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 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 supports use bowl clamp scaffolding, with some using door frame scaffolding. For the main structure construction, most use clamp 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 high.
2. The connecting joints of the fasteners are semi-rigid, and the stiffness of the joints is related to the quality of the fasteners and the installation, with considerable variation in joint performance.
3. Scaffold structures and components have initial defects, such as initial bending of rods, rust, significant assembly size errors, and eccentric loading, all of which are considerable.
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, 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 it against coefficients used in the past. Consequently, the design method adopted in this specification is essentially a combination of semi-probabilistic and semi-empirical approaches. Compliance with the structural requirements specified in this specification is a fundamental condition for design calculations.
