Safety Protection for Formwork Support Systems: Key Points for Standardizing “Steel Pipe and Coupler-Type Scaffolding”

                                                                        I. Basis for Compilation:
1. Technical Specifications for Safety of Construction Formwork JGJ 162-2008
2. Technical Safety Standards for Socket-Type Disk-Coupler Steel Pipe Scaffolding in Construction JGJ/T 231-2021
3. Regulations on Safety Management of Sub-projects and Sub-items with Higher Risks Order No. 37 of the Ministry of Housing and Urban-Rural Development
4. Steel Pipe Scaffolding Couplers"GB 15831
5. Socket-Type Disk-Coupler Steel Pipe Scaffolding ComponentsJG/T 503.

 

                                                     II. Steel Pipe Coupler-Type Scaffolding:
(I) Foundation Construction:

1. Foundation Treatment Requirements:
① The subgrade must be firm and level, with bearing capacity meeting design requirements;
② A drainage slope and drainage ditches must be provided; water accumulation is strictly prohibited;
③ For scaffolding exceeding 8 m in height, a concrete base course must be poured;
④ Scaffolding may only be erected after the foundation has passed inspection

2. Installation of Base Plates and Bases:
① Base plate requirements: Length of at least two spans, width ≥ 150 mm, thickness ≥ 50 mm;
② Base requirements: Consists of a 150 × 150 × 6 mm steel plate welded to a steel pipe sleeve.

③ Installation Requirements: The load must be supported at the center of the shim; the base must fit snugly against the shim, with no parts left unsupported.

 

 

3. Special Foundation Treatment:
① When the bottoms of the columns are not at the same elevation, the sweep beam at the higher elevation shall extend toward the lower elevation by ≥2 bays.
② The elevation difference shall be ≤1 m, and the distance from the column to the upper edge of the slope shall be ≥0.5 m.
③ When supporting floor slabs, the lower floor slab shall have sufficient load-bearing capacity to support the load from the upper floor.

 

(2) Horizontal and Vertical Members:
1. Installation of sweep bars (mandatory provisions):
① Height: ≤ 200 mm above ground level
② Installation sequence: longitudinal members first, followed by transverse members
③ Requirements: to be installed continuously in both longitudinal and transverse directions, with bracing extending in both directions.

2. Requirements for the installation of horizontal members:
① Horizontal members in both longitudinal and transverse directions must be continuous in both directions, spanning no fewer than three bays
② Spacing ≤ 1.8 m (for high-rise formwork); comply with design requirements
③ Joints must be staggered by ≥ 500 mm and located no closer than one-third of the longitudinal spacing from the main node
④ Lap length ≥ 1 m, secured with three rotating couplers.

3. Requirements for the installation of vertical members:
① Extension method: Lap joints are strictly prohibited; butt joints must be used.
② Joint offset: Butt joints of adjacent vertical members must not be aligned; they must be offset by ≥500 mm.
③ Joint position: The distance from the main node must be ≤ one-third of the spacing.
④ Multi-storey shoring: The support points of upper and lower storeys must be on the same vertical line.
⑤ Prohibition of mixed use: Vertical members of different specifications must not be used together.

4. Installation of adjustable supports (mandatory provisions):
① The threaded rod must protrude no more than 200 mm from the top of the steel tube.
② The clearance between the outer diameter of the threaded rod and the inner diameter of the steel tube must not exceed 3 mm.
③ The gap between the U-shaped support and the purlin must be wedged tight.
④ Ensure that the upper and lower sections are coaxial during installation.

 

 

(3) Bracing Arrangement:
1. Vertical bracing:
① Outer perimeter: Install continuous vertical bracing from bottom to top
② Central area: Install continuous vertical bracing at 10-metre intervals in both the longitudinal and transverse directions
③ Width: 4–6 metres
④ Angle: 45°–60°
⑤ Lap Joint: Lap length ≥ 500 mm, secured with two rotating couplers.

2. Horizontal Bracing:
① Installation positions: At the top of the bracing and at the toe boards
② Storey height 8–20 m: Add one horizontal brace between the two horizontal braces at the topmost bay
③ Storey height > 20 m: Add one horizontal brace between the horizontal braces at each of the top two bays
④ Upright spacing ≤ 1.2 m: Must be installed at the top and bottom; intermediate spacing ≤ 4.8 m.

 

 

 

(4) Perimeter Tie-ins and Edge Protection:
1. Requirements for column-hugging tie-ins:
① Trigger conditions: Scaffold height > 5 m
② Horizontal spacing: 6–9 m
③ Vertical spacing: 2–3 m
④ Tie-in method: Rigid connection to the building structure using a column-hugging method
⑤ Function: To enhance overall stability and resist lateral deformation.
2. Requirements for edge protection:
① Access Measures: Where the scaffold height exceeds 2 m, access measures for workers must be provided
② Scaffold Planks: The working surface must be fully covered, with a distance from the wall of ≤150 mm; no overhanging planks are permitted
③ Safety Nets: 5 m ≤ H < 10 m: one horizontal safety net must be installed at the intermediate level; H ≥ 10 m: one horizontal safety net must be installed at intervals of 6 m; these must be installed simultaneously with the erection of the scaffold.
(V) Acceptance and Inspection:
1. Inspection Milestones:

① Upon completion of the foundations and prior to the erection of the scaffolding
② Once the scaffolding has reached the designed height
③ Following strong winds of force 6 or heavy rain
④ In cold regions, after the ground has thawed
⑤ After the scaffolding has been out of use for more than one month.

2. Inspection Personnel:
① The technical manager of the main contractor or an authorised technical specialist
② The technical manager of the subcontractor
③ The project manager and the project technical manager
④ The personnel responsible for drawing up the specialised plan
⑤ Full-time occupational health and safety management personnel