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Anchor Nuts: Reliable and Durable Fastening Solutions for Construction

Anchor nuts are essential one‐sided fasteners in concrete formwork, providing secure, blindside connections when tie rods cannot pass entirely through a structure. At Avanza Steel, our anchor nuts pair with M20 and M22 tie rods, offering tool‐free installation on the pour side and robust load capacity—ensuring formwork integrity under pressures up to 60 kN/m².

What Is a Scaffolding Anchor Nut?


Unlike a standard wing nut, which engages a protruding rod outside the formwork, an anchor nut locks onto the far side of a drilled or cast‐in hole, clamping the formwork panel or shuttering plate from within the concrete mass. This allows:
 

  • Blindside Fixing
    Secure anchorage where through‐rods aren’t possible (e.g., retaining walls, tanks).

  • Tool‐Free Installation
    Ergonomic wings permit ratchet‐free tightening, even with gloved hands.

  • Damage Prevention
    Eliminates protruding hardware on the finished concrete face.

    Key Benefits:
     

  • High Load Capacity
    Rated for hydrostatic pressures up to 60 kN/m², matching our tie-rod system.

  • Ergonomic Design
    Oversized wings (65 mm for M20, 75 mm for M22) enable swift hand-tightening without tools.

  • Corrosion Resistance
    Hot-dip galvanization (≥ 85 µm zinc) protects threads and wings in alkaline, abrasive environments.

  • Reusability
    Precision-machined Grade 8.8 threads withstand over 200 cycles of assembly/disassembly.

Technical Specifications

Attribute
Specification (16 mm)
Thread Size
M16 × 2.0 mm ISO metric
Material Grade
High-tensile steel, Grade 8.8
Finish
Hot-dip galvanized (85 µm zinc)
Wing Span
55 mm overall width
Washer Compatibility
Ø 60 mm flat washer, chamfered edge
Working Load
Up to 60 kN/m² concrete pressure
Reusability
> 200 tightening cycles
Compliance
IS 1367; BS 1139; EN 10204 3.1

Components & Variants
 

  • Standard Tie Rods

    1. TR-20: M20 × 2.00 m; weight ~6.5 kg

    2. TR-25: M22 × 2.50 m; weight ~8.0 kg
       

  • Wing Nuts

    1. Ergonomic “butterfly” grip for hand-tightening; large wings for gloved hands.

    2. Zinc-plated steel with hardened internal thread insert.
       

  • Washers

    1. Ø 75 mm flat washers disperse load over shuttering plates or plywood surfaces.

    2. Chamfered edges prevent media tear of formwork faces.
       

  • Spacer Sleeves (Optional)

    1. PVC or steel sleeves for precise form thickness control (recommended for architectural surfaces).

Applications & Use Cases
 

  • Wall & Column Formwork

    Tie rods at 0.75 m vertical centres secure vertical panels, maintaining flush joints and preventing seepage.

  • Beam & Lintel Casting

    Horizontal orientation of shorter TR-15 rods holds beam shutters against bespoke waler configurations.

  • High-Pressure Pours

    In deep cores (up to 4 m), M22 rods paired with double-wing nuts handle thrusts exceeding 50 kN/m².

  • Architectural Concrete

    Spacer sleeves and precision serrated washers enable exact panel offsets, critical for reveal and soffit features.

Installation & Best Practices
 

  • Layout Planning

    1. Mark rod positions on both form faces, aligning with waler centres.

    2. Ensure rods pass cleanly through drilled panel holes.
       

  • Rod Insertion

    1. Slide rod through first panel, install spacer sleeve (if used), then pass through second panel.

    2. Engage washer and hand-tighten wing nut until panels are snug.
       

  • Adjusting Tension

    1. Use wing nut to adjust panel compression; watch for even gaps between rods and waler faces across the entire form.
       

  • Stripping

    1. After concrete reaches 70 % design strength, back off wing nuts and withdraw rods carefully to avoid concrete spalling.

Maintenance & Lifecycle
 

  • Pre-Use Check
    Inspect threads for wear or corrosion; ensure wing nuts spin freely without binding.

  • Post-Use Care
    Remove excess concrete with a soft brush; rinse rods and nuts, then dry thoroughly.

  • Storage
    Hang rods vertically in a dry, ventilated area to prevent bending and moisture buildup.

  • Lifecycle Tracking
    Maintain usage logs—replace any rod showing > 10 % thread diameter reduction or significant surface corrosion.

Ensure flawless formwork performance with Avanza Steel’s precision tie rods:


👉 Download the full Product Brochure for detailed part codes, dimensional drawings, and load charts.
 

👉 Contact our team at avanzasteel@gmail.com or +91 33 4000 7575 to request a site-specific quote, arrange a factory tour, or schedule an on-site technical consultation.

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