Steel Box Girder

Steel Box Girder – Enterprise-Grade Bridge Superstructure Solutions Product Description

When your infrastructure project demands superior span capability and structural efficiency, Steel Box Girder systems from Shenyang Zhongda deliver proven performance. Our fully welded box girders feature a closed-loop cross-section with exceptional torsional rigidity—several hundred times greater than equivalent I-beams. These components, which are made of high-strength Q345D and Q420D structural steel (≥345MPa yield strength), allow for spans of up to 420 meters while reducing weight by 20% as compared to conventional designs. We service major EPC contractors, such as China State Construction and China Railway Group, with an annual production capacity of 80,000 tons and sophisticated CNC fabrication precision of ±0.1mm. Our prefabricated segments (12-30m) minimize on-site installation time by 50%, while dual anti-corrosion systems provide ≥30 years service life.

Product Advantages

Superior Structural Performance

The closed-section design provides unmatched resistance to torsion and eccentric loads. You benefit from longer spans with fewer piers, reducing your project's environmental footprint and foundation costs by 30-50%.

Accelerated Construction Timeline

Project delivery is revolutionized by our modular prefabrication method. In metropolitan settings, segments arrive prepared for crane-based assembly, reducing traffic disturbance. Construction timetables will be cut in half as compared to conventional cast-in-place techniques.

Advanced Engineering of Materials

We use premium steel with outstanding notch toughness, ASTM A709 Grade 50W/Q355D/Q420. By preventing local buckling, longitudinal and transverse stiffeners guarantee structural integrity under dynamic stresses from heavy traffic or high-speed rail.

Comprehensive Anti-Corrosion Protection

Your investment is protected by C5-M class coating systems or weathering steel technology. Our double-layer treatment (hot-dip galvanizing or advanced spraying) extends service life beyond three decades, even in coastal or industrial atmospheres.

Complex Geometry Capability

Variable cross-section design (1.25-8m depth) accommodates curved alignments and tight horizontal radii. This makes our box girders ideal for urban flyovers and complex highway interchanges where ground space is limited.

Specifications & Customization

Manufacturing & Quality Control

State-of-the-Art Facilities

Our 75,000 m² production facility houses 50-ton crane capacity workshops and 1200-ton plate rolling machines for Steel Box Girder production. You receive components processed on CNC equipment that handles ultra-thick plates up to 300mm with laser-guided accuracy..

Multi-Tier Inspection Protocol

Non-Destructive Testing (NDT)

Every full-penetration butt weld undergoes 100% Ultrasonic Testing (UT) and Radiographic Testing (RT). This detects internal discontinuities before they compromise structural integrity.

Dimensional Precision

Laser tracking technology verifies camber, sweep, and cross-sectional geometry. This ensures perfect fit-up during your site assembly, eliminating costly field adjustments.

Surface Treatment Verification

We conduct blast cleaning to Sa 2.5/3.0 standards, followed by Dry Film Thickness (DFT) testing on all anti-corrosion layers. Your girders arrive ready for decades of maintenance-free service.

Trial Assembly Process

Shop-based pre-assembly of segments mitigates installation risks. We identify and resolve fit-up issues before components reach your construction site.

Material Traceability

Full heat-number tracking for all steel plates and welding consumables is backed by Mill Test Certificates (MTC). You receive complete documentation for compliance verification.

International Certifications

·ISO 9001:2015 Quality Management

·ISO 14001:2015 Environmental Management

·ISO 45001:2018 Occupational Health & Safety

·AWS D1.1/D1.5 Welding Code Compliance

·EN 1090 Structural Steel Execution

Project Cases

Shenyang Dongta Cross-Hunhe River Bridge

Our team fabricated and delivered 18,000 tons of box girder components for this landmark urban infrastructure project. The variable-depth design accommodated the river's navigation requirements while meeting stringent seismic performance criteria.

Jingha Expressway Expansion

We supplied modular girder segments for multiple interchange structures along this critical transportation corridor. Prefabricated delivery enabled nighttime installation, maintaining daytime traffic flow throughout construction.

Heavy Industrial Bridge Systems

Multiple projects for mining and equipment manufacturing clients demonstrate our capability with eccentric loading conditions. These structures support overhead cranes and specialized heavy transport requirements.

Compliance & Certifications

Our manufacturing processes align with international standards:

·AWS D1.5 – Bridge Welding Code for fatigue-resistant details

·AASHTO LRFD – Load and Resistance Factor Design specifications

·EN 1090 – European structural steel execution standards

·JIS G3106 – Japanese rolled steel compliance

·ASTM A709 – American structural steel specifications

All products include comprehensive documentation: English technical drawings, inspection reports, and material certificates suitable for global project requirements.

FAQ

Q: How does the box girder handle internal corrosion?

A: Modern designs incorporate hermetically sealed sections or internal dehumidification systems. By maintaining relative humidity below 40%, we effectively stop corrosion without constant repainting.

Q: Why choose steel over concrete box girders?

A: Steel offers 30-50% reduction in superstructure weight. This leads to smaller foundations, faster crane-based erection, and superior performance in seismic zones. Your project benefits from reduced construction time and lower lifecycle costs.

Q: What is the standard fatigue life?

A: Following AASHTO and Eurocode 3 standards, our girders are designed for 75 to 100 years fatigue life. High-quality weld detailing and NDT inspection ensure this performance target.

Q: Can segments be transported easily?

A: Yes. We design modular segments tailored to truck or barge transport limits. On-site joining uses high-strength friction grip (HSFG) bolts or field welding, depending on your project requirements.

Q: How is thermal expansion managed?

A: Expansion joints are strategically located based on your bridge's length and climate conditions. We provide detailed thermal analysis during the design phase to ensure proper accommodation of seasonal movement.

Contact Us

Ready to discuss your Steel Box Girder bridge infrastructure project? Our engineering team is available to review your technical requirements and provide customized solutions.

Email: Ava@zd-steels.com