טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentHajaj Roy
SubjectEconomic-Engineering Comparative Analysis of Using Very
Large Floating Structures (VLFS) as a Method for
Expanding Coastal Cities
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Yehiel Rosenfeld
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

The vision of cities floating on water was first described by Jules Verne, in his book, Une Ville Flottante (1871). Over the years this vision has become a reality in a few advanced countries, such as Japan and Singapore. The growing need for expansion of the coastal regions was a precipitating factor in the development of floating facilities, such as piers, hotels, fuel storage, bridges, airports and even partially floating cities.

This research focuses on economic and engineering aspects of artificial island, and provides a broad overview of different aspects, including environmental, safety and security. The construction of "Urban Fabric" on Very Large Floating Structures (VLFS) is compared to the current alternative-conventional artificial islands based on soil fill.

The VLFS alternative is based on the Archimedes' principle that the buoyant force applied to an object is equal to the weight of the fluid the object displaces, allowing any mass, depending on the volume submerged, to float. Therefore, construction of concrete cubes, which contain a large space, allows large buildings to float. Obviously, this space should have secondary use, such as parking spaces or storage while still allowing the "cube" to remain afloat.

The second alternative is a conventional artificial islands based on soil filling. The maritime zone is transformed to land area by building under-water walls that define the perimeter of the island and by filling the space created with soil. The water is then "drained away" and the island is created.

The construction of "Urban Fabric" on VLFS can provide efficient and flexible solutions for sustainable urban development. VLFS may provide many advantages in comparison to conventional artificial islands, not only by economic and industrial advantages, but also from the legal perspective.

The most significant advantage of floating structures is their unique ability to harness the water's buoyancy force in order to support the structure itself. Additionally, due to the fact that the structure is floating, it is less sensitive to earthquakes.

As part of the current thesis, a preliminary general plan was created to estimate the cost of building infrastructure for a floating neighborhood of the size of 1,000 hectares, as an extension to a  coastal city. This option is evaluated in comparison to conventional artificial islands, as a second option.

The results of this study show that there are significant advantages to floating islands compared to conventional artificial islands, not only economically, but also due to the legal, security, safety, and real estate aspects. The estimated cost of building a floating island with a total area of 1,000 hectares is 41.2billion NIS, while the estimated cost of a similar conventional artificial island is 58.9billion NIS.

In addition, the construction of floating islands is less time consuming than building a conventional artificial island of equal size which contributes to its economic viability.

In summary, this research explains and compares several aspects of two alternatives for building an artificial island. Though it is less commonly used, the floating island boasts many advantages: economical, legal and environmental.