Detailed interpretation of the structural requirements of each part of the scaffolding 2

Requirements for the construction of transverse diagonal braces

The setting of transverse diagonal braces for double-row scaffolding shall comply with the following provisions: 1. The transverse diagonal braces shall be arranged continuously in a zigzag shape from the bottom to the top in the same interval. 2. For closed double-row scaffolding with a height of less than 24m, transverse diagonal braces may not be set. For closed scaffolding with a height of more than 24m, transverse diagonal braces shall be set every 6 spans in the middle, except for the corners. 3. Transverse diagonal braces must be set at both ends of the open double-row scaffolding. The two ends of the open scaffolding are weak links. Setting transverse diagonal braces at both ends and strengthening the connection with the main structure can improve the overall rigidity of this type of scaffolding.

Requirements for the construction of ramps

Ramps, or horse paths, are passages for people to go up and down. All kinds of people must walk on specially set pedestrian passages (ramps) when going up and down scaffolding, and are not allowed to climb scaffolding. The passage can be attached to the scaffolding or set up independently near the building. 1. The load on the poles at the ramp is often the largest because there are scaffolding boards and footboards at each level. Therefore, the stability of the poles at the ramp should be verified. If it is insufficient, the method of adding steel pipe poles or local unloading measures can be adopted. 2. The type of ramp for pedestrians and material transportation should be determined according to the following requirements (1) For scaffolding with a height of no more than 6m, a straight ramp should be adopted. (2) For scaffolding with a height of more than 6m, a zigzag ramp should be adopted.

3. Structural requirements for ramps: (1) The ramp should be attached to the external scaffolding or building; (2) Scissor braces must be installed on both sides, ends and the periphery of the platform of the ramp. For ramps with a width greater than 2 meters, a zigzag lateral support should be installed under the small crossbar under the scaffolding board; (3) The width of the material transport ramp should not be less than 1.5m, and the slope should be 1:6 (height: length); the width of the pedestrian ramp should not be less than 1m, and the slope should be 1:3; (4) Platforms should be set at the corners. Its width should not be less than the ramp width; (5) Railings and footboards should be installed on both sides of the ramp and the periphery of the platform. The height of the railing should be 1.2m, and the height of the footboard should not be less than 180mm; (6) Wall ties should be installed on both sides of the material transport ramp, the periphery of the platform and the ends according to the provisions of the wall ties. Horizontal diagonal bars, scissor braces and transverse diagonal braces should be added every two steps. 4. The structure of the ramp scaffolding board should comply with the following regulations: (1) When the scaffolding board is laid horizontally, a longitudinal support bar should be added under the horizontal bar, and the spacing between the longitudinal support bars should not be greater than 500mm; (2) When the scaffolding board is laid in parallel, the joints should be overlapped; the lower board head should press the upper board head, and the convex edges of the board head should be filled with triangular wood; (3) On the scaffolding boards of pedestrian ramps and material transport ramps, a non-slip wooden strip should be installed every 250-300mm, and the thickness of the wooden strip should be 20-30mm.

Structural requirements for full-floor scaffolding

(1) Full-floor scaffolding should be equipped with continuous vertical scissors braces from bottom to top on the outer sides of the frame and every 6m to 8m in the longitudinal and transverse directions inside. When the frame is erected at a height of less than 8m, continuous horizontal scissors braces should be installed at the top of the frame; when the frame is erected at a height of 8m or more, continuous horizontal scissors braces should be installed at the bottom and top of the frame and at vertical intervals not exceeding 8m. Horizontal scissors braces should be installed at the intersection of the vertical scissors brace diagonal bars. The width of the scissors braces should be 6m to 8m.

(2) The height-to-width ratio of full-floor scaffolding should not be greater than 3. When the height-to-width ratio is greater than 2, wall ties should be installed on the outer sides of the frame and inside at horizontal intervals of 6m to 9m and vertical intervals of 4m to 6m to connect with the building structure. When wall ties cannot be installed, measures such as setting up wire rope tensioning and fixing should be taken.

(3) When the full-floor scaffolding is partially subjected to concentrated loads, it should be calculated according to the actual load and locally reinforced.

(4) A ladder should be provided for the full-floor scaffolding, and the spacing between the ladder steps should not be greater than 300mm.

Structural requirements for full-floor support frames

(1) The length of the full-floor support frame from the center line of the top horizontal bar to the support point should not exceed 0.5m. The height of the full-floor support frame should not exceed 30m.

The extension length of the adjustable support screw should not exceed 300mm, and the length inserted into the vertical bar should not be less than 150mm.

(2) The full-floor support frame should be equipped with scissor braces according to the type of frame, and should comply with the following regulations: ① Ordinary type: Continuous vertical scissor braces should be provided from bottom to top every 5m to 8m on the outer periphery of the frame and in the longitudinal and transverse directions inside, and the width of the scissor braces should be 5m to 8m.

Continuous horizontal scissor braces should be provided at the intersection plane of the top of the vertical scissor braces. When the support height exceeds 8m, or the total construction load is greater than 15kN/㎡, or the concentrated line load is greater than 20kN/m, the sweeping rod setting layer should be equipped with horizontal scissors braces. The distance from the horizontal scissors brace to the bottom plane of the frame and the spacing between the horizontal scissors braces should not exceed 8m. Rigid connections should be made with the structural columns around and in the middle of the bracket, with a horizontal spacing of 6-9m and a vertical spacing of 2-3m.

②Reinforced type: 1) When the vertical and horizontal spacing of the vertical poles is 0.9m×0.9m~1.2m×1.2m, continuous vertical scissors braces should be set from bottom to top every 4 spans (not more than 5m) on the outer periphery of the frame and the internal longitudinal and transverse directions. The width of the scissors brace should be 4 spans. 2) When the vertical and horizontal spacing of the vertical poles is 0.6 m×0.6m～0.9 m×0.9m, continuous vertical scissors braces should be set from bottom to top every 5 spans (not less than 3m) on the outer periphery and the inner longitudinal and transverse sides of the frame, and the width of the scissors braces should be 5 spans. 3) When the vertical and horizontal spacing of the vertical poles is 0.4 m×0.4m～0.6 m×0.6m, continuous vertical scissors braces should be set from bottom to top every 3m～3.2m on the outer periphery and the inner longitudinal and transverse sides of the frame, and the width of the scissors braces should be 3m～3.2m. 4) Horizontal scissors braces should be set at the intersection plane of the top of the vertical scissors braces. The distance from the horizontal scissors brace to the bottom plane of the frame and the spacing of the horizontal scissors braces should not exceed 6m, and the width of the scissors braces should be 3m～5m.

Bowl-hook support frame construction requirements

1. The template support frame should select the vertical pole spacing and step distance according to the load it bears. The bottom longitudinal and transverse horizontal bars are used as sweeping bars, and the height from the ground should be less than or equal to 350mm. The bottom of the vertical pole should be equipped with an adjustable base or a fixed base; the length of the upper end of the vertical pole including the adjustable screw extending from the top horizontal pole shall not be greater than 0.7m. 2. Requirements for setting diagonal bars of formwork support frame: ① When the distance between vertical bars is greater than 1.5m, special diagonal bars with full height should be set at the corners, and full height eight-shaped diagonal bars or scissor braces should be set in each row and column in the middle; ② When the distance between vertical bars is less than or equal to 1.5m, vertical scissor braces should be set continuously from bottom to top around the formwork support frame; vertical scissor braces should be set continuously from bottom to top in the middle longitudinal and transverse directions, and the spacing should be less than or equal to 4.5m; ③ The angle between the diagonal bars of the scissor braces and the ground should be between 45° and 60°, and the diagonal bars should be buckled with the vertical bars at each step 3. When the height of the formwork support frame is greater than 4.8m, horizontal scissor braces must be set at the top and bottom, and the spacing between the horizontal scissor braces in the middle should be less than or equal to 4.8m.

Requirements for the structure of the disc-type support frame

1. The exposed length of the adjustable screw rod of the adjustable base of the formwork support should not be greater than 300mm, and the height of the bottom horizontal rod as the sweeping rod from the ground should not be greater than 550mm2. The cantilever length of the adjustable bracket of the formwork support extending from the top horizontal rod or double-slot steel support beam is strictly prohibited to exceed 650mm, and the exposed length of the screw rod is strictly prohibited to exceed 400mm, and the length of the adjustable bracket inserted into the vertical rod or double-slot steel support beam shall not be less than 150mm. 3. The pitch of the horizontal rod at the top of the tall formwork support should be reduced by one disc-type pitch compared with the standard pitch.

4. Requirements for the setting of diagonal rods or scissor braces of the formwork support: ① For full-floor formwork supports with a height of ≤8m, the pitch should be ≤1.5m. Vertical diagonal rods should be set on each layer of the first span of the external facade around the support frame, and vertical diagonal rods should be set on the bottom and top of the frame as a whole. Vertical diagonal rods should be set vertically and horizontally from bottom to top every 5 spans in the internal area of the frame, or scissor braces should be set with fastener steel pipes. When the height of the full-floor formwork support does not exceed 4 steps, the top horizontal diagonal bar may not be set; when the height of the frame exceeds 4 steps, the top horizontal diagonal bar or the horizontal scissor brace of the fastener steel pipe should be set.

② When erecting a full-floor formwork support with a height of more than 8m, the vertical diagonal bars should be fully set, and the step should not be greater than 1.5m. Horizontal layer diagonal bars or fastener steel pipe scissor braces should be set every 4 to 6 standard steps along the height. When there are structures around, it is advisable to form a reliable tie with the surrounding structure.

③ When the formwork support is erected into an independent tower-shaped support without lateral ties (large height-to-width ratio), vertical diagonal bars should be set at each step on each side of the frame. When there is a requirement for anti-torsion, horizontal layer diagonal bars or horizontal scissor braces of steel pipes should be added on the top layer and every 3-4 steps.