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 upright pole scaffolding, bridge scaffolding, gate 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 main structure construction, most use clip scaffolding for ground-level scaffolding. The longitudinal spacing of the scaffolding uprights is generally 1.2~1.8m; the transverse spacing is generally 0.9~1.5m.
Scaffolding, compared to general structures, has the following characteristics in terms of working conditions:
1. The load variability is relatively large.
2. The connection nodes of the 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 loading eccentricities.
4. The connection points with the wall exhibit significant variability in their constraint on 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 multiplied by the structural resistance is determined by calibrating with coefficients used in the past. Consequently, the design method adopted in this specification is essentially semi-probabilistic and semi-experiential. Compliance with the structural requirements specified in this specification is a fundamental condition for design calculations.
