A COMPREHENSIVE STUDY ON THE CONSTRUCTION OF MEGA-FLOATING ARTIFICIAL ISLANDS

本研究旨在对大型浮式构筑物如浮式人工岛屿的建造进行综合研究。结构的大小可能是几公里，其中可能包括浮动机场。Nagao研究了这种浮式结构的抗风设计。为了弄清这一点，他在平面盒截面模型上做了一些实验。计算结果表明，近风特性对风力有显著影响。Kitahara分析了地震作用下的流体-弹性地基-多孔地基系统。所采用的方法是边界元法，三个域分别建模，并在其边界处结合。数值计算结果表明，在降低地应力方面，基础对地面的淹没是有效的。Funaki对大型近海结构进行了悬链线系泊研究，考察了悬链线重量和刚度对悬链线系泊的影响。基于abaqus的瞬态分析结果，对悬链线的非线性效应进行了线性化处理。上田教授研究了由矩形和半圆形组成的浮体结构，并采用源分布法分析了水动力（衍射力和辐射力）。watanabe教授和utsunomiya博士研究了考虑结构弹性变形的大型浮式结构的波浪响应分析。采用有限元法对流体和结构域进行了建模，并将直接频率法应用于波动响应分析。开发了高阶边界元法（HOBEM）程序，并对超大型浮体结构进行了分析。

This study aims at a comprehensive study on the construction of Mega-floating structure such as floating artificial islands. The size of the structure may be several kilo-meters, which may include floating airport.Prof. Nagao studied on the wind resistant design of such a floating structure. In order to clarify it, he performed some experiments on the flat box-sectional models. It has been obtained that the wind force will be significantly affected by the close wind characteristics.Prof. Kitahara analyzed the fluid-elastic foundation-porous ground system subjected to earthquake excitations. The method employed is the Boundary Element Method, and the three domains are separately modeled, and are combined at their boundaries. The numerical results have shown that the submergence of the foundation to the ground will be effective in terms of the reduction of ground stresses.Prof. Funaki studied on large offshore structures moored by catenary lines, and the effect of the weight and stiffness of the catenary lines were examined. The nonlinear effect of the catenary lines are linearized based on the results of transient analysis by ABAQUS.Prof.Ueda studied the floating structure consisting of rectangular and half-circular shapes, and the hydrodynamic forces (diffraction and radiation forces) were analyzed by the source distribution method. The floating bridges were also studied, and the effect of elasticity of the superstructure were examined.Prof.Watanabe and Dr.Utsunomiya studied on the wave response analysis of large floating structure considering elastic deformation of the structure. The fluid and structural domains were both modeled by Finite Element Method, and the direct frequency method has been applied to wave response analysis. The HOBEM (Higher Order Boundary Element Method) program has also been developed, and the VLFS (very Large Floating Structure) has also been analyzed.