How to Solve the Problem of Steel Wire Slippage During Prestressed Construction?

If wire slippage is discovered during construction, you can try the corresponding methods provided in this article. The core principle for addressing wire slippage in prestressed steel wire construction is to "first assess the severity, then precisely address the situation based on the scenario, and then conduct enhanced inspection and acceptance." Specifically, this can be done in three steps: "Emergency Treatment → Classified Repair → Preventive Reinforcement."

I. Emergency Treatment, Stop Losses Immediately

1. Stop Construction, Lock Down: Upon detecting wire slippage, immediately halt tensioning and subsequent operations. Record the location, number of slippages, and prestress loss (using oil pressure gauge readings or elongation comparisons) to avoid further slippage or structural deformation caused by continued operation.

2. Temporary Fixation for Safety: If a slipped wire shows signs of loosening, temporarily secure it with a dedicated clamp to prevent further slippage. Mark the slipped area and prohibit access to personnel to prevent unbalanced component forces and potential safety hazards.

II. Repair by Category, Treating According to the Severity of Thread Slip

1. Minor Thread Slip (No more than one thread slipped per bundle, and prestress loss less than 5% of the design value)

- Re-tensioning Repair: If the thread slip is caused by insufficient tensioning or loose clips, and the anchor and wire are not damaged, re-tension the slipped bundle using properly calibrated tensioning equipment until the design prestress value is reached (monitor the stresses of adjacent bundles during re-tensioning to avoid cross-stressing).

- Clip Adjustment: If thread slip is caused by clip misalignment or wear, remove the original clip, clean any impurities from the anchor taper, replace with a new clip of the same specification, and reinstall and re-tension according to specifications.

2. Moderate Wire Slippage (2-3 wires in a single bundle, or 5%-10% prestress loss)

- Anchor Replacement + Re-Tensioning: Remove the original anchor and inspect the wire surface for damage (such as scratches or rust). If the wire is intact, replace it with a new, factory-matched anchor and clip. After reinstalling, tension the wire in stages to the design stress. If the wire is slightly damaged locally, reinforce it with special repair tape before tensioning.

- Additional Anchorage Treatment: If the risk of wire slippage persists after re-tensioning, install an additional anchor (such as a squeeze anchor) outside the original anchor. This double anchoring ensures wire stability. The additional anchor must be compatible with the original anchor, and the overall anchoring force must be verified after installation.

3. Severe Wire Slippage (>3 wires in a single bundle, or prestress loss >10%, or wire breakage)

- Cutting and Re-tensioning + Wire Replacement: If wire slippage is accompanied by wire damage or severe anchorage damage, the bundle must be cut using specialized cutting tools. The damaged wire and anchorage must be removed and replaced with new prestressing wires of the same specification (ensuring the same material and diameter as the original wire). After re-threading the bundle and installing the anchorage, the prestressing process can be repeated according to the complete tensioning process.

- Structural Reinforcement: If wire slippage results in a severe localized prestressing deficiency in the component, the structural load-bearing capacity must be verified in conjunction with the design firm. If necessary, reinforcement measures such as attaching carbon fiber sheeting or adding additional prestressing strands may be employed to ensure the component meets design requirements.

III. Root Cause Identification and Preventive Reinforcement

1. Trace the cause of wire slippage and thoroughly rectify the problem:

- If it's due to product quality (poor anchor clip fit, wire defects): Replace the anchors and wire with genuine, factory-provided, nationally standardized anchors and wires. Strictly inspect the mechanical properties and appearance before delivery.

- If it's due to construction operations (irregular tensioning, incorrect installation): Retrain construction personnel, strictly adhere to the "staged tensioning and real-time elongation monitoring" requirements, and thoroughly clean the anchors and wires before tensioning.

- If it's due to equipment issues (inaccurate tensioning equipment): Immediately recalibrate the jacks and oil pressure gauges, and replace worn auxiliary tools (such as guides and tool anchors).

- If it's due to environmental factors (corrosion, low temperatures): Implement targeted protective measures (such as applying rust inhibitors or building a heat shield) to improve the construction environment. 

2. Strengthened Inspection and Acceptance, Double Guarantee:

- After repairs are completed, re-test the prestressing value (using tensioning equipment readings, ultrasonic stress monitoring, etc.) to ensure it meets design requirements. Check that the anchors and wires are free of looseness and deformation, and that their appearance meets acceptable standards.

- During subsequent construction, increase inspection frequency (inspect the anchor condition every 10 bundles tensioned). After tensioning, allow the anchors to rest for 15-20 minutes before re-tensioning. Ensure that the anchors are promptly treated for corrosion.

As a supplier in the prestressed steel industry, we offer specialized tools for thread stripping treatment (such as re-tensioning equipment and supporting anchors). We also provide on-site technical guidance based on project specifics to help you efficiently resolve thread stripping issues. If you require a "Prestressed Steel Thread Stripping Treatment Operational Flowchart" or a repair plan tailored to your specific project scenario, we can immediately provide it for you. You can contact us directly via the phone and email listed on our website, or visit our official website for a quote.