| 摘要 |
The joist comprises sections of continuous and drawn metal material and is formed as a single piece by roll, plasma or laser cutting and roll forming or form pressing sheet metal. The drawn metal sections adjoin continuous metal sections on at least one side and at least part of the drawn metal section is pleated to form a V or wave shape extending in the length or cross-direction, so that the peaks and troughs extend above and below the plane of the drawn metal section. |
