Scaffolding is a work platform designed 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, bamboo, 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 scaffolding uses bowl coupling scaffolding, with some using gate scaffolding as well. For main structure construction, the most common type of ground scaffolding is the clamp scaffolding. The longitudinal spacing of the scaffolding uprights is generally 1.2 to 1.8 meters, and the transverse spacing is usually 0.9 to 1.5 meters.
Scaffolding, compared to general structures, has the following characteristics in terms of working conditions:
1. The load variability is 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, with significant variation in node performance.
3. Scaffold structures and components have initial defects, such as initial bending of rods, corrosion, significant assembly size errors, and loading eccentricities.
4. The connection points to the wall exhibit significant variation in their constraint on the 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 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 semi-probabilistic and semi-empirical. Compliance with the structural requirements specified in this specification is a fundamental condition for design calculations.
