Scaffolding design
1. You should have a clear understanding of heavy-duty scaffolding. Generally, if the floor thickness exceeds 300mm, you should consider designing according to heavy-duty scaffolding. If the scaffolding load exceeds 15KN/㎡, the design plan should be organized for expert demonstration. It is necessary to distinguish those parts where changes in the length of the steel pipe have a greater impact on the load-bearing. For the formwork support, the length between the center line of the top horizontal pole and the formwork support point should not be too long. It is generally less than 400mm. When calculating the vertical pole Generally, the top step and the bottom step bear the greatest force and should be used as the main calculation points. When the bearing capacity does not meet the group requirements, vertical poles should be added to reduce the vertical and horizontal spacing or horizontal poles should be added to reduce the step distance.
2. It is common for domestic scaffolding to have substandard materials such as steel pipes, fasteners, jacks, and bottom brackets. These are not taken into account in theoretical calculations during actual construction. It is best to adopt a certain safety factor in the design calculation process.
Scaffolding construction
The sweeping rod is missing, the vertical and horizontal junctions are not connected, the distance between the sweeping rod and the ground is too large or too small, etc.; the scaffolding board is cracked, the thickness is not enough, and the overlap does not meet the specification requirements; after the large formwork is removed, there is no protective barrier between the inner vertical pole and the wall. The net fell; the scissor braces were not continuous in the plane; the open scaffolding was not equipped with diagonal braces; the spacing between the small horizontal bars under the scaffolding board was too large; the wall-connecting parts were not rigidly connected inside and outside; the spacing between the protective railings was greater than 600mm; the fasteners were not tightly connected. Fastener slippage, etc.
Scaffolding deformation accident
1. Local deformation of the scaffolding caused by foundation settlement. Set up eight-shaped beams or scissor braces on the transverse section of the double-row frame, and set up a set of vertical poles every other row until the outer row of the deformation zone. The horoscope or scissor leg must be placed on a solid and reliable foundation.
2. If the deflection deformation of the cantilevered steel beam on which the scaffolding is based exceeds the specified value, the rear anchor point of the cantilevered steel beam should be reinforced, and the steel beam should be tightened with steel supports and U-shaped brackets to hold up against the roof. There is a gap between the embedded steel ring and the steel beam, which must be tightened with horse wedges. The steel wire ropes hanging from the outer ends of the steel beams are inspected one by one and all are tightened to ensure uniform stress.
3. If the scaffolding unloading and tensioning system is partially damaged, it must be restored immediately according to the unloading and tensioning method formulated in the original plan, and the deformed parts and rods must be corrected. To correct the outward deformation of the scaffolding, first set up a 5t inverted chain in each bay, tighten it with the structure, loosen the rigid pull connection point, and tighten the inverted chain inward at each point at the same time until the deformation is corrected, and do the rigid pull. Connect, tighten the wire rope at each unloading point to make it evenly stressed, and finally release the reverse chain.
Post time: Nov-01-2023