| 摘要 |
Protruding tread slabs, consisting of a steel frame filled with site concrete, are located on an upright support column, each frame being rigidly joined to a column ring, to make up a spiral staircase. - The shanks (17) of the frame (2) pass through the ring (12) in correspondingly shaped apertures (18). They are held in the inside of the ring by weld joints. The shanks, or attachments welded to them, may be splayed inside the ring, while rings are filled with site concrete, and interlock with each other. Bearing forces, to be conducted from treads to column, are effectively absorbed by the interconnected column rings, but rings need not be thick and heavy.(DS) |
