1x7 Special Purpose Pre-stressed Concrete Steel Strand

1x7 Special Purpose Pre-stressed Concrete Steel Strand

Name: 15.70 PC STRAND
Uploaded: 2025-06-17T07:28:18+08:00
Description: A brief introduction and practical application of 7-strand low-relaxation prestressed steel strand I. Product

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Payment Type:	T/T
Incoterm:	FOB,CFR,CIF
Transportation:	Ocean
Port:	Tianjin Xingang

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Product Description

Product Attributes

Packaging & Delivery

Product Description

Product Attributes

Brand: Chunpeng

Standard: Aisi, Astm, Bs, Jis

Place Of Origin: China

Application: Construction

Whether Alloy: Non-Alloy

Packaging & Delivery

Selling Units	:	Ton
Package Type	:	The roll is wrapped in three layers of waterproof packaging, the roll eyes are facing up and two fumigated sleepers are tied to the bottom with steel belts.
Picture Example	:

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Product Description

A brief introduction and practical application of 7-strand low-relaxation Prestressed Steel strand

I. Product introduction

1. Structure and definition

7-strand steel strand is a spiral prestressed steel made of 7 high-strength steel wires: 1 center steel wire (slightly larger in diameter) and 6 outer steel wires are twisted around to form a stable regular hexagonal structure.

The low relaxation characteristic means that the stress loss caused by stress relaxation of the steel strand under stress is significantly lower than that of ordinary steel strand (such as 1000-hour stress loss ≤2.5%), which is suitable for long-term load-bearing structures.

2. Common specifications and performance

Diameter range: 12.7mm-17.8mm (such as 15.2mm is a typical specification), tensile strength 1720-2230MPa, yield strength (0.2% condition) ≥1500MPa, elongation after break ≥3.5%.

Relaxation performance: At 20℃, when the initial stress is 70% of the nominal strength, the stress loss in 1000 hours is ≤2.5% (the loss rate of ordinary steel strands is about 8%-10%).

2. Core advantages

High strength and high toughness: The breaking force of a single 15.2mm steel strand is about 260kN, which meets the load requirements of large-span structures and has a certain plastic deformation capacity to avoid brittle failure.

Stress stability: Low relaxation characteristics reduce the stress attenuation of the later structure, and there is no need for frequent tensioning, which reduces maintenance costs.

Convenient construction: It can be transported by reel, suitable for standardized anchors (such as clip anchors) and tensioning equipment, and has high construction efficiency.

3. Practical application scenarios

(I) Construction projects

Large-span components

The roof beams of gymnasiums and exhibition halls (span > 30 meters) and crane beams of industrial plants use prestressing to offset load tensile stress and reduce concrete cracks.

High-rise buildings

Unbonded prestressed slabs (such as transfer layers with a thickness of >250mm) and horizontal prestressed tendons in shear walls reduce their own weight and improve crack resistance.

(II) Bridge engineering

Concrete bridge body

Simply supported beams and continuous beams with internal prestressed tendons (such as T beams and box beams), with a span of usually 50-120 meters. Typical cases: urban viaducts and highway bridges.

Special bridge structures

Cables of cable-stayed bridges (single-strand steel strands combined into cable bundles) and main cable strands of suspension bridges (multiple strands of 7-wire steel strands constitute the main cable).

(III) Geotechnical and infrastructure

Slope and foundation pit support

Deep foundation pit anchor cables (such as anchor cables made of 15.2mm diameter steel strands, with an anchoring force of up to 300-800kN), highway slope reinforcement, to resist the lateral pressure of the soil.

Tunnels and water conservancy projects

Prestressed anchors for tunnel linings and circumferential prestressed reinforcement of dam bodies to prevent structural cracking caused by surrounding rock deformation or water pressure.

(IV) Special projects

Nuclear power plants and pressure vessels

The circumferential prestressed tendons of the containment of nuclear power plants must meet high safety and low relaxation requirements to ensure long-term stability of the structure.

Marine projects

Prestressed reinforcement of offshore wind power foundation piles (with zinc-aluminum alloy coating for corrosion protection) and anchoring systems of offshore platforms.

IV. Application cases

Hangzhou Bay Cross-sea Bridge: 15.2mm low-relaxation 7-strand steel strands are used in the box girder body to improve the bridge's wind load and vehicle load resistance through prestressed tensioning.

Transfer layer of high-rise buildings: For example, the thick plate structure of Shenzhen Ping An Financial Center uses 7-strand steel strands as unbonded prestressed tendons, reducing the amount of concrete by more than 30%.

5. Selection and construction points

Specification matching: Select the diameter according to the load calculation (such as 15.2mm is suitable for most bridges, 17.8mm is suitable for super large loads), and match the corresponding anchor (such as M15 clip anchor).

Anti-corrosion treatment: Galvanized and epoxy-coated steel strands are required in open air or humid environments to extend the service life (such as zinc-aluminum alloy coatings are commonly used in coastal bridges).

Tension control: The tension stress is usually 60%-75% of the standard strength value, and super tension is performed (increasing the stress to 80% in a short period of time) to offset the initial relaxation loss.

7-strand low-relaxation prestressed steel strands have become the core material of prestressed systems in modern large-scale projects due to their structural stability and stress durability, especially suitable for scenes with high requirements for safety and durability.

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.