Professional Post-Tensioning Prestressed Box Girder System for Urban Interchange Ramp Bridge

Product Description

Product Description

Box Girder Prestressing System is an engineering technology system that uses a box-section concrete beam as the carrier. By applying pretensioning or post-tensioning techniques either before or after the concrete hardens, it significantly enhances the structure's crack resistance, stiffness, and load-bearing capacity.

As a core structural system in bridge engineering, the box girder prestressing system consists of prestressing tendons (such as steel strands), anchors, ducts, and tensioning equipment.
 

Our Advantages

Advantages of Box Girder Prestressing Systems:

- High Sectional Efficiency: The box-shaped structure offers high torsional rigidity and bending moment of inertia, making it suitable for long-span, continuous beam, or cantilever construction scenarios.

- Stress Regulation: Prestressing tendons introduce compressive stress before loading, which offsets the tensile stress caused by external loads, delaying crack formation and extending structural life.

- Material Optimization: Compared to ordinary reinforced concrete beams, it reduces cross-sectional dimensions and concrete usage, lowering self-weight by approximately 20%-30% (e.g., composite box girders with corrugated steel webs).

SPECIFICATIONS

Component	Specification	Advantage
Prestressed Strand	Typically, high-strength, low-relaxation steel strands are adopted, arranged longitudinally or transversely along the beam body. Standards: GB/T5224: 9.53,12.7,15.24,17.8mm, ASTM A416/A416:2018: 9.53 , 12.7, 15.24, 15.7mm, EN10138:3 / BS5896: 9.3, 12.5,12.9,15.2,15.7mm.	* Extremely low relaxation rate (relaxation rate ≤2%) * Extremely high yield strength (Yield Strength Ratio >90%) * Good elongation (elongation >5%)
Anchor System	including wedge-type anchors, bearing plate, spiral reinforcement, used for securing prestressing tendons and transferring forces. Available in compliance with the following standards: GB/T14370, JT/T329-2010, TB/T3193-2016, JTG D62-2004, JTJ 041-2000, TB10002.3-1999, TB 10203-2002, JTG/T 3650, FIP-1993, ISO 21725-2:2021.	*anchorage coefficient>95% *custom designed and produced to your specifications/drawings.
Prestressing Ducts	corrugated metal ducts, corrugated plastic ducts	*excellent sealing performance and high ring stiffness.
Tensioning Equipment	incluing jacks,high-pressure oil pumps, and intelligent control systems.	*intelligent control system realizing dual control of force and displacement.

PRODUCT DETAILS

Based on the cross-sectional form, they can be divided into single-cell box girders and multi-cell box girders; based on the construction method, they are mainly divided into pretensioning and post-tensioning.

Comparison dimensions	Pretensioning	Post-tensioning
Tensioning Timing	Tension tendons before concrete placement.	Tension tendons after concrete has hardened.
Force Transfer Mechanism	Transmits prestress via bonding between tendons and concrete.	Transmits prestress via permanent anchors.
Application Scenarios	Prefabrication of small-to-medium standard components in mass production (e.g., precast small box girders).	Cast-in-place long-span and irregular structures (e.g., cast-in-place continuous girders, incremental launch girders).
Anchorage usage	Temporary anchors, which can be reused.	Permanent anchors, which become an integral part of the structure.
Construction Flexibility	Low, dependent on beds and production lines.	High, adaptable to complex terrain and structural forms.

Technical Trend: In modern engineering, post-tensioning has become the mainstream technology for cast-in-place box girders due to its strong adaptability and ability to enable intelligent tensioning.

-Advantages:

Key Technologies & Intelligent Construction:

- Intelligent Tensioning System: Integrating high-precision pressure sensors and cable displacement sensors, the system automatically controls the hydraulic system via PLC. It achieves closed-loop control of tensioning force and elongation, with an error margin controlled within ±1%. Data is uploaded to the cloud in real-time to eliminate human intervention.

- Duct Grouting: Utilizing a vacuum-assisted grouting process to ensure a slurry compactness of ≥95%. This prevents corrosion of the steel strands and enhances structural durability.

- BIM & Monitoring: Applied in projects such as the Songxi River Super Major Bridge, BIM models are used for construction simulation. Combined with intelligent monitoring systems for tower crane stress, deck crane stress, and harmful gases, the technology enables full-process dynamic management and control.
 

APPLICATION

 

Project Name	Structure Type	Construction Technology	Technical Highlights
Tiexi River Bridge (Pujiang, Sichuan)	18×30m Post-tensioned Prestressed Concrete Simply Supported Small Box Girders	Cantilever Erecting + Girder Erection Machine Installation	Adopted a "temporary-permanent integrated" transportation channel. 144 box girders were erected with millimeter-level precision, achieving "zero accidents, zero hidden dangers".
Nanjing Grand Bridge Chenhe River Cable-Stayed Bridge	Approach Steel Box Girder + Prestressed Concrete Composite Structure	Intelligent Deck Crane Lifting	Applied an anchor center positioning device, improving assembly precision by 40% and saving costs of 2.3 million yuan.
Songxi River Super Major Bridge (Hubei)	Corrugated Steel Web Prestressed Composite Box Girder	Segment Prefabrication + Mobile Gantry Assembly	The world's largest span (200m) corrugated steel web composite box girder, reducing self-weight by 30%. Applied intelligent grouting and BIM technology.
Nanjing Grand Bridge on Huning High-speed Railway	Single-cell Single-box Variable Section Prestressed Concrete Continuous Girder	Swing Construction	97.5m girder was rotated 60° counterclockwise with precise positioning, solving the safety challenge of construction above operating railway lines.

Certifications

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FAQ

1. What is your delivery time?
We offer fast delivery: stock items ship in 7-15 days, while custom orders typically take 15-30 workdays, depending on your specific quantity.

2. How do you guarantee product quality?
Quality is verified through Mill Test Certificates (MTC) included with every shipment, and we fully support third-party inspections for your peace of mind.

3. Are there any hidden costs?
No. Our quotations are transparent and all-inclusive, ensuring you won't encounter any unexpected or additional fees.
 
4. Do you provide samples?
Yes, we provide samples for a nominal fee of $1; you just need to cover the freight cost to evaluate our quality firsthand.

5. What payment terms do you accept?
We accept T/T at sight and L/C, as well as Cash and Western Union. Please contact us if you require alternative arrangements.

6. What is your MOQ?
Our standard MOQ is usually one container, but we offer flexibility for specific items; please get in touch to discuss your requirements.

7. Can you produce according to my drawing?
Absolutely. We specialize in OEM and custom manufacturing, and our engineering team can produce exact specifications based on your drawings.