Scaffolding is a working platform set up to ensure the smooth progress of each construction process

External scaffolding refers to the scaffolding erected on the periphery of the building. External scaffolding is widely used, and various floor-standing external scaffolding, hanging scaffolding, pick-up scaffolding, hanging scaffolding, etc., are generally erected on the periphery of buildings. External scaffolding is mostly used for external wall masonry, facade decoration and reinforced concrete projects.

Scaffolding is a working platform set up to ensure the smooth progress of each construction process. According to the erection position, it is divided into outer scaffolding and inner scaffolding; according to different materials, it can be divided into wooden scaffolding, bamboo scaffolding, steel pipe scaffolding; Hanging scaffolding, pick-up scaffolding, climbing scaffolding.

Different types of construction use scaffolding for different purposes. Most bridge supports use bowl buckle scaffolding, and some use portal scaffolding. Most of the floor scaffolds used in the construction of the main structure use fastener scaffolds. The vertical distance of the scaffolding 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 is highly variable;

2. The joints connected by fasteners are semi-rigid, and the rigidity of the joints is related to the quality of the fasteners and installation quality, and there is a large variation in the performance of the joints;

3. The scaffolding structure and components have initial defects, such as initial bending and corrosion of rods, erection size error, load eccentricity, etc. are all large;

4. The connection point with the wall has a large variation in the binding of 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 value of the structural resistance multiplied by the adjustment coefficient less than 1 is determined by calibrating with the safety coefficient used in the past. Therefore, the design method adopted in this specification is semi-probabilistic and semi-empirical in nature. It is the basic condition for the design calculation that the scaffold meets the structural requirements specified in this code.