How to Match the Sizes of Three-Stage Waterstop Screws for Different Wall Thicknesses?

In construction projects,the size matching of three-section waterstop screws must be precisely designed according to the wall thickness to ensure the stability of formwork reinforcement and waterproof performance.The following are the size matching principles for inner rods,outer rods and connecting cones corresponding to different wall thicknesses:

For walls with thickness of 200-300mm,the length of the inner rod is usually the wall thickness plus 50-60mm,i.e.,250-360mm.This length should cover the cross-section of the wall and reserve space for welding the waterstop sheet.The diameter of the waterstop sheet is generally 70-80mm,and the thickness is≥3mm.The length of the outer rod needs to match the formwork thickness and support system,usually 200-250mm,with the threaded section length≥100mm to ensure sufficient engagement with the connecting cone.The connecting cone has a diameter of 30-35mm and a height of 40-45mm.The internal thread specification is consistent with that of the inner and outer rods(usually M12-M14),and the diameter of the large end of the cone should be slightly larger than the reserved hole of the formwork to prevent grout leakage.

When the wall thickness is 300-500mm,the length of the inner rod should be adjusted to 350-560mm,and the diameter of the waterstop sheet can be increased to 80-100mm to enhance the impermeable cross-section.The length of the outer rod needs to be extended to 250-300mm according to the requirements of large-scale formwork systems,and the thread precision is upgraded to grade 6g to ensure long-term stress stability.The connecting cone adopts a reinforced type with a diameter of 35-40mm and a height of 50-55mm.The cone material is upgraded to high-strength nylon or cast iron to improve impact resistance,and a waterstop ring should be added at the connection between the cone and the inner rod.

For extra-thick walls over 500mm,the inner rod needs to adopt a double nut fixing design,with a length of wall thickness plus 80-100mm.The material is Q355B grade steel with a yield strength of≥345MPa.The length of the outer rod is≥300mm,equipped with anti-slip nuts and gaskets,and the length of the threaded section is≥150mm.The connecting cone is made of cast iron with a diameter of 40-50mm,built-in reinforcing ribs,and a height of 60-70mm.It should form a double waterproof barrier with the waterstop sheet of the inner rod.A sealing rubber ring should be installed at the contact part between the cone and the formwork to further improve the anti-seepage effect.