Spiral staircase
A spiral staircase, also known as a helical or spiral design, is a type of staircase that curves around a central axis. While some people may refer to it as any curved staircase, the term "spiral" specifically describes a structure that rotates around a fixed central column. This rotation can be as little as 30 degrees or as much as a full 360-degree turn. Therefore, any staircase that follows a rotational path should technically be considered a spiral staircase. Not all curved staircases are true spirals. Some feature non-rotational curves, such as hyperbolic or parabolic shapes, which do not revolve around a central point. These types of curves often work in conjunction with a rotating element to create a more complex design. When combined, they form what is commonly called a compound curved staircase. However, regardless of the complexity, the general term "spiral staircase" is often used to describe all curved staircases due to their shared aesthetic and functional characteristics. The most visually striking spiral staircases found in halls typically span between 100 to 120 degrees. Their steps gradually narrow from the base to the top, following a ratio of 4:3 at the wider part and 3:2 at the narrower end. In residential settings, the riser height for marble spiral staircases usually ranges from 150 to 170 mm. The narrowest step width should be at least 270 mm, while the widest part should not exceed 480 mm. The overall width of the staircase is generally between 900 mm and 1300 mm. In luxury settings, such as grand halls, the step height should be less than 150 mm, with the narrowest step width not falling below 310 mm. The widest part of the step has no strict limit, but the total width of the staircase is usually above 1300 mm, ideally over 2000 mm. The structural frame of a spiral staircase must be made of either concrete or steel to ensure stability. The stone cladding should follow a smooth, natural curve without abrupt changes, creating the illusion of a single, solid piece of stone. A well-crafted spiral staircase should feel seamless, avoiding any disjointed or artificial appearance. Galvanized outer hexagonal Rivet Nut,304 stainless steel Rivet Nut,Flat Head Rivet Nut, stainless steel Rivet Nut Hebei Quanfang Fastener Co., Ltd , https://www.quanfangfastener.com