Scaffolding is a working platform constructed to ensure the smooth progress of various construction processes. It is categorized by its placement into outer scaffolding and inner scaffolding; by material into wooden, bamboo, and steel pipe scaffolding; and by construction into vertical pole scaffolding, bridge scaffolding, door scaffolding, suspended scaffolding, hanging scaffolding, cantilever scaffolding, and climbing scaffolding.
Different types of construction projects require different types of scaffolding. Bridge supports mostly use bowl coupler scaffolding, with some using portal scaffolding. The main structure construction ground scaffolding mostly uses clamp scaffolding; the longitudinal spacing of the scaffold uprights is generally 1.2~1.8m; the transverse spacing is generally 0.9~1.5m.
Comparatively speaking, scaffolding has the following characteristics in working conditions compared to general structures:
1. The load variability is relatively high.
2. The connection nodes of fasteners are semi-rigid, and the rigidity of the nodes is related to the quality of the fasteners and the installation quality, with significant variation in node performance.
3. Scaffold structures and components have initial defects, such as initial bending of rods, rust, significant setup size errors, and eccentric loading, all of which are considerable.
4. The connection points with the wall exhibit significant variability in their constraint on the scaffolding. Research on the aforementioned issues lacks systematic accumulation and statistical data, and does not meet the conditions for independent probability analysis. Therefore, the adjustment coefficient applied to the structural resistance, which is less than 1, is determined by calibrating it against previously used coefficients. Consequently, the design method adopted in this specification is essentially semi-probabilistic and semi-empirical. Compliance with the structural requirements specified in this specification is a fundamental condition for design calculations.
