What Are the Consequences of Substandard Relaxation Rate in Prestressed Steel Wire?

In construction engineering, relaxation rate is a core performance indicator of prestressed steel wire. The acceptable standard for conventional grade products is a relaxation rate ≤2.5% (≤1.5% for premium grade). If the relaxation rate fails to meet the standard, the core hazard is the long-term loss of prestress, directly leading to the deterioration of component performance and an escalation of engineering safety risks. If not detected in time, it will create irreparable safety hazards for the project. As a source supplier with many years of experience in the prestressed industry, we will explain the consequences of substandard relaxation rate based on actual engineering scenarios and provide avoidance recommendations:

I. Consequences in Different Engineering Scenarios

1. Bridge Engineering (Beams, Supports): Continuous loss of prestress in the beams leads to persistent deflection and web cracking. Rainwater infiltration accelerates steel corrosion, reducing the beam's load-bearing capacity and making it unable to withstand high-frequency vehicle loads, potentially causing bridge deck collapse. Prestress failure in supports results in uneven stress distribution on the bridge, causing overall structural displacement.

2. Precast Components (Sleepers, Poles): Excessive relaxation in railway sleepers leads to prestress loss, making it difficult to maintain track smoothness. This easily results in gauge deviations and sleeper cracking, significantly increasing the risk of train derailment. Concrete poles develop longitudinal cracks due to insufficient prestress, weakening their wind and earthquake resistance and increasing the risk of breakage.

3. Building and Municipal Engineering (Floor Slabs, Pipeline Supports): Prestressed floor slabs in buildings may develop through cracks prematurely, affecting their waterproofing performance (e.g., leaks in bathrooms and roofs), and may experience subsidence and deformation over long-term use. In municipal pipeline networks, failure of prestressing can prevent the stable support of the pipeline weight, potentially leading to pipe detachment, breakage, and secondary disasters such as leaks and gas leaks.

4. Slope and Tunnel Support: Loosening of prestressed steel wires in support structures can reduce anchorage strength, making slopes prone to landslides and soil loosening. Insufficient prestressing in tunnel linings can cause cracks, potentially leading to spalling and collapse, seriously threatening construction and operational safety.

II. Avoidance Recommendations

1. Source Control: Strictly Review Supplier and Product Qualifications: Prioritize manufacturers with industry qualifications and excellent reputations, requiring them to provide test reports or certifications, clearly indicating the relaxation rate index, and resolutely rejecting products without test reports or with vague indicators. We have been deeply involved in the prestressed product field for many years, accumulating rich industry experience and stable cooperative customers. Our product quality has withstood the test of the market and we are trustworthy.

2. Process Verification: Mandatory Third-Party Sampling and Testing: For critical projects or bulk purchases, samples (≥3 pieces per batch) are taken according to standards such as GB/T 5223 and sent to a third-party laboratory for testing. The testing conditions (20℃, initial stress 70% tensile strength, 1000 hours) and results are carefully verified. Any unqualified products are returned. Our products support third-party inspection throughout the entire process; any questions can be submitted for verification at any time.

3. On-Site Verification: Precise Matching and One-Stop Supply: Upon arrival, product markings must be checked. Low-relaxation steel wire must be marked with "LR" and have no defects such as bending or rust. Simultaneously, it must be confirmed that the anchorage, tensioning equipment, and steel wire model are compatible to avoid improper construction indirectly affecting relaxation performance. We can provide a complete set of supporting facilities such as anchorages, oil pumps, and jacks, achieving one-stop supply and facilitating efficient project progress.

4. Post-construction Monitoring: Tracking and maintenance, comprehensive specification adaptation: During the operation of important projects such as bridges and tunnels, it is necessary to regularly inspect the deformation and cracks of components. If any abnormalities are found, timely reinforcement measures should be taken to prevent further damage. We stock a wide variety of prestressed products, offering a complete range of options. If you cannot find suitable products through other suppliers, please contact us, we have customized adaptation solutions for your reference.

Summary

As a source supplier with many years of production experience and service accumulation, we have won the long-term trust and support of numerous customers with our stable product quality, one-stop supporting services, and comprehensive after-sales guarantee. If you have any questions or purchasing needs related to prestressed products, please contact us via our website phone number, email, or directly click on customer service to chat or leave a message. We look forward to cooperating with you to achieve a win-win situation!