Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Very large floating structures

3,777 views

Published on

BRIEF OUTLINE,DESIGN CHART

Published in: Engineering

Very large floating structures

  1. 1. VERY LARGE FLOATING STRUCTURES: APPLICATIONS AND DESIGN ASPECTS ARUNSREENATH A K OFFSHORE STRUCTURES M150152CE
  2. 2. INTRODUCTION  Very large floating structures are manmade islands, which may be constructed to create floating airports, storage facilities (for oil & natural gas), for military purposes ,to create industrial purposes  They are easy and fast to construct  VLFS’S can easily transported,removed,expanded  Cost effective when water depth is large  Do not damage marine eco-system  Do not disrupt ocean currents  They are immune to seismic shock 10 November 2016 CE6397 Very large floating structures:applications and design aspects 2
  3. 3. To classify according to their geometry: I. Pontoons. II. Semisubmersibles. To classify them by location: I. CoastalVLFS. Mega float II. OffshoreVLFS Mobile offshore base(MOB) Pneumatically stabilized platform(PSP) 10 November 2016 CE6397 Very large floating structures:applications and design aspects 3
  4. 4. MEGA FLOAT 10 November 2016 CE6397 Very large floating structures:applications and design aspects 4
  5. 5.  Very large pontoon floating structure  Suitable for use in calm water  Provide break water if significant wave height is greater than 4m  Strong, reliable, lightweight  Construction carried out with modules made on land between 100 and 300 m in length 10 November 2016 CE6397 Very large floating structures:applications and design aspects 5
  6. 6. Advantages  Manufacturing and assembly easy and inexpensive  Unlimited size  Capacity of positive load Disadvantages  suitable for inlets and bays  Low mobility  Ingress of water on deck 10 November 2016 CE6397 Very large floating structures:applications and design aspects 6
  7. 7. Mobile offshore base 10 November 2016 CE6397 Very large floating structures:applications and design aspects 7
  8. 8.  To support military operations wherever convention all and bases are not available  Providing a landing/takeoff area and maintenance, as well as supply and other advanced logistical, support operations  Length of each module : 220 - 500 m  width of each module : 120 - 170 m  Numbers of each module : 3 - 5  Total length of module completely aligned:upto 2km 10 November 2016 CE6397 Very large floating structures:applications and design aspects 8
  9. 9.  Alignment is maintained by Dynamic positioning thrusters  Two types Joint Mobile Offshore Base Hybrid Mobile Offshore Base 10 November 2016 CE6397 Very large floating structures:applications and design aspects 9 Joint Mobile Offshore Base module five semi-submersible steel propelled ships Track - mile(1800m)-long connected with non-load bearing structures A lightweight, collapsible draw bridge allows for transfer between modules.
  10. 10.  Hybrid Mobile Offshore Base  high strength, light weight LWC60 concrete in the steel hull and superstructure deck  fatigue is a major pitfall for a concrete hull with a design life of 100 years. 10 November 2016 CE6397 Very large floating structures:applications and design aspects 10 MOB semisubmersible hybrid concept: four modules together (left) and a single module (right)
  11. 11. Advantages  Mobility.  Suitable for all types of water  Deep and shallow waters  Benign and harsh (conditions good behaviour at sea). Disadvantages  Payload is limited, as is the case with all semisubmersible vessels.  Large internal movements: danger of fatigue in the structure  Connector technology still experimental.  High construction and operational costs 10 November 2016 CE6397 Very large floating structures:applications and design aspects 11
  12. 12. Pneumatically stabilized platform(psp) 10 November 2016 CE6397 Very large floating structures:applications and design aspects 12
  13. 13.  Number of cylindrical components packaged in a rectangular shape to form single module  Each cylinder is sealed at the top and open to the sea at it’s base  It can handle loads and attenuate the wave  Post tensioned cables used to help assemble the components 10 November 2016 CE6397 Very large floating structures:applications and design aspects 13
  14. 14. Advantages  Manufacturing and installation process simple and inexpensive  Suitable for all types of water  Unlimited size (modular)  Low or almost zero maintenance Disadvantages  Experimental technology in its most basic principles: indirect displacement.  Joining technology with tensors in need of extensive further development and study.  Low mobility 10 November 2016 CE6397 Very large floating structures:applications and design aspects 14
  15. 15. APPLICATIONS OF VLFS  FLOATING AIRPORTS The first sizeable floating runway one-km long Mega-Float Mega-Float in Tokyo Bay, Japan (1998) 10 November 2016 CE6397 Very large floating structures:applications and design aspects 15
  16. 16. MOBILE OFFSHORE BASE  large aircraft and ships may support littoral combat operations from a secure position without reliance on achieving political support in other nations 10 November 2016 CE6397 Very large floating structures:applications and design aspects 16 MOB,CHINA
  17. 17. FLOATING STORAGE FACILITIES  used for storing fuel and keeping the explosive, inflammable fluid from populated areas on land.  pontoon structure  Japan has two major floating oil storage systems. in Shirashima with a capacity of 5.6 million kilolitres in Kamigoto with a capacity of 4.4 million kilolitres. 10 November 2016 CE6397 Very large floating structures:applications and design aspects 17
  18. 18. Kamigoto Floating Oil Storage Base,Japan ( 4.4million kilolitres) 10 November 2016 CE6397 Very large floating structures:applications and design aspects 18
  19. 19. FLOATING DOCKS, PIERS, BERTHS AND CONTAINER TERMINALS The floating pier is 150 m x 30 m x4 m. must allow smooth loading and unloading of cars equal tidal rise and fall of the pier and ferries is advantageous Floating Pier at Ujina, Japan 10 November 2016 CE6397 Very large floating structures:applications and design aspects 19
  20. 20. FLOATING EMERGENCY BASES inherently base isolated from earthquakes floating emergency rescue bases in earthquake prone countries Japan has a number of such floating rescue bases Emergency Rescue Base, Tokyo Bay10 November 2016 CE6397 Very large floating structures:applications and design aspects 20
  21. 21. FLOATING BRIDGES 1246-m long Nordhordland Floating Bridge built in1994 at Salhus over a fjord depth of 500 m. bridges are horizontally curved to better resist the wave, the water current and wind forces 10 November 2016 CE6397 Very large floating structures:applications and design aspects 21 Nordhordland Floating Bridge, Norway
  22. 22. Analysis and Design of Floating Structures Characteristics to be considered :  Horizontal forces due to waves much times greater than the (non- seismic) horizontal loads on land-based structures  In framed, tower-like structures the horizontal wave forces produce extreme bending and overturning moments  In a floating structure the static vertical self-weight and payloads are carried by buoyancy.  A particular type of structural system, denoted tension- leg system, is achieved if a highly pre-tensioned mooring system is applied. 10 November 2016 CE6397 Very large floating structures:applications and design aspects 22
  23. 23.  Sizing of the floating structure and its mooring system depends on its function  VLFS’s usually constructed at shore-based building sites remote from the deepwater installation area and without extensive preparation of the foundation.  Owing to the corrosive sea environment, floating structures have to be provided with a good corrosion protection system  Possible degradation due to corrosion or crack growth (fatigue) requires a proper system for inspection, monitoring, maintenance and repair during use. 10 November 2016 CE6397 Very large floating structures:applications and design aspects 23
  24. 24. LOAD TYPES AND COMBINATIONS 1) Permanent or dead loads 2) Variable or live loads 3) Frequent and Rare Environmental loads 4) operation loads 5) Cyclic loads 6) Accidental loads 10 November 2016 CE6397 Very large floating structures:applications and design aspects 24
  25. 25. DESIGN PROCEDURE 10 November 2016 CE6397 Very large floating structures:applications and design aspects 25
  26. 26. DESIGN PROCEDURE 10 November 2016 CE6397 Very large floating structures:applications and design aspects 26
  27. 27. UNIQUENESS OF VLFS 1) Large Size 2) Environment Condition 3) Design and Analysis 4) Connection at Sea 5) Positioning 10 November 2016 CE6397 Very large floating structures:applications and design aspects 27
  28. 28. CONCLUSION  VLFS is a unique concept of ocean structures because of their length,displacement,cost  Requires massive investment and considered as a mega project  Cost of shore facilities is soaring , so offshore floating facilities will become more attractive  21 century there will undoubtedly be significant developments in the field of VLFS 10 November 2016 CE6397 Very large floating structures:applications and design aspects 28
  29. 29. REFERENCES  Miguel Lamas-Pardo a,1, GregorioIglesias b,2, LuisCarral a,3,2015, A review of Very Large Floating Structures (VLFS) for coastal and offshore uses, Ocean Engineering109(2015)677–690  Wanga C.M, Taya Z.Y,2011, Very Large Floating Structures: Applications, Research and Development, Procedia Engineering 14 (2011) 62–72  Masahiko Fujikubo,2005, Structural analysis for the design of VLFS, Marine Structures 18 (2005) 201–226 10 November 2016 CE6397 Very large floating structures:applications and design aspects 29
  30. 30. THANK YOU…. 10 November 2016 CE6397 Very large floating structures:applications and design aspects 30

×