High-grade #40C Steel Mono Strand Coupler with Galvanized Corrosion Resistance for 12.7mm to 15.2mm Strand Diameter

A Mono Strand Coupler (also called a Single Strand Anchor Coupler or Intermediate Anchorage) is a precision-engineered post-tensioning accessory designed to create a continuous, high-strength connection between two individual prestressing strands. Its primary function is to extend the length of a tendon, either for long-span applications or to connect tendons at construction joints, ensuring the uninterrupted transfer of tensile forces through the concrete structure.

Unlike multi-strand anchors that handle bundles, this coupler is designed for a single PC strand, typically ranging from 12.7mm (0.5") to 15.2mm (0.6") in diameter. It is a critical component in both pre-tensioning and post-tensioning construction methods, enabling design flexibility and construction efficiency in modern concrete projects.

The coupler works on a simple yet robust mechanical principle. It consists of a central coupler body with a threaded or cylindrical interior at both ends. Each end accepts a strand-anchor assembly (comprising a threaded anchor barrel and wedges). When the two strands are inserted and tensioned, the wedges inside the anchor barrels lock onto the strands, while the barrels themselves are secured within the coupler body. This creates a rigid, end-to-end connection that matches or exceeds the strength of the strand itself, allowing full prestressing force to pass through the joint.

Mono Strand Couplers are manufactured to exacting standards from high-strength materials. The following table outlines the common specifications for standard models:

• Enables Long-Span Construction: Allows for the creation of post-tensioning tendons longer than standard manufactured or transportable lengths, which is crucial for large bridges, beams, and slabs.
• Facilitates Stage Construction: Used at construction joints where concreting is done in phases, allowing tendons from one segment to be securely connected to the next.
• Provides Repair and Strengthening Capability: Essential for tendon splicing in structural repair, retrofit, and strengthening projects where existing tendons need to be extended or reconnected.
• Maintains System Integrity: A properly installed coupler ensures the tendon maintains its full design load capacity, corrosion protection continuity, and long-term durability.
• Offers Versatility: Available for use with both bonded post-tensioning systems (grout-filled ducts) and unbonded monostrand systems (grease-coated and plastic-sheathed). Advanced models like the Zero Void® Intermediate Anchorage are designed specifically for bonded systems to ensure complete grout encapsulation without voids.

This component is vital across a wide spectrum of civil and structural engineering projects:

• Bridge Construction: Connecting tendons in long-span precast segmental bridges, box girders, and bridge deck continuity.
• Building Structures: Creating continuous tendons in transfer beams, long-span floor slabs, and at construction joints in high-rise cores.
• Infrastructure Projects: Used in containment structures, large water tanks, and heavy foundations.
• Geotechnical & Slope Stabilization: Splicing strands in long ground anchors and tiebacks for retaining walls and landslide mitigation.

Correct installation is paramount for performance and safety.

1. Preparation: Expose the strands to be connected and ensure they are clean and undamaged. Confirm the coupler components match the strand size and type.
2. Assembly: Insert the first strand into its anchor barrel and seat the wedges. Thread this assembly into one end of the coupler body. Repeat the process with the opposing strand in the other end.
3. Stressing: Use a calibrated mono-strand hydraulic jack to tension the coupled tendon to the specified force.
4. Grouting (for Bonded Systems): For systems like the GTI Zero Void®, follow specific procedures to inject grout through the coupler, ensuring the entire void space is filled for corrosion protection.
5. Pocket Grouting & Finishing: Once stressing is verified, seal the anchorage pocket with non-shrink grout for final protection.

• Certification: Ensure products come with valid material certificates and are from suppliers with ISO 9001 quality management certification.
• Compatibility: Verify that all components—coupler body, anchor barrels, and wedges—are from the same manufacturer and system.
• Third-Party Inspection: For critical projects, consider sourcing from audited suppliers and request inspection reports from agencies like SGS or BV.

The Mono Strand Coupler is more than a simple connector; it is the engineered solution that ensures the integrity and continuity of post-tensioning forces in modern concrete structures. It empowers engineers to design more ambitious spans and enables contractors to build more efficiently, without being constrained by material lengths or construction sequences.

Choosing a high-quality coupler from a reputable supplier, backed by proper design and installation expertise, is an investment in the safety, durability, and longevity of the structure.