LIQUEFIED GAS TANK STRUCTURE, SHIP, AND FLOATING STRUCTURE

To provide liquefied gas tank structure which allows for increase of a tank volume while suppressing increase of welded parts and increase of a height of center of gravity when stored with liquefied gas, in a MOSS-type liquefied gas tank for storing the liquefied gas, and to provided a ship which allows for compactification of a ship body while securing restoring performance of the ship body, and a floating body structure.SOLUTION: The liquefied gas tank structure is comprised of an upper spherical shell body 21, a cylinder equator portion 22 and a lower spherical shell body 23 that have a relationship in which a radius R1 of the upper spherical shell body 21, a radius R2 of a lower end circular portion 21a of the upper spherical shell body 21, a radius R3 of the lower spherical shell body 23, a radius R4 of an upper end circular portion 23b of the lower spherical shell body 23, a radius R5 of an upper end circular portion 22a of the cylinder equator portion 22, a radius R6 of a lower end circular portion 22b of the cylinder equator portion 22, and a height He of the cylinder equator portion 22, satisfy the following condition that R2 and R5 are set to be over SQRT(R1×R1-0.25×He×He) and less than R1, or equal to R1, and R4 and R6 are set to be over SQRT(R3×R3-0.25×He×He) and less than R3, or equal to R3.SELECTED DRAWING: Figure 4 【課題】液化ガスを貯蔵するＭＯＳＳ型の液化ガスタンクにおいて、溶接個所の増加と、液化ガス貯蔵時の重心高さが高くなるのを抑制しつつ、タンク容積を増加することができて、船体の復原性能を確保しつつ、船体をコンパクト化できる液化ガスタンク構造、船舶、及び、浮体構造物を提供する。【解決手段】上部球殻体２１の半径Ｒ１と、上部球殻体２１の下端円部２１ａの半径Ｒ２と、下部球殻体２３の半径Ｒ３と、下部球殻体２３の上端円部２３ｂの半径Ｒ４と、円筒赤道部２２の上端円部２２ａの半径Ｒ５と、円筒赤道部２２の下端円部２２ｂの半径Ｒ６と，円筒赤道部２２の高さＨｅの関係において、Ｒ２とＲ５をＳＱＲＴ（Ｒ１×Ｒ１-０．２５×Ｈｅ×Ｈｅ）を超えかつＲ１未満、又は、Ｒ１と同じとし、Ｒ４とＲ６をＳＱＲＴ（Ｒ３×Ｒ３-０．２５×Ｈｅ×Ｈｅ）を超えかつＲ３未満、又は、Ｒ３と同じとする。【選択図】図４