摘要 |
The invention is a beam (1-1, 2-1, 3-1) that comprises at least three web plates (1-2, 1-4, 1-6, 2-2, 2-4, 2-6, 3-2, 3-4, 3-6) that are connected to a bottom flange (1-10, 1-12, 2-10, 2-12, 3-10, 3-12) and top flange (1-10, 1-12, 2-10, 2-12, 3-10, 3-12). |