Different types of construction projects use different types of scaffolding. For bridge support structures, cup-lock scaffolding is most commonly used, although frame scaffolding is also sometimes employed. For main structure construction, ground-based scaffolding primarily uses coupler-type scaffolding. The longitudinal spacing of scaffolding uprights is generally 1.2~1.8m; the transverse spacing is generally 0.9~1.5m.
Compared to general structures, scaffolding has the following characteristics in its working conditions:
1. The load it bears varies considerably;
2. Coupler connections are semi-rigid, and the rigidity of the connections depends on the quality of the couplers and the installation quality, resulting in significant variations in connection performance;
3. The scaffolding structure and components often have initial defects, such as initial bending of members, corrosion, dimensional errors in erection, and eccentric load distribution;
4. The constraint on the scaffolding at connection points with walls varies considerably. The research on the above issues lacks systematic accumulation and statistical data, and the conditions for independent probabilistic analysis are not available. Therefore, the adjustment factor multiplied by the structural resistance by less than 1 is determined by calibration with the previously used safety factor. Thus, the design method adopted in this specification is essentially semi-probabilistic and semi-empirical. Meeting the structural requirements specified in this specification is a fundamental condition for design calculations.
