What Are the Installation Requirements for Pre-Embedded Countersunk Bolts?

The installation of pre-embedded sockets must meet four major requirements: "precise positioning, firm fixing, reliable corrosion protection, and qualified load-bearing capacity", primarily following the Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Buildings (JGJ/T423-2018). Through laser positioning and standardized construction, Qinglong has achieved a 99.8% pass rate for socket installation, and projects such as the Shenzhen Pingshan High-tech Zone Comprehensive Service Center have no hidden risks of socket loosening.

1. Position and Dimension Requirements: Precise Positioning Without Deviation

Positioning accuracy is the core prerequisite for installation. Position deviation control: socket center position deviation ≤±2mm, elevation deviation ≤±3mm, horizontal deviation ≤1mm/m. Qinglong uses laser positioning instruments plus BIM modeling assistance to reduce positioning deviation to within ±1mm. Spacing requirements: socket spacing is adjusted according to GRC component weight; light components (≤50kg) require spacing ≤600mm, heavy components (>200kg) require spacing ≤400mm, and sockets must be added at corner positions. Qinglong's socket spacing for heavy components is ≤350mm, ensuring uniform load distribution. Edge distance requirements: sockets must be ≥50mm from the GRC component edge to avoid edge stress concentration that causes cracking. Qinglong uniformly sets the edge distance at 60mm, balancing safety and installation space.

2. Fixing Method and Load-Bearing Requirements: Firm, Reliable and Up to Standard

The fixing method and load-bearing capacity directly affect service safety. Fixing method: pre-embedded sockets use dual fixing of "formwork fixing + rebar welding" to avoid displacement during pouring. Qinglong uses special clamps for formwork fixing and double-sided welding (weld seam length ≥50mm), achieving firm fixing without loosening. Load-bearing capacity: a single socket has pull-out resistance ≥3kN and shear resistance ≥2kN; sockets for heavy components have pull-out resistance ≥5kN. Qinglong sockets are made of stainless steel 304/316, and third-party testing shows a 100% compliance rate for pull-out resistance. Compatibility requirements: socket specifications must match GRC component thickness, with socket length ≥ component thickness + 20mm to ensure effective anchoring. Qinglong sockets are 25mm longer than the component thickness for better anchoring.

3. Anti-Corrosion Treatment and Construction Quality Control: Long-Term Stability Assurance

Anti-corrosion and process control extend socket service life. Anti-corrosion treatment: socket surfaces are coated with anti-rust paint (epoxy zinc-rich primer + topcoat), exposed parts are wrapped with anti-corrosion gaskets (butyl rubber), and coastal areas use stainless steel 316 sockets. Qinglong's anti-corrosion coating thickness is ≥150μm, with no corrosion after ≥500 hours of salt spray testing. Construction process control: before pouring GRC, oil and rust on socket surfaces are cleaned, and direct impact on sockets is avoided during pouring; Qinglong uses guide chutes during pouring and vibrates away from socket areas. Acceptance testing: after installation, a pull-out tester is used to spot-check socket pull-out resistance (3 per 100 sockets), with immediate rectification of any failures; Qinglong's spot-check pass rate reaches 99.8%. Project case: the installation of pre-embedded sockets for GRC components at Nanning Wuxiang China Resources MixC One strictly followed the above requirements, with no loosening or corrosion after years of use and stable load-bearing capacity.