1. General Provisions
1.0.1 This specification is formulated to ensure the safety and applicability of construction scaffolding.
1.0.2 The selection, design, erection, use, dismantling, inspection, and acceptance of materials and components of construction scaffolding must comply with this specification.
1.0.3 Scaffolding should be stable and reliable to ensure the smooth implementation and safety of engineering construction, and should follow the following principles:
① Comply with national policies on resource conservation and utilization, environmental protection, disaster prevention and mitigation, emergency management, etc.;
② Ensure personal, property, and public safety;
③ Encourage technological innovation and management innovation of scaffolding.
1.0.4 Whether the technical methods and measures adopted in engineering construction meet the requirements of this specification shall be determined by the relevant responsible parties. Among them, innovative technical methods and measures shall be demonstrated and meet the relevant performance requirements in this specification.
2. Materials and components
2.0.1 The performance indicators of scaffolding materials and components shall meet the needs of scaffolding use, and the quality shall meet the provisions of relevant national standards in force.
2.0.2 Scaffolding materials and components should have product quality certification documents.
2.0.3 The rods and components used in the scaffolding should be used in conjunction with each other and should meet the requirements of the assembly method and structure.
2.0.4 Scaffolding materials and components should be inspected, classified, maintained, and serviced promptly during their service life. Unqualified products should be scrapped promptly and documented.
2.0.5 For materials and components whose performance cannot be determined through structural analysis, appearance inspection, and measurement inspection, their stress performance should be determined through tests.
3. Design
3.1 General provisions
3.1.1 The scaffolding design should adopt the limit state design method based on probability theory and should be calculated using the partial factor design expression.
3.1.2 The scaffolding structure should be designed according to the ultimate state of bearing capacity and the limit state of normal use.
3.1.3 The scaffolding foundation shall comply with the following provisions:
① It shall be flat and solid, and shall meet the requirements of bearing capacity and deformation;
② Drainage measures shall be set up, and the erection site shall not be waterlogged;
③ Anti-freeze heave measures shall be taken during winter construction.
3.1.4 The strength and deformation of the engineering structure supporting the scaffolding and the engineering structure to which the scaffolding is attached shall be verified. When the verification cannot meet the safety-bearing requirements, corresponding measures shall be taken according to the verification results.
4. Load
4.2.1 The loads borne by the scaffolding shall include permanent loads and variable loads.
4.2.2 The permanent loads of the scaffolding shall include the following:
① The dead weight of the scaffolding structure;
② The dead weight of the accessories such as scaffolding boards, safety nets, railings, etc.;
③ The dead weight of the objects supported by the supporting scaffolding;
④ Other permanent loads.
4.2.3 The variable load of the scaffolding shall include the following:
① Construction load;
② Wind load;
③ Other variable loads.
4.2.4 The standard value of the variable load of the scaffolding shall comply with the following provisions:
① The standard value of the construction load on the working scaffolding shall be determined according to the actual situation;
② When two or more working layers are working on the working scaffolding at the same time, the sum of the standard values of the construction load of each operating layer in the same span shall not be less than 5.0kN/m2;
③ The standard value of the construction load on the supporting scaffolding shall be determined according to the actual situation;
④ The standard value of the variable load of the equipment, tools and other items moving on the supporting scaffolding shall be calculated according to their weight.
4.2.5 When calculating the standard value of the horizontal wind load, the pulsation amplification effect of the wind load shall be taken into account for special scaffolding structures such as high-rise tower structures and cantilever structures.
4.2.6 For the dynamic load on the scaffold, the deadweight of the vibrating and impacting objects shall be multiplied by the dynamic coefficient of 1.35 and then included in the standard value of the variable load.
4.2.7 When designing the scaffold, the loads shall be combined according to the calculation requirements of the ultimate limit state of bearing capacity and the ultimate limit state of normal use, and the most unfavorable load combination shall be taken according to the loads that may appear on the scaffold at the same time during normal erection, use or dismantling.
4.3 Structural design
4.3.1 The design calculation of the scaffold shall be carried out according to the actual construction conditions of the project, and the results shall meet the requirements for the strength, rigidity, and stability of the scaffold.
4.3.2 The design and calculation of the scaffolding structure should select the most representative and unfavorable rods and components according to the construction conditions, and use the most unfavorable section and the most unfavorable working condition as the calculation conditions. The selection of the calculation unit should comply with the following provisions:
① The rods and components with the largest force should be selected;
② The rods and components with the change of span, spacing, geometry, and load-bearing characteristics should be selected;
③ The rods and components with the change of frame structure or weak points should be selected;
④ When there is a concentrated load on the scaffolding, the rods and components with the largest force within the range of the concentrated load should be selected.
4.3.3 The strength of the scaffolding rods and components should be calculated according to the net section; the stability and deformation of the rods and components should be calculated according to the gross section.
4.3.4 When the scaffolding is designed according to the ultimate state of bearing capacity, the basic load combination and material strength design value should be used for calculation. When the scaffolding is designed according to the limit state of normal use, the standard load combination and deformation limit should be used for calculation.
4.3.5 The allowable deflection of the bending members of the scaffolding shall comply with relevant regulations.
Note: l is the calculated span of the bending member, and for the cantilever member it is twice the cantilever length.
4.3.6 The formwork-supported scaffolding shall be designed and calculated for continuous support according to the construction conditions, and the number of support layers shall be determined according to the most unfavorable working conditions.
4.4 Construction requirements
4.4.1 The construction measures of the scaffolding shall be reasonable, complete and complete, and shall ensure that the force transmission of the frame is clear and the force is uniform.
4.4.2 The connection nodes of the scaffolding rods shall have sufficient strength and rotational stiffness, and the nodes of the frame shall not be loose during the service life.
4.4.3 The spacing and step distance of the scaffolding uprights shall be determined by design.
4.4.4 Safety protection measures shall be taken on the scaffolding working layer, and shall comply with the following provisions:
① The working layer of the working scaffolding, full-floor supporting scaffolding, and attached lifting scaffolding shall be fully covered with scaffolding boards and shall meet the requirements of stability and reliability. When the distance between the edge of the working layer and the outer surface of the structure is greater than 150mm, protective measures should be taken.
② Steel scaffolding boards connected by hooks should be equipped with self-locking devices and locked with the horizontal bars of the working layer.
③ Wooden scaffolding boards, bamboo scaffolding boards, and bamboo scaffolding boards should be supported by reliable horizontal bars and should be tied firmly.
④ Guardrails and footboards should be set at the outer edge of the scaffolding working layer.
⑤ Closing measures should be taken for the bottom scaffolding boards of the working scaffolding.
⑥ A layer of horizontal protection should be set every 3 floors or at a height of no more than 10m along the construction building.
⑦ The outside of the working layer should be closed with a safety net. When a dense safety net is used for closure, the dense safety net should meet the flame retardant requirements.
⑧ The part of the scaffolding board extending beyond the horizontal horizontal bar should not be greater than 200mm.
4.4.5 The vertical poles at the bottom of the scaffolding should be equipped with longitudinal and transverse sweeping poles, and the sweeping poles should be firmly connected to the adjacent vertical poles.
4.4.6 The working scaffolding shall be equipped with wall ties according to the design calculation and construction requirements, and shall meet the following requirements:
① The wall ties shall be rigid components that can withstand pressure and tension, and shall be firmly connected to the engineering structure and the frame;
② The horizontal spacing of the wall ties shall not exceed 3 spans, the vertical spacing shall not exceed 3 steps, and the cantilever height of the frame above the wall ties shall not exceed 2 steps;
③ Wall ties shall be added at the corners of the frame and the ends of the open-type working scaffolding. The vertical spacing of the wall ties shall not be greater than the building floor height, and shall not be greater than 4m.
4.4.7 Vertical scissors braces shall be installed on the longitudinal outer facade of the working scaffolding and shall comply with the following provisions:
① The width of each scissors brace shall be 4 to 6 spans, and shall not be less than 6m or greater than 9m; the inclination angle between the scissors brace diagonal rod and the horizontal plane shall be between 45° and 60°;
② When the erection height is below 24m, a scissors brace shall be installed at both ends of the frame, corners, and in the middle every 15m, and shall be installed continuously from bottom to top; when the erection height is 24m and above, it shall be installed continuously from bottom to top on the entire outer facade;
③ Cantilever scaffolding and attached lifting scaffolding shall be installed continuously from bottom to top on the entire outer facade.
4.4.8 The bottom of the cantilever scaffolding pole shall be reliably connected to the cantilever support structure; a longitudinal sweeping rod shall be installed at the bottom of the pole, and horizontal scissors braces or horizontal diagonal braces shall be installed intermittently.
4.4.9 The attached lifting scaffolding shall comply with the following provisions:
① The vertical main frame and horizontal supporting truss shall adopt a truss or rigid frame structure, and the rods shall be connected by welding or bolts;
② Anti-tilting, anti-falling, floor stop, load, and synchronous lifting control devices shall be installed, and all kinds of devices shall be sensitive and reliable;
③ A wall support shall be set on each floor covered by the vertical main frame; each wall support shall be able to bear the full load of the vertical main frame;
④ When electric lifting equipment is used, the continuous lifting distance of the electric lifting equipment shall be greater than the height of one floor, and it shall have braking and positioning functions.
4.4.10 Reliable structural reinforcement measures shall be taken for the following parts of the working scaffolding:
① The connection between the attachment and support of the engineering structure;
② The corner of the plane layout;
③ The disconnection or opening of facilities such as tower cranes, construction elevators, and material platforms;
④ The part where the floor height is greater than the vertical height of the wall connection;
⑤ The protruding objects of the engineering structure affect the normal layout of the frame. 4.4.11 Effective hard protection measures should be taken at the outer facades and corners of the street-facing scaffolding.
4.4.12 The height-to-width ratio of the independent frame of the supporting scaffolding should not be greater than 3.0.
4.4.13 The supporting scaffolding should be equipped with vertical and horizontal scissor braces and should comply with the following provisions:
① The setting of the scissor braces should be uniform and symmetrical;
② The width of each vertical scissor brace should be 6m~9m, and the inclination angle of the scissor brace diagonal rod should be between 45° and 60°.
4.4.14 The horizontal rods of the supporting scaffolding should be continuously set along the longitudinal and transverse lengths according to the step distance and should be firmly connected to the adjacent vertical rods.
4.4.15 The length of the adjustable base and adjustable support screw inserted into the scaffolding pole should not be less than 150mm, and the extension length of the adjusting screw should be determined by calculation and should comply with the following provisions:
① When the diameter of the inserted pole steel pipe is 42mm, the extension length should not be greater than 200mm;
② When the diameter of the inserted pole steel pipe is 48.3mm and above, the extension length should not be greater than 500mm.
4.4.16 The gap between the adjustable base and adjustable support screw inserted into the scaffolding pole steel pipe should not be greater than 2.5mm.
Post time: Jan-17-2025