15.24mm Unbonded Prestressed Steel Strand – High-Strength, Corrosion-Resistant Solution for Modern Infrastructure
Engineers and construction professionals worldwide rely on 15.24mm unbonded prestressed steel strands to enhance structural performance in demanding environments. This advanced material combines high tensile strength with exceptional durability, making it ideal for applications where speed, reliability, and long-term resilience are critical. With a nominal diameter of 15.24mm (0.6 inches), a cross-sectional area of approximately 140mm², and a tensile strength grade of 1860MPa, this strand delivers optimal load-bearing capacity while maintaining flexibility during installation. Manufactured by Chunpeng Group—a trusted global supplier with over three decades of expertise in prestressed concrete solutions—this product meets international standards for low relaxation, elastic modulus stability, and corrosion resistance.
Key features include a non-bonding design that allows free movement between the steel core and surrounding concrete, eliminating stress concentration issues common in traditional bonded systems. The outer sheath is made from high-density polyethylene (HDPE), offering excellent protection against moisture, chemicals, and environmental degradation. A specialized grease filling ensures internal lubrication and further enhances corrosion resistance, extending service life even in aggressive conditions such as coastal zones or industrial facilities. Additionally, its low relaxation behavior—less than 2.5% after 1000 hours at 70% of ultimate tensile force—ensures consistent stress retention over time, crucial for long-span structures and bridge rehabilitation projects.
The 15.24mm unbonded steel strand excels in both precast and cast-in-place construction scenarios. Its streamlined installation process eliminates the need for grouting or embedded ducts, reducing labor costs and accelerating project timelines. Unlike conventional bonded tendons, which require complex post-tensioning procedures, these strands can be tensioned directly after concrete placement, enabling efficient use in complex geometries like cantilever balconies, large roof slabs, and transition layers. The system’s inherent flexibility also supports innovative techniques such as external reinforcement of aging bridges and circumferential prestressing in liquid containment tanks, where minimizing cracking under hydrostatic pressure is essential.
Common applications span across commercial, civil, and infrastructure sectors including: high-rise building façades, airport terminals, sports arenas, highway bridges, water reservoirs, tunnel linings, and modular housing systems. Whether used in new builds or retrofitting existing structures, this strand provides superior mechanical efficiency, reduced maintenance needs, and improved safety margins. For engineers seeking cost-effective alternatives to bonded systems without compromising quality, this solution offers a compelling balance of performance, ease of handling, and sustainability.
Users consistently highlight its value in fast-track construction schedules, particularly in regions with limited access to skilled labor or challenging weather conditions. Many report significant reductions in formwork requirements and fewer delays due to simplified anchoring and tensioning procedures. The robust HDPE coating has proven effective in humid climates, protecting against premature degradation often seen in uncoated steel elements. However, users note that proper anchor selection and fireproofing measures—such as thermal insulation around the sheath—are necessary when working in high-temperature environments, as HDPE begins to soften above 130°C.
Why choose unbonded over bonded prestressed steel? While bonded systems distribute stress uniformly through cement grout, they introduce complexity in duct installation and grouting quality control. In contrast, unbonded strands offer precise force transmission via end anchors alone, simplifying quality assurance and inspection. They are especially suited for prefabricated components, where factory-controlled tensioning improves consistency and reduces on-site variability. Although friction losses must still be considered during design, modern calculation methods ensure accurate elongation values and reliable performance outcomes.
In summary, the 15.24mm unbonded prestressed steel strand stands out as a versatile, durable, and economically viable choice for contemporary engineering challenges. From architectural innovation to infrastructure resilience, it empowers builders to achieve stronger, lighter, and more sustainable designs—without sacrificing safety or longevity.
Contact Now
