Scaffolding is a working platform constructed to ensure the smooth progress of various construction processes. It is categorized by installation location into outer scaffolding and inner scaffolding; by material into wooden scaffolding, bamboo scaffolding, and steel pipe scaffolding; and by construction form 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. Most bridge support structures use bowl clamp scaffolding, with some using gate scaffolding. For the construction of the main structure, most use clip-on scaffolding for ground-level scaffolding; the longitudinal spacing of the scaffolding posts is generally 1.2~1.8m; the transverse spacing is generally 0.9~1.5m.
Comparatively speaking, scaffolding has the following characteristics in terms of working conditions when 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, corrosion, significant installation size errors, and eccentric loading.
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, thus not meeting the conditions for independent probability analysis. Therefore, the value of the adjustment coefficient, which is multiplied by the structural resistance and is less than 1, is determined by calibrating with coefficients used in the past. Consequently, the design method adopted in this specification is essentially a combination of semi-probabilistic and semi-experiential approaches. Compliance with the structural requirements specified in this specification is the basic condition for design calculations.
