| 摘要 |
<p>The platform for a spiral staircase enables the entry and exit point of the stairs to be varied, while maintaining standard values for both tread and riser. With a fixed difference in floor levels in a building and with standard values for both tread and riser for a stairway, only one entry or exit point can be chosen. The platform is designed to overcome this, and is made of standard units. These are segments of a circle, concentric with the central column.</p> |
