Prestressing Corrugated Duct Price Factors and Purchasing Guide for Engineering Projects

发布于 2026-10-14

Hengshui Zhanhe Engineering Rubber Co., Ltd. supplies prestressing corrugated duct and related engineering rubber products to contractors, distributors and infrastructure projects worldwide. The permanent duct embedded in post-tensioned concrete that carries tendon installation, grouting and long-term corrosion protection in one product.

This article explains the working principle, main types, typical applications, installation points, selection criteria, standards and frequently asked questions about prestressing corrugated duct, and is intended for engineers, purchasers and project managers.

1. What Is Prestressing Corrugated Duct?

The permanent duct embedded in post-tensioned concrete that carries tendon installation, grouting and long-term corrosion protection in one product.

Working principle: The product works through elastic deformation and mechanical interlock to provide reliable sealing or load transfer.

2. Main Types

• Plastic corrugated duct (SBG) in HDPE for aggressive environments and long design life
• Metal corrugated duct (JBG) wound from galvanised steel strip for stiff, economical short tendons
• Flat duct for thin slabs and transverse prestressing in deck panels
• Heavy-wall plastic duct for heavy cover loads and small curvature radii

3. Typical Applications

• Longitudinal tendons in precast box girders and railway T beams
• Web and transverse tendons in curved urban interchange box girders
• Internal tendons crossing the joints of segmentally erected bridges
• Circumferential prestressing in tank walls and transfer beams in large public buildings

4. Installation and Construction Points

1. Inspect deliveries and reject flattened, split or badly cut pipe
2. Set out and tie locating cages at not more than 0.8 m on straight lengths and 0.5 m on curves
3. Thread the duct after the cage is shaped, using a conical pulling head
4. Join with oversized couplers and seal them with tape or heat-shrink sleeving
5. Fit anchor plates, spiral reinforcement and grout and vent pipes before closing the formwork
6. Keep vibrators off the duct while placing concrete and prove every duct with a gauge after initial set

5. Selection Guide

• Confirm the design displacement, load grade and service environment before ordering.
• Select material grade according to temperature range, medium and durability requirements.
• Provide drawings or a specification list so that the manufacturer can verify sizes.

6. Standards and Quality Control

Prestressing Corrugated Duct is manufactured and inspected according to applicable national and industry standards. Hengshui Zhanhe Engineering Rubber Co., Ltd. carries out batch inspection before delivery, and inspection certificates together with third-party test reports (where required by the project) can be provided.

Typical standards applied to this product family include Chinese national and transportation industry standards; equivalent international standards can be referenced upon request.

7. FAQ

Q: Is a larger duct safer?

A: Not necessarily. Oversized ducts add grout volume, make tendon eccentricity harder to control and reduce local section stiffness. The accepted rule is a clear duct area of two to two and a half times the tendon net area.

Q: Why is ring stiffness specified?

A: Concrete pressure during placing can ovalise or collapse a weak duct, which either blocks threading or forces the contractor to chase the duct out of hardened concrete. Plastic duct is normally specified at not less than 6 kN per square metre.

Q: Can metal duct be used in coastal bridges?

A: Galvanising is consumed quickly by chlorides, so plastic duct is preferred there. Combine it with increased cover and denser concrete rather than relying on duct choice alone.

Q: How serious is incomplete grouting?

A: Voids remove the alkaline protection around the tendon, corrosion follows and section loss can be significant. Prevent it with vacuum assisted grouting, strict grout testing and verification of filling by impact echo or endoscopy.

8. Price Factors

Costs are driven by resin price movements, material per metre set by diameter and wall thickness, freight which rises sharply for long fixed lengths into remote sites, tooling amortisation for flat and heavy-wall sections, and third party testing for ring stiffness. Standard 70 mm plastic duct is usually quoted at 8 to 18 CNY per metre against roughly 5 to 12 CNY for metal duct.

Packing: standard export packing (woven bags, pallets or wooden cases). Delivery terms: EXW, FOB, CFR, CIF or DAP as agreed. Payment terms: T/T, L/C or other terms subject to negotiation.

9. Why Work With Hengshui Zhanhe Engineering Rubber Co., Ltd.

• Manufacturer based in Hengshui, Hebei — the engineering rubber industry cluster in North China, with in-house production and inspection.
• OEM and ODM supported: sizes, hardness, profiles and packaging can be customized to project or market requirements.
• Batch inspection before shipment; certificates of conformity and third-party test reports available when required.
• Technical support for selection, shop drawings and installation guidance, with export packing and worldwide logistics arrangement.

10. Contact and Quotation

For specification sheets, samples, pricing or project support, please contact Hengshui Zhanhe Engineering Rubber Co., Ltd.. Email: 150051331@qq.com · Tel/WhatsApp: +86-13833886677 · Factory: No.168, Zhangtuantuo Village, Dengzhuang Town, Taocheng District, Hengshui, Hebei, China. We reply to export enquiries within 24 hours on working days.