Lifting System For Precast Concrete
Precast Concrete Transport Methods
1. Factory Handling & Loading
Roller Lines: Components moved via conveyor rollers to loading docks.
Gantry Cranes: Bridge cranes lift heavy units onto trailers.
Spreaders: Adjustable frames distribute lift forces to prevent cracking.
2. Trailer Configurations
| Trailer Type | Best For | Key Features |
|---|---|---|
| Flatbed Trucks | Standard beams, columns | Simple loading; requires crane at both ends |
| Lowboy Trailers | Tall walls, bulky units | Lower deck height clears underpasses |
| Step-deck Trailers | Extra-tall elements (e.g., bridge girders) | Front deck drop for height clearance |
| Modular Trailers | Mega-elements (over 100 tons) | Multi-axle; hydraulically steered |
3. Securing Components
Timber Dunnage: Wood blocks prevent concrete-to-metal contact.
Nylon Straps/Wire Ropes: Cross-lashed with tensioners to resist shifting.
Corner Protectors: Rubber guards shield edges from strap abrasion.
Keeper Pins: Steel pins lock units to trailer anchor points.
4. Routing & Logistics
Route Surveys: Scout for overhead wires, narrow turns, or weak bridges.
Pilot Vehicles: Escorts with height poles warn of obstacles.
Night Moves: Transport during low-traffic hours in urban areas.
5. Site Reception
Laydown Yard Prep: Level ground with crushed stone; avoid soft soil.
Unloading Sequence: Reverse loading order (last-in, first-out).
Onsite Cranes: Mobile or tower cranes transfer components directly to installation points.
6. Specialized Transport Scenarios
Oversized Loads:
State permits for width/height exceptions.
Police escorts for highway moves.
Fragile Finishes:
Architectural panels shipped vertically on A-frame racks.
Protective films prevent abrasion during transit.
Remote Sites:
Barges for river/island access.
Off-road transporters for rugged terrain.
7. Key Risks & Mitigation
| Risk | Prevention Measure |
|---|---|
| Vibration damage | Air-ride suspension trailers |
| Theft during transit | GPS-tracked shipments + armed guards |
| Weather exposure | Waterproof tarps for rain/snow |
| Component tipping | Lateral bracing frames |
8. Real-World Execution
Highway Bridge Girder Transport:
Fabricate girders with lifting loops.
Load onto multi-axle trailer with 30° approach angle.
Secure with 8-point strapping.
Night move with escort vehicles.
Urban Façade Panel Delivery:
Panels racked vertically on trailers.
"Just-in-time" delivery to match crane schedule.
Unloaded directly into final position.