A Study on Stability of Floating Architecture and its Design Methodology

Toshio Nakajima, Waterfront Real Estate Co., Ltd.
Yuka Saito, Building Department, Design Engineering Division (OIL&GAS PROJECT COMPANY, JGC CORPORATION)
Motohiko Umeyama, Department of Civil & Environmental Engineering (Tokyo Metropolitan University)

The overall approach to the design of a floating architecture such as a floating house is described in this paper. The author’s primary aim in writing this paper is not to present some method of stability for floating structures, but rather to provide a method of design synthesis for such structures. An integrated procedure at the preliminary design stage is presented for carrying out systematically the design of floating structures.

In general, the primary concern when designing floating structures centers on avoidance of large tilt due to the heavy environmental loads like wind gust for people onboard the floating platform. In order to prevent such a serious situation for the platform, being able to determine the adequate GM value is useful for maintaining the steady tilt within a permissible limit angle Φ upon the simultaneous existence of all possible environmental forces. Based on this concept, the problem is considered in a general manner and methods used as a practical procedure while introducing a new approach, the so-called the “Required GM” method.

This paper comprises different parts of various aspects for the determination of the basic configuration of a floating architecture; namely, the aspect of the static stability and the overall design process at the conceptual design stage. In addition, illustrative examples are offered as regards an idealized floating platform embodying the simplest possible structure sufficient for illustrating the points discussed.

Keywords – Floating house, Sustainable, Natural hazard, Flood house, Climate change


Dr. Toshio Nakajima has two professional backgrounds: one is
architectural design and the other, offshore engineering. He is a Registered
Architect in Japan and gained a doctorate from Dept. of Naval Architecture
at the University of Tokyo. He is a specialist in the fields of dynamics
regarding offshore floating platforms as well as mooring systems in the
fields of ocean engineering. He has worked at the Kiyonori Kikutake
Architect & Associates as an architectural designer and was a senior
researcher at the Sumitomo Heavy Industries Co., Ltd., among other
positions. He has published numerous research papers especially on a
behavior of semi-submersible platforms in waves over the last 40 years and
was awarded “The Prize for the Most Remarkable Research Paper” from the Society of Naval
Architects of Japan (SNAJ) in 1986. His recent works are related to a semi-floating “Sustainable
Water City” and one of his papers was selected as one of top 100 ground-breaking papers by
Springer-Nature in 2015.

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