Scaffolding is a working platform constructed to ensure the smooth progress of various construction processes. It is categorized by the location of its setup into external scaffolding and internal scaffolding; by materials into wooden scaffolding, bamboo scaffolding, and steel pipe scaffolding; and by construction form into upright scaffolding, bridge scaffolding, portal 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 main structure construction, the most common type of ground scaffolding is the clamp scaffolding, with the longitudinal spacing of the scaffolding uprights generally being 1.2~1.8m; the transverse spacing is usually 0.9~1.5m.
Comparatively, scaffolding has the following characteristics in working conditions compared to general structures:
1. The load variability is quite significant.
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, rusting, significant dimensional errors in assembly, and uneven loading eccentricities.
4. The connection points to the wall exhibit significant variation in constraint for scaffolding. Research on the above issues lacks systematic accumulation and statistical data, and does not meet the conditions for independent probability analysis. Therefore, the adjustment coefficient, which is multiplied by the structural resistance, is determined by calibrating 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.
