How bridges get built · Steel erection · Field splices: bolted and welded connections
Also called: bolted splice, welded splice, high-strength bolting, site welding
How it is done
- Bolted: align the girders with drift pins on temporary supports, fill the holes with bolts, snug-tighten, then tension by turn-of-nut, calibrated wrench or tension-control bolts; inspect with a skidmore and inspection torque.
- Welded: fit-up with run-on tabs, preheat to the specified temperature, weld flanges then webs in the sequence that controls distortion, ultrasonic test all butt welds.
- Protect the splice against corrosion: paint touch-up or weathering steel detailing.
Where it fits
- All steel bridges; welded splices for orthotropic boxes and aesthetics, bolted for everything else.
Where it does not
- Welding in wind or rain without shelters; mixing bolt lots without tests.
Plant, pace and money
PlantBolt tensioning tools, welding sets with preheat, shelters, NDT.
ProductivityA bolted splice with 300 bolts in a shift; a welded box splice in one to three days.
CostBolted splices USD 20-40 per bolt installed; welded splices USD 2,000-6,000 per flange.
Risks and controls
What goes wrong
- Under-tensioned bolts, hydrogen cracking in thick welds, distortion pulling the geometry.
Quality assurance
Bolt tension verification tests each lot, weld procedure qualification, UT and MT records.
Examples
Every steel splice in the game's steel erection animations is assumed bolted.
Related methods
Crane erection of steel girdersLaunching of steel girders and boxesCantilever erection of steel (derrick and lifting frames)
Further reading
RCSC Specification for Structural Joints · AWS D1.5 Bridge Welding Code · EN 1090-2