21.8mm 2230 Mpa PC Strand

21.80mm 2230MPa low relaxation Prestressed Steel strand full analysis and application scenarios

I. Product core parameters and structural characteristics

Specification definition: Nominal diameter 21.80mm, made of 19 high-strength steel wires (usually 1+9+9 three-layer structure), cross-sectional area of ​​about 365mm², theoretical weight of about 2.86kg per meter, standard tensile strength of 2230MPa, belongs to ultra-large diameter, ultra-high strength prestressed steel.

Mechanical properties:

Single strand breaking force: ≥810kN (365mm²×2230MPa), 2.6 times that of 15.20mm steel strand (breaking force of about 312kN);

Low relaxation characteristics: 1000-hour relaxation rate ≤1.5% under 70% nominal stress, stress loss is 80% lower than that of ordinary steel strand;

Elastic modulus 195-200GPa, elongation ≥3.5%, meeting the high-strength grade requirements of GB/T 5224-2014.

II. Production process and technical highlights

Structural design:

Adopting 19-wire multi-layer twisting process, the diameter of the center wire is slightly larger than the outer wire (such as the diameter of the center wire is 3.0mm, and the outer wire is 2.8mm), and the twist pitch is 10-14 times the diameter, which improves the structural density and torsion resistance.

Surface treatment:

Generally, it is smooth or zinc-aluminum alloy coating (zinc layer weight ≥ 400g/m²). For special scenarios, epoxy coating (thickness ≥ 0.5mm) or HDPE sheath can be customized to adapt to strong corrosive environments such as oceans and chemical industries.

3. Typical application fields and scenarios

Application fields Specific engineering scenarios Technical advantages

Ultra-large span bridges Main cables of suspension bridges (such as cross-strait bridges), anchor sections of main towers of cable-stayed bridges, and main beam prestressed systems of dual-use bridges for highways and railways Single-core bearing capacity covers 800-1000kN, reducing the number of steel cables and simplifying anchor design, suitable for bridges with a span of more than 1000 meters.

Heavy buildings and foundations Prestressed tensioning of giant columns of super-high-rise steel structures, circumferential reinforcement of nuclear power plant containment, and deep foundation pit support (depth > 50m) Large diameter sections reduce the number of tensioning times, and low relaxation characteristics ensure stress stability within a service life of more than 50 years, reducing the risk of nuclear containment leakage.

Marine engineering Offshore wind power monopile foundation tensioning (pile diameter ≥ 5m), cross-sea tunnel lining prestressing, LNG tank annular anchoring Corrosion-resistant coating with high stress stability, resist seawater chloride ion erosion, and reduce fatigue damage under wave load.

Water conservancy and energy engineering High dam body anchoring (dam height > 200m), pumped storage power station pressure pipeline prestressing, shale gas well wall support Large diameter steel strands can withstand surrounding rock pressure exceeding 200MPa, and low relaxation performance avoids stress attenuation under long-term water pressure.

4. Comparison with small and medium diameter steel strands

Dimension 21.80mm 2230MPa steel strand 15.20mm 1860MPa steel strand

Single strand bearing capacity 810kN (about 82 tons) 260kN (about 26 tons)

Applicable span >1000m bridge <500m bridge

Anchor specifications Matching large-aperture anchors (such as YM22-19) Conventional XM15-7 anchors

Construction efficiency Single-beam tensioning covers a larger cross-section and reduces the density of reinforcement. Dense reinforcement is required, and the number of tensioning times is high

Economical Unit price is 30%-40% higher, but the total amount is reduced by more than 50% The initial cost is low, and the cost of consumables in large-span scenarios is higher

5. Key points of construction

Tensioning control:

Tensioning stress should be taken as standard strength 60%-70% (1338-1561MPa), hydraulic synchronous tensioning equipment (single cylinder tension ≥1000kN), elongation deviation controlled within ±5%.

Anchors need to undergo fatigue tests (no slip under 2 million cycles of load), concrete strength in the anchoring area ≥C50, to avoid local pressure damage.

Quality inspection:

On-site acceptance requires re-inspection of tensile strength, relaxation rate, and torsion performance, and 2 roots are extracted from each batch (≤30t) for breaking tests;

After construction, fiber optic sensing technology is used to monitor the stress distribution of the entire section, and regular inspection of the sealing of the anchor head (to prevent rainwater from penetrating and corroding).21.8mm 2230 Mpa PC Strand

Chunpeng Group is a leading and professional manufacturer of prestressed concrete (PC) steel materials, with over 30 years of industry experience.

We are committed to delivering high-quality products and innovative solutions for infrastructure and construction projects worldwide.

Our Core Products are pc steel strand (Ultra High Tensile Strength PC Strand, Normal Tensile Strength PC Strand), Unbonded PC Strand, Galvanized PC Steel Strand, Weather-Resistant & Anti-Corrosion PC Strand, and PC Steel Wire. 

In addition to our PC strand products, we also supply Prestressed Anchorage Systems and Photovoltaic Mounting Systems.