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408-Ton Single-Cell Steel Box Girder: The Workhorse of Highway Bridges
2026-10-19 19:15:46
408-Ton Single-Cell Steel Box Girder: The Workhorse of Highway Bridges
Single-cell steel box girders are the standard superstructure for medium-span highway bridges. Below is data from an actual box girder fabrication quantity summary.
Basic Specs
| Item | Value |
|---|---|
| Box type | Single-cell single box |
| Total width | ~7,850 mm |
| Girder depth | 1,200–1,500 mm (tapered) |
| Segment length | ~13,760 mm |
| Steel grade | Q355MD |
| Total steel weight | 407,569.9 kg (407.6 t) |
| Shear studs | ML15 φ22×200, 14,766 sets |
| Paint area total | ~5,663 m² |
Steel Plate Schedule
| Thickness | Weight (kg) |
|---|---|
| 10 mm | 22,333.6 |
| 12 mm | 18,735.8 |
| 14 mm | 51,175.8 |
| 16 mm | 60,625.2 |
| 18 mm | 80,495.2 |
| 20 mm | 26,508.5 |
| 22 mm | 11,292.1 |
| 25 mm | 17,652.1 |
| 28 mm | 17,118.6 |
| 30 mm | (diaphragms) |
| Total | 407,569.9 |
Structure Details
The box girder consists of:
- Top flange: 25 mm thick, composite with concrete deck
- Bottom flange: 25 mm thick
- Webs: inclined webs, 16–20 mm thick
- Diaphragms: internal diaphragms at supports and midspan
- Shear studs: φ22×200 welded on top flange, composite action
- Access holes: oval access holes at ends for inspection
Advantages
- High torsional stiffness — closed single box resists torsion and skew loads
- Composite design — shear studs connect concrete deck to steel box
- Optimized plate thickness — 10–30 mm plates matched to stress levels
- Modular segments — 13.8 m segments fabricated in shop, spliced on site
- Durable coating system — internal and external paint for long life
Disadvantages / Limitations
- Heavy transport — 408 t total needs segmented delivery and lifting
- Welding intensive — full penetration welds on all main joints
- Interior inspection needed — access holes required for internal checks
- Higher initial cost — box girder costs more than plate girder per meter
- Camber calculation critical — long segments need precise pre-camber
Typical Applications
- Highway overpasses — urban highway crossings
- Urban elevated roads — elevated expressway sections
- River crossings — medium span river bridges
- Curved ramp bridges — highway ramps with horizontal curvature
- Pedestrian bridges — long-span pedestrian crossings
Fabrication Notes
- Q355MD steel plates CNC cut, then welded into box segments
- Shear studs (φ22×200) welded to top flange in shop
- Internal and external surfaces blast cleaned and painted
- Segments transported to site, spliced with high-strength bolts
Single-cell steel box girder — 7.85 m wide, 13.8 m segments, Q355MD, 407.6 t total steel, 14,766 shear studs, composite with concrete deck, built for highway and urban bridges.
**WhatsApp**: +86‑13889862778, +86‑18242444407
**Email**: eddie@zdsteels.com, wells@zdsteels.com
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