Scaffolding is a working platform erected to ensure the smooth progress of various construction processes. According to the erection position, it can be divided into outer scaffolding and inner scaffolding; according to different materials, it can be divided into wooden scaffolding, bamboo scaffolding, and steel pipe scaffolding; according to the structure form, it can be divided into vertical scaffolding, bridge scaffolding, portal scaffolding, suspended scaffolding, Hanging scaffolding, picking scaffolding, climbing scaffolding.
Different types of construction use scaffolding for different purposes. Most bridge support frames use bowl buckle scaffolding, and some use portal scaffolding. The main structure construction floor scaffolds mostly use fastener scaffolds. The vertical distance of the scaffold poles is generally 1.2~1.8m; the horizontal distance is generally 0.9~1.5m.
Compared with the general structure, the working conditions of scaffolding have the following characteristics:
1. The load has great variability;
2. The fastener connection node is semi-rigid, and the rigidity of the node is related to the quality of the fastener and the installation quality, and the performance of the node has a large variation;
3. There are initial defects in the structure and components of the scaffolding, such as the initial bending and corrosion of the rods, the erection size error, and the load eccentricity.
4. The connection point with the wall has a large constraint variation on the scaffolding. The research on the above problems lacks systematic accumulation and statistical data, and does not have the conditions for independent probability analysis. Therefore, the adjustment coefficient of structural resistance multiplied by less than 1 is determined by calibration with the previously adopted safety factor. Therefore, the design method adopted in this specification is essentially half-probability and half-empirical. It is the basic condition of design calculation that the scaffold meets the structural requirements specified in this code.
