טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentWang Gil
SubjectModular Floating Structures (MFS) - Proof of Concept for
Offshore Urban Development
DepartmentDepartment of Civil and Environmental Engineering
Supervisors Professor Yiska Goldfeld
Professor Nitai Drimer
Professor Yehiel Rosenfeld
Full Thesis textFull thesis text - English Version


Abstract

Modular Floating Structures (MFS) can be a vital supplement for coastal cities adapting to rapid global changes, such as rising sea level, storm surges and demographics. The lack of development areas increases the tension between infrastructure needs, urban needs and nature - impacting both growth and quality of life. This study advocates that floating structures can offer a unique avenue to explore new and sustainable ways of addressing these issues. The concept of MFS presents an alternative solution to increase the available land resources in the adjacent marine environment of coastal cities. It offers a technological adaptation that can help mitigate overdevelopment and urban growth limitations. Studies on the legal requirements needed for the realization of such projects has yet been conducted. Therefore, one of the main goals was to define the required statutorily guidelines for preliminary design. This was achieved by synthesizing statutory requirements, building codes and international regulations, encompass by two disciplines: civil engineering and naval architecture. The study proves that this sustainable approach can be easily implemented in calm water - without the interference of waves. Yet its implementation in open water poses greater challenges, particularly in terms of habitability and comfort. Primarily, the focus of this study was on structural and safety aspects (ultimate limit state design), however it demonstrates that the limiting factors for the feasibility of offshore dwelling are occupant comfort criteria (service limit state design). The study further examines the comfort range of a suburban offshore MFS module, by using a novel methodology that reconciles residential comfort criteria with seakeeping. The investigation is performed by characterizing the hydrodynamic structural response and analyzing its compatibility for offshore dwellings. It shows that the MFS module complies to marine regulations, including seakeeping and comfort, but when evaluating its hydrodynamic response to the accepted accelerations in residential buildings, it reaches performance limits at a certain sea state. The study examines the MFS concept in two locations; in mild sea environment near Singapore and open water conditions of the Eastern Mediterranean Sea; in operational weather conditions, and in extreme storms. It is shown that the multi-body MFS configuration has the capability to attenuate the incident waves of short wave periods, where the inner modules are subjected to lower motion amplitude in relation to the outer modules. It is also presented that during extreme storms, the multi-body configuration becomes less effective, and the motion amplitudes of all the modules within the MFS fabric are almost identical. In order to overcome these issues, the study developed and investigated the contribution of special designed MFS-seawall, which provides a substantial wave reduction also in extreme wheatear conditions. To end, this study demonstrates this novel MFS concept vast potential and feasibility for future implementation, in sheltered water and real sea conditions.