| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a building material at a low cost with high strength. SOLUTION: A core member 14 is stored in a facing member 12 constituted by combining a semi-cylindrical first member 16 with a second member 17. The core member 14 is formed of a hollow cylindrical metal such as steel, etc., having strength higher than the facing member 12. The first member 16 and second member 17 are so formed that there is almost no gap between the facing member 12 and core member 14, and the facing member 12 and core member 14 are monolithically formed. The core member 12 is held between the first member 16 and second member 17, and both members are connected to each other to obtain a cylinder 10.</p> |
