Scaffolding is a working platform erected to ensure the smooth progress of each construction process. According to the location of the erection, it can be divided into external scaffolding and internal scaffolding; according to different materials, it can be divided into wooden scaffolding, bamboo scaffolding, and steel pipe scaffolding; according to the structural form, it can be divided into vertical pole scaffolding, bridge scaffolding, portal scaffolding, suspended scaffolding, hanging scaffolding, cantilever scaffolding, and climbing scaffolding. This article brings you the safety technical requirements for the erection of ground-type scaffolding.
Different types of engineering construction use scaffolding for different purposes. Most bridge support frames use bowl buckle scaffolding, and some use portal scaffolding. Most of the ground-type scaffolding for the main structure construction uses fastener scaffolding. The vertical distance of the scaffolding pole is generally 1.2~1.8m; the horizontal distance is generally 0.9~1.5m.
First, basic requirements for the erection of ground-type scaffolding
1) Prepare a special construction plan and approve it.
2) Acceptance signs and warning slogans should be hung on the external frame to ensure neatness and beauty.
3) The surface of the steel pipe should be painted yellow, and the surface of the scissor brace and skirting board should be painted red and white warning paint.
4) The scaffolding should be erected by the construction progress, and the erection height should not exceed two steps above the adjacent wall connection.
Second, frame erection
1. Foundation treatment: The foundation for erecting the frame must be flat and solid, with sufficient bearing capacity; there must be no water accumulation in the erection site.
2. Frame erection:
(1) The support pole pad should meet the bearing capacity requirements. The pad can be a wooden pad with a length of not less than 2 spans, a thickness of not less than 50mm, and a width of not less than 200mm;
(2) The frame must be equipped with longitudinal and transverse sweeping rods. The longitudinal sweeping rod must be installed with a right-angle fastener on the pole no more than 200mm from the bottom end of the steel pipe. The horizontal sweeping rod must be fixed to the vertical pole just below the vertical sweeping rod with a right-angle fastener;
(3) When the vertical pole foundation is not at the same height, the vertical sweeping rod at the high position must be extended two spans to the low position and fixed to the vertical pole. The height difference should not be greater than 1m, and the distance from the vertical pole axis on the upper side of the slope to the slope should not be less than 500mm;
(4) The step distance of the bottom layer of single-row and double-row scaffolding should not be greater than 2m;
(5) Except for the top step of the top layer, the joints of each layer and step of the single-row and double-row scaffolding vertical pole extension must be connected with butt fasteners;
(6) The butt and overlap of the scaffolding vertical poles should meet the following requirements: When the vertical poles are butt-jointed and extended, the butt fasteners of the vertical poles should be arranged alternately. When the vertical poles are overlapped, the overlap length should not be less than 1m and two or more rotating fasteners should be used for fixing. The distance from the edge of the end fastener cover to the pole end should not be less than 100mm.
3. Setting of wall ties
(1) The wall ties should be arranged close to the main node, and the distance from the main node should not exceed 300mm. The wall ties of the double-row steel pipe scaffolding should be connected to the inner and outer rows of vertical poles;
(2) They should be set from the first step of the longitudinal horizontal pole at the bottom layer. When it is difficult to set it there, other reliable measures should be adopted to fix it;
(3) The vertical spacing of the wall ties should not be greater than the floor height of the building, and should not be greater than 4m, and the horizontal distance should not exceed 6m;
(4) Wall ties must be set at both ends of the open double-row scaffolding;
(5) When the wall ties cannot be set at the bottom of the scaffolding, anti-overturning measures should be taken. When erecting a guy brace, it should be made of full-length rods and fixed to the scaffolding with rotating fasteners. The angle with the ground should be between 45° and 60°. The distance from the center of the connection point to the main node should not be greater than 300mm. The guy brace should be removed only after the wall connection is erected;
(6) The scissor brace and wall connection must be erected and removed simultaneously with the external scaffolding. It is strictly forbidden to erect them later or remove them first.
4. Scissor brace setting
(1) For single-row and double-row scaffolding with a height of less than 24 meters, a scissor brace must be set at both ends of the outer facade, and it should be set continuously from bottom to top. The net distance between the middle scissor braces should not be greater than 15 meters.
(2) For double-row scaffolding with a height of more than 24 meters, scissor braces should be set along the entire length and height of the outer facade. Scissor braces must be set in the longitudinal direction. The width of the cross cover shall not exceed 7 vertical poles, and the angle with the horizontal should be 45°~60°.
(3) The inner side of the scissors brace is fastened to the vertical pole at the intersection with a turnbuckle, and the outer side is fastened to the extended part of the small crossbar. The extension of the diagonal rod of the scissors brace should be overlapped or butt-jointed. When overlapped, the overlap length should not be less than 1 meter, and it should be fixed with no less than 3 rotating fasteners.
(4) Horizontal diagonal braces must be set at both ends of the I-shaped and open double-row scaffolding. A horizontal diagonal brace should be set at the corners of the frame and every six spans in the middle of the frame over 24 meters.
5. Frame support
(1) The scaffolding board (bamboo fence, iron fence) should be fully, steadily, and firmly laid, and the distance from the wall should not be greater than 200mm. There should be no gaps and probe boards. The scaffolding board should be set on no less than three horizontal bars. When the length of the scaffolding board is less than 2m, two horizontal bars can be used for support.
(2) The frame must be closed with a dense safety net along the inner side of the outer frame. The safety nets must be firmly connected tightly closed, and fixed to the frame.
Third, acceptance of the scaffold
1. Acceptance stage of scaffolding and its foundation
(1) After the completion of the foundation and before the scaffolding is erected;
(2) Before applying load on the working layer;
(3) After each 6-8 meters of height is erected;
(4) After reaching the design height;
(5) After encountering a strong wind of level 6 or above or heavy rain, and after the frozen area thaws;
(6) Out of service for more than one month.
2. Key points for scaffolding acceptance
(1) Whether the setting and connection of the rods, the structure of the wall connecting parts supports, and door openings meet the requirements;
(2) Whether there is water accumulation in the foundation, whether the base is loose, whether the vertical is suspended, and whether the fastener bolts are loose;
(3) For double-row and full-height scaffolding with a height of more than 24m, and full-height support frames with a height of more than 20m, whether the settlement and verticality deviation of the vertical rods meet the requirements of the technical specifications;
(4) Whether the safety protection measures for the frame meet the requirements;
(5) Whether there is any overload phenomenon, etc.
Fourth, key points of control
1. Prepare a special construction plan for scaffolding erection according to the actual situation of the project, and strictly implement the plan briefing and safety technology briefing system;
2. The personnel who erect the frame must be certified scaffolders and use personal safety protection equipment correctly;
3. When erecting the frame, technical personnel will provide on-site guidance, and safety personnel will supervise the construction;
4. Carry out safety acceptance work promptly;
5. Strengthen safety inspection and monitoring work.
Post time: Dec-04-2024