What a Steel Girder Bridge Manufacturer Provides
A prefab sports venue wholesale produces the structural steel components that form the load-carrying superstructure of a bridge-girders, trusses, deck systems, cross-frames, and connection assemblies. Jidian Construction Materials Co., Ltd. manufactures modular steel girder and arch bridges from Q345qC/Q370qC bridge steel per GB/T 714, handling single spans from 20 to 80 meters. Components are shop-fabricated in transportable modules (max 12m length per segment for container shipping), then bolted or field-welded on site. Each bridge is custom-engineered to your span, load, deck width, and local bridge design code.
Bridge Types: Box Girder, Truss, and Arch Configurations
Different bridge types serve different span ranges, load requirements, and aesthetic goals:
| Bridge Type | Typical Span | Configuration | Best For |
|---|---|---|---|
| Box girder | 20–60m | Single-box or twin-box | Highway bridges, curved alignments |
| Pratt/Warren truss | 30–80m | Through or deck truss | Long spans, river crossings |
| Steel arch | 40–80m | Tied or true arch | Civic landmarks, aesthetic bridges |
| Multi-span continuous | 20–80m per span | Expansion joints | Long crossings over valleys/rivers |
Bridge Steel Grades and Material Properties
Bridge structures require steel with guaranteed notch toughness and weldability. Jidian uses Q345qC and Q370qC bridge steel per GB/T 714. The "q" designation indicates bridge-grade steel with controlled chemical composition for welding and impact toughness. The "C" quality level guarantees Charpy V-notch impact energy at -20°C, making it suitable for cold-region applications. For projects requiring other steel grades-such as ASTM A709 for AASHTO-compliant bridges or EN 10025 grades for Eurocode-confirm availability during inquiry.
Each steel batch comes with mill certificates documenting chemical composition, mechanical properties, and impact test results. These certificates are part of the material traceability dossier included with every bridge shipment.
Load Ratings and Design Code Compliance
Jidian engineers bridge structures to the design code applicable to your project location:
- Chinese GB 50009/50017: Load codes and steel structure design codes. Highway load Grade-I.
- AASHTO LRFD: Load and Resistance Factor Design for US and international projects. HS-20 or HL-93 loading.
- Eurocode EN 1991/1993: Actions on structures and design of steel structures. LM1 load model.
- British Standards BS 5400: Steel, concrete and composite bridges. HA/HB loading.
Specify your project's governing code during inquiry. The engineering team provides stamped structural calculation reports, load ratings, and erection plans compliant with your local bridge design code.
Modular Shipping and Container Optimization
A key advantage of modular steel bridges over precast concrete is shipping efficiency. Jidian's bridge segments are limited to 12m length × 3.2m width for standard 40ft container loading. This drastically reduces ocean freight cost versus monolithic concrete beams, which require special transport and handling. Oversized segments can be shipped via 40ft OT containers or breakbulk vessels when project requirements demand.
Segments are marked with part numbers and match-marked for field assembly. Bolted connections are designed per ISO 10721 with Category 71–90 fatigue detail classification for highway loading. For projects where field welding is required, welding procedures and welder qualifications are documented per ISO 15614-1 and ISO 9606.
Anti-Corrosion Systems for Bridge Longevity
Bridges face some of the harshest corrosion environments-moisture, de-icing salts, marine atmospheres. Jidian applies a multi-layer anti-corrosion system achieving 30+ year maintenance-free service in C4/C5 marine environments per ISO 12944:
- Surface preparation to Sa 2.5 (ISO 8501-1)-near-white metal blast.
- Thermal spray zinc (≥150μm)-metallized zinc layer bonded to the steel surface.
- Epoxy sealer-penetrates the zinc layer to seal pores.
- Polyurethane topcoat-UV-resistant finish for weathering protection.
Coating thickness is measured at multiple points on each component and documented in the shipment dossier. For bridges in especially aggressive environments (C5-M), the system can be upgraded with additional sealer coats.
Welding Qualification and Non-Destructive Testing for Bridges
Bridge fabrication demands the highest welding standards. Jidian holds the China Steel Structure Manufacturing Special Level Qualification-the highest in the field. Welding procedures are qualified to ISO 15614-1, and all welders carry ISO 9606 certifications. For bridge girders, 100% of full-penetration butt welds undergo ultrasonic testing (UT) per GB/T 11345, with 10% radiographic testing (RT) spot checks. Magnetic particle inspection (MT) is applied to all fillet welds at fatigue-critical details.
Jidian also holds the Italy Welding Procedure Qualification Certificate, enabling CE-marked bridge components for European projects. Each bridge shipment includes a complete material traceability dossier: mill certificates, weld maps, NDT reports, and coating thickness records.
Installation and Erection Planning
A typical 40m single-span girder bridge can be erected in 7–15 days after foundation completion, versus 60–90 days for cast-in-place concrete. Jidian provides erection sequence drawings, lifting plans, and on-site engineer supervision for bridges above 30m span. The modular approach also allows future span extension or bridge relocation if river alignments change.
For multi-span continuous bridges, temporary supports and launching methods are designed case by case. Field welding, when required, follows the same procedures and NDT protocols as shop welding. Final inspection includes dimensional verification, bolt torque checks, and coating touch-up verification.
Packaging, Shipping, and Documentation
Bridge segments are packaged with steel strapping and timber dunnage to prevent shifting during transport. Small parts-bolts, nuts, washers, splice plates-go in wooden crates labeled with part numbers. Standard shipments use 40ft containers from Xiamen port. Each shipment includes:
- Material traceability dossier (mill certificates, chemical analysis, mechanical test results)
- Weld maps and NDT reports (UT, RT, MT)
- Coating thickness records
- Shop drawings and erection sequence plans
- Structural calculation reports and load ratings
Cooperation Process: From Bridge Inquiry to Installation
- Inquiry: Provide span length, deck width, highway load class, design code, environmental conditions (corrosion category, temperature range), and foundation type.
- Design: Structural calculations, load ratings, and erection plans within 5–10 working days. Free of charge before production.
- Quotation: Detailed price including steel tonnage, coating system, hardware, and packaging.
- Production: Shop-fabricated modules with ±2mm tolerance. Complete NDT documentation.
- Quality control: UT, RT, MT, coating thickness, dimensional checks.
- Packing and shipping: 40ft containers from Xiamen, with full documentation dossier.
- Installation: Erection sequence drawings, lifting plans, on-site engineer supervision for spans above 30m.
- After-sales: 30-year design life, 2-year workmanship warranty, ongoing structural health monitoring consultation.
Common Risks in Bridge Steel Procurement
- Wrong steel grade: Using structural steel (Q345B) instead of bridge steel (Q345qC) saves cost but lacks guaranteed notch toughness at low temperatures. Always verify that bridge-grade steel per GB/T 714 or equivalent is specified.
- Inadequate fatigue detailing: Highway bridge connections must be designed for fatigue. Bolted connections should follow ISO 10721 Category 71–90 detail classification. Ask for fatigue analysis in the calculation report.
- Missing NDT documentation: Bridge reviewing authorities often require UT and RT reports. Confirm that the manufacturer provides complete NDT records with every shipment, not just on request.
- Coating system under-specification: A simple paint system will not last 30 years in C4/C5 environments. Verify that the anti-corrosion system includes thermal spray zinc, not just epoxy primer.
- Shipping size miscalculation: Segments exceeding 12m × 3.2m require OT containers or breakbulk, significantly increasing freight. Confirm container compatibility during design.
FAQ
Q: What span lengths can you manufacture?
A: Single spans from 20m to 80m. For longer crossings, we design multi-span continuous girder or arch configurations with expansion joints.
Q: What bridge design codes do you comply with?
A: We engineer to Chinese GB 50009/50017, AASHTO LRFD, Eurocode EN 1991/1993, or British Standards BS 5400, depending on your project location.
Q: Can you provide shop drawings and calculation reports for local review?
A: Yes. We deliver stamped structural calculation reports, material specifications, weld maps, NDT reports, and full shop drawings for your reviewing authority.
Q: How are bridge modules shipped?
A: Segments are limited to 12m × 3.2m for standard 40ft container loading. Oversized segments can be shipped via 40ft OT containers or breakbulk vessels.
Q: What anti-corrosion system do you use?
A: Thermal spray zinc (≥150μm) + epoxy sealer + polyurethane topcoat, achieving 30+ year maintenance-free service in C4/C5 marine environments per ISO 12944.
Q: Do you offer on-site installation supervision?
A: Yes. For bridges above 30m span, we dispatch qualified engineers to supervise erection, welding, and final inspection at your site.
Q: What is the expected design life of the bridge?
A: 30-year design life with the standard coating system. The structure itself is designed for 50+ year service per code requirements.
Q: Can I request OEM manufacturing?
A: Yes. We offer full OEM/ODM services including custom branding on components, packaging, and documentation.
Q: What are the payment terms?
A: T/T (30% deposit, 70% before shipment) or L/C at sight. Trade assurance supported via Alibaba.
Q: What steel grades do you use for bridge girders?
A: Q345qC/Q370qC per GB/T 714, with guaranteed notch toughness at -20°C. For projects requiring ASTM A709 or EN 10025 grades, confirm availability during inquiry.
