay, and is currently installing a mega floating fuel storage facility off Pulau Sebarok. South Korea is currently installing three floating islands on the Han River, to be used for convention centers, and another project at Seoul will function as hotel/convention center/customs site/quay. Science Direct, Very Large Floating Structures, p. 63
  3. 1 2 Wang, C.M.; Tay, Z.Y. (2011). "Very Large Floating Structures: Applications, Research and Development". Procedia Engineering. 14: 62–72. doi: 10.1016/j.proeng.2011.07.007 .
  4. ↑ Kiniry, Laura. "9 of the World's Weirdest Floating Structures: floating golf course" . Retrieved 28 October 2014.
  5. ↑ Kiniry, Laura. "9 of the World's Weirdest Floating Structures: floating farm" . Retrieved 28 October 2014.
  6. ↑ Very large floating structure — Mega-Float, completed 1999. New Atlantis 2002, retrieved 1 October 2011
  7. ↑ Areas being studied in Mega-Float include the hydroelastic behavior of the unit, the mooring system response and durability, the connector system and its welded joints, the anti-corrosion system, the unit's effect on the surrounding sea waves which impact the nearby shoreline, and the unit's effect on the bay's prevailing currents, water quality, and marine ecosystems.
  8. ↑ "SpaceX Announces Spaceport Barge Positioned by Thrustmaster's Thrusters". Thrustmaster. 22 November 2014. Archived from the original on 7 December 2014. Retrieved 23 November 2014.
  9. ↑ Bergin, Chris (17 December 2014). "SpaceX confirms CRS-5 launch slip to 6 January". NASASpaceFlight.com. Retrieved 18 December 2014.
  10. ↑ Foust, Jeff (25 October 2014). "Next Falcon 9 Launch Could See First-stage Platform Landing". Space News. Archived from the original on 25 October 2014. Retrieved 25 October 2014.
  11. ↑ Bullis, Kevin (25 October 2014). "SpaceX Plans to Start Reusing Rockets Next Year". MIT Technology Review. Archived from the original on 25 October 2014. Retrieved 26 October 2014.
  12. ↑ Dean, James (24 October 2014). "SpaceX to attempt Falcon 9 booster landing on floating platform" . Retrieved 27 October 2014.
  13. ↑ Musk, Elon (22 November 2014). "Autonomous spaceport drone ship". SpaceX. Retrieved 23 November 2014.
  14. ↑ "SpaceX Rocket Makes Spectacular Landing on Drone Ship". Phenomena. 8 April 2016. Archived from the original on 20 April 2016. Retrieved 10 April 2016.
  15. ↑ Burghardt, Thomas (20 September 2018). "Building on New Shepard, Blue Origin to pump a billion dollars into New Glenn readiness". NASASpaceFlight.com . Retrieved 22 September 2018.
  16. ↑ Liollio, Zachary. "10,472,024 Floating parking barge for vehicles". USPTO Patent Full-Text and Image Database. U.S. Patent & Trademark Office. Archived from the original on 1 January 2020. Retrieved 19 February 2021.
  17. ↑ "Shell floating LNG technology chosen by joint venture for Greater Sunrise project - Shell Worldwide". Shell.com. Archived from the original on 29 May 2011. Retrieved 10 June 2011.
  18. 1 2 "Prelude FLNG". www.shell.com. Retrieved 19 September 2019.
  19. ↑ Kelly, Ross (19 June 2014). "GDF Suez, Santos Halt Innovative LNG Plan in Australia: Companies Say Offshore Conversion Project Not Commercially Viable". Wall Street Journal. Retrieved 30 December 2014. The decision highlights the risks confronting Australian gas-export projects as they grapple with high costs and competition from North America and Russia, which are vying to provide Asian utilities with cleaner-burning fuels. Confidence in "floating" liquefied natural gas may also be diminishing—two years before a Royal Dutch Shell PLC-owned vessel is due to begin processing gas for the first time.
  20. ↑ "Prelude starts production". www.shell.com.au. Retrieved 19 September 2019.
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