Open Anchor

Open Anchorage is composited with a round anchor head and wedge. We produce this kind of mono anchorage for stressing a single tendon.

Open Anchorage includes the anchorage for stressing pc wire, the wire diameter could be from 3mm to 11mm, this anchorage system is usually used in prefabrication of concrete products.

Open Anchorage includes the anchorage for underground roadway roof and surrounds reinforcement, this anchorage is for anchoring single strands of big diameter, usually, the strand diameter will be 17.8mm, 21.8mm, and 28.6mm; we produce this kind of anchorage strictly in accordance with the standard MT /T 942 which is for prestressed anchorage in the coal mine. The anchorage system has reliable anchoring performance, good load-bearing capacity, and applicability.

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ADVANTAGES

In the context of prestressed materials, an "open anchor" refers to a type of anchorage used to transfer the prestressing forces from the tendons (cables or bars) to the surrounding concrete in a prestressed structure. Anchor points are essential in this process, as they are where the tendons are held securely, ensuring the forces are effectively transferred to the concrete.

What is an Open Anchor?

The open anchor is a type of anchorage system where the anchoring components are accessible and visible after installation. This accessibility allows for inspection, maintenance, and adjustment if necessary. Open anchor systems are designed to secure the prestressing tendons at the ends of concrete members, ensuring that the applied prestress forces are effectively transferred to the concrete and maintained over the structure's lifespan.

An "open anchor" may refer to a specific configuration where the anchor is accessible or exposed during the tensioning process. This contrasts with other configurations where the anchor might be embedded or concealed in the concrete. The open design allows for easier adjustments or inspections during the tensioning process.

These anchor points are critical in ensuring that the prestressing force is properly applied and maintained over time, contributing to the structural integrity and longevity of the building or component.

● Ease of Inspection: The open design allows engineers and inspectors to easily examine the condition of the anchorage, ensuring ongoing structural safety.

● Maintenance and Adjustment: Accessibility facilitates maintenance activities, such as retensioning or replacing components if necessary.

● Detection of Issues: Any signs of corrosion, damage, or stress can be detected early, allowing for timely remedial actions.

● Flexibility in Construction: Open anchorages can accommodate adjustments during and after construction, providing flexibility in managing construction tolerances and unforeseen issues.

USE

● Bridge Construction: Used in post-tensioned girders and decks where ongoing inspection is critical due to exposure to environmental conditions.

● Building Structures: Employed in slabs, beams, and walls requiring high levels of prestress and where accessibility for maintenance is desired.

● Repair and Retrofitting: Ideal for strengthening existing structures where new prestressing needs to be applied, and monitoring is necessary.

Comparison with Closed Anchor Points

Closed Anchor Points are encapsulated systems where the anchorage components are embedded within the concrete and not accessible after installation.

Differences:

Accessibility: Open systems are accessible post-installation; closed systems are not.

Inspection: Open systems allow for routine inspection; closed systems rely on initial construction quality and protective measures.

Protection: Closed systems provide better protection against environmental factors (e.g., moisture, corrosion) as components are sealed within the concrete.

Usage: Choice between open and closed systems depends on factors like environmental exposure, maintenance plans, and structural requirements.

SPECIFICATIONS

Key Components of an Open Anchor System

1. Anchor Head/Plate:

Distributes the prestressing force from the tendon to the concrete.

Typically made of high-strength steel to withstand significant forces.

The open design allows for visual inspection and access.

2. Wedges/Grip Systems:

Used to grip and hold the tendon firmly in place.

The wedges bite into the tendon when tension is applied, preventing slippage.

Accessible for adjustments or replacements if needed.

3. Bearing Plate:

Provides a surface for the anchor head to transfer forces uniformly to the concrete.

Ensures that stresses are evenly distributed, preventing local crushing of concrete.

4. Trumpet/Cone:

A conical or cylindrical component that guides the tendon into the anchor head.

Allows for slight angular deviations and smooth force transfer.

In open systems, the trumpet may be designed to allow inspection of the tendon entering the anchorage.

5. Reinforcement/Spiral Reinforcement:

Additional reinforcement is provided around the anchorage zone to handle bursting and spalling stresses.

Ensures the concrete around the anchor can sustain the concentrated forces.