Steel Box Girder Bridge – AASHTO LRFD, AWS D1.5, EN 1090-2 EXC4 Compliant

The Steel Box Girder Bridge is a prefabricated closed-section steel bridge superstructure tailored for medium-to-long-span highway, railway and pedestrian engineering projects. Adopting a trapezoidal cross-section with symmetric outward inclined webs, it boasts remarkable flexural performance and ultrahigh torsional stiffness, which makes it the optimal choice for horizontally curved bridge routes. All products strictly abide by AASHTO LRFD, AWS D1.5 and EN 1090-2 EXC4 international codes, gaining official recognition and market access across North America, Europe and worldwide engineering markets.

Standard Compliance

1. AASHTO LRFD Bridge Design Specifications

Authoritative highway bridge design standard in North America that adopts Load and Resistance Factor Design system. It unifies design criteria for straight and curved box girders, clearly defines web slenderness limitation, caps the yield strength of positive bending components at 70 ksi, and specifies the layout of transverse diaphragms, cross frames, lateral bracings to enhance overall structural stability.

2. AWS D1.5 Bridge Welding Code

Universal authoritative specification for steel bridge welding jointly issued by AASHTO and AWS. It regulates the whole welding process covering factory prefabrication and on-site splicing welding, including welding consumables selection, preheating & interpass temperature control, heat input management and fracture risk control plans. All welders hold formal AWS D1.5 certification, and all welding joints are inspected fully per code requirements.

3. EN 1090-2 EXC4 Execution Class

The highest execution grade under European steel construction standards, exclusively used for vital infrastructures and high seismic intensity areas. It enforces ISO 5817 Quality Level B+ welding quality, complete welding technical coordination documents and official CE marking certification, evaluated based on structure risk level, service scenario and production standards.

Structural Design & Engineering Advantages

• •Ultrahigh Torsional Rigidity: Sealed closed cross-section effectively counteracts torsional force and eccentric load, perfectly fits curved bridge construction
• •Optimized Trapezoidal Profile: Uniform inclined webs, reserved sufficient internal space for daily inspection and maintenance; fixed minimum web depth and bottom flange width for standardized construction
• •Wide Load Adaptability: Designed to bear AASHTO HL93, HS series vehicle loads; single span ranges from 10m to 300m, supports single lane, multi-lane and pedestrian-only layouts
• •Fatigue Durability Design: Comply with AASHTO fatigue stress calculation rules, effectively resist long-term cyclic vehicle load, extend service life
  
  

Material Specifications

Prefabrication & Shop Production

All box girders are manufactured in closed workshops under constant controlled environment to stabilize overall quality:

1. 1.Segmented Fabrication: Split into 10–30m standard segments according to shipping and hoisting limits, easy for sea transportation and on-site assembly
2. 2.Integral Full Welding Structure: Top flange, bottom flange, webs, diaphragms and stiffeners are integrally welded, high structural integrity
3. 3.Orthotropic Steel Deck: Equipped with vertical & horizontal stiffeners on top plate, lower dead load and improve load transmission efficiency
4. 4.Prioritized Factory Welding: Core welding works completed in workshop to avoid adverse weather impacts, fully meet AWS D1.5 requirements
5. 5.Reserved Inspection Ports: Two standard access manholes on bottom flange plus reserved holes on solid diaphragms, convenient internal overhaul
   
   

Quality Assurance & Certifications

Every batch of products accepts third-party inspection by SGS, BV and other authoritative institutions, with comprehensive NDT non-destructive testing implemented as required by international codes.

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Conclusion

Steel box girder bridges are the benchmark choice for modern long-span bridge engineering, integrating efficient closed-section structure and top-tier international standard certification. No matter you need AASHTO LRFD compliant bridges for North American highways, AWS D1.5 certified fracture-critical welding structures, or EN 1090-2 EXC4 certified products for European markets, our prefabricated steel box girders consistently deliver reliable safety, long durability and full code compliance.

All products are researched, manufactured and exported by Hangzhou FAMOUS Steel Engineering Co., Ltd. (FASECbuildings), a professional heavy steel structure manufacturer based in China. We boast two decades of industry experience and stable export business covering North America, Europe, Southeast Asia and other global regions. Relying on mature Chinese manufacturing capacity and stringent international standard control, we provide balanced cost, fast delivery and superior workmanship without any quality concessions.

Let’s build safe and durable infrastructure hand in hand. Kindly send your project drawings, span parameters and load demands for customized detailed quotation.