Crane Configuration for Steel Bridge & Building Construction
Crane configurations for the steel bridge and building sector must cover three key applications: steel box girder fabrication, steel truss assembly, and steel structure workshop erection. For steel box girder fabrication, we recommend an MG gantry crane (lifting capacity 32–100t, span 40–45m); for steel truss assembly, a QD double-girder bridge crane (10–50t); and for on-site workshop erection, a mobile gantry crane or truck crane. Kelude offers dedicated crane maintenance programs for the steel structure industry.
The steel bridge and building sector is one of the most crane-intensive industries — from plate unit welding and assembly of steel box girders to segment turnover and flipping, from truss member assembly to complete hoisting, and from steel column and beam erection to cladding panel lifting in workshop buildings, every stage demands reliable lifting equipment. Steel box girder segments typically weigh between 50t and 300t, steel truss spans can reach up to 100 meters, and structural members in workshop buildings can be as long as 30 meters. This article provides crane configuration recommendations across three primary scenarios: steel box girder fabrication, steel bridge assembly, and steel structure workshop erection.
Steel Structure Crane Configuration Comparison
| Comparison Parameter | Steel Box Girdermanufacturing | steel truss Assembled | Steel Structure Workshopinstallation |
|---|---|---|---|
| recommended model | MG Type Gantry Crane | QD Typedouble-girder bridge crane | Mobile Gantry Crane/truck crane |
| lifting capacity range | 32~100t | 10~50t | 10~50t |
| Span/jib length | 40~45m | 22~36m | 20~40m(truck crane) |
| Lifting spreader Solution | Spreader Beam+double lifting points | Multi-Lifting point Balancer Tooling | Lifting Sling+Hook |
| Positioning Accuracy | ±5mm(Assembly Welding) | ±3mm(Assembled) | ±20mm(installation) |
| reference price | 50~20010K CNY | 20~8010K CNY | 15~6010K CNY |
Overhead Cranes for Steel Box Girder Fabrication: Plate Assembly and Segment Tipping
Steel box girders form the primary load-bearing structure of bridges. The manufacturing process involves steel plate pretreatment, cutting, panel unit assembly and welding, sub-segment assembly, full segment assembly, segment tipping and turning, painting, and delivery. Steel box girder segments weigh 50–300t, measure 12–30m in length, and 3–8m in width:
- Panel assembly and welding area: LD/LH type overhead cranes (10–20t) are recommended for assembly, welding, and transport of top plates, bottom plates, and web plates. Typically 3–6 units are installed per bay.
- Segment assembly area: QD type double-girder overhead cranes (50–100t) or MG type gantry cranes (50–200t) are recommended, with a work duty classification of A5 to A6 and spans of 30–50m.
- Segment tipping: Steel box girder segments require tipping during welding (from flat to overhead position). Two overhead or gantry cranes are recommended to work with a turnover jig—one main crane carries the segment's primary weight while the other controls the tipping attitude via master-slave control for synchronized rotation.
- Twin trolley configuration: A twin-trolley gantry crane is recommended for the assembly area—a main trolley (large tonnage for segment hoisting) plus an auxiliary trolley (smaller capacity for plate and fitting handling)—allowing simultaneous operations without interference.
- Reference price: MG type 100t/40m twin trolley: approximately $220,000–$415,000; QD type 50t/30m: approximately $89,000–$148,000.
Steel Truss Assembly Cranes: Hoisting Ultra-Long-Span Members
Steel trusses (used in railway bridges, highway bridges, and combined rail-road bridges) are assembled from individual members—chord members, web members, and lateral bracing—ranging from 6–24m in length and 1–15t in weight. Once fully assembled, a complete truss can weigh 500–2,000t, requiring large gantry cranes or floating cranes for the final lift:
- Assembly yard: Multiple QD overhead cranes (10–32t) handle unloading, storage, and positioning of members on assembly jigs. A configuration of 4–8 QD cranes per bay, spaced 15–20m apart, is recommended for parallel operation.
- Complete truss lift: For ultra-long-span steel trusses (100–200m span), dual-crane lifting is typically employed—either two large gantry cranes or one gantry crane paired with a truck crane or crawler crane—coordinated through master-slave control for synchronized hoisting and travel.
- Multi-crane tandem lifting system: 2–4 cranes are linked via fiber optic or PROFINET communication for master-slave synchronization, achieving a synchronization accuracy of ±10mm. Hardwired emergency stop interlocks connect all cranes—if any crane triggers an emergency stop, all cranes in the tandem system halt simultaneously.
- Precise positioning: Overhead cranes in the assembly jig area are recommended to feature variable-frequency speed control (creep speed of 0.5–2m/min) to meet precise member alignment requirements (positioning accuracy ≤5mm).
Workshop Cranes for Steel Structure Fabrication: Cost-Effective Multi-Crane Solutions
Steel structure workshop fabrication (portal frames, space frames, and tubular trusses) primarily involves H-beam members (columns and rafters) along with lightweight components such as purlins and bracing. Members typically measure 6–30m in length and weigh 0.5–10t each. A multi-crane configuration of light-duty overhead cranes is recommended for the workshop:
- Recommended model: LD type single-girder overhead crane (5–20t) with spans of 18–30m and a work duty classification of A4 to A5.
- Multi-crane configuration: Typically 4–8 LD cranes are installed per bay, spaced 12–18m apart. Each crane is equipped with an infrared and laser-based anti-collision system.
- Control mode: Radio remote control allows the operator to walk alongside the load on the workshop floor for optimal visibility.
- Speed configuration: Crane travel speed of 20–30m/min is recommended to maximize long-distance handling efficiency across the workshop, paired with two-speed hoisting (5/0.8m/min).
- Reference price: LD type 10t/24m: approximately $15,000–$24,000 per unit.
Kelude Service Advantages for the Steel Structure Industry
- Tipping and turning solutions: Kelude Heavy Industry offers a complete dual-crane lifting and turnover jig system for steel box girder and steel truss tipping operations. Two cranes operate through master-slave control for synchronized lifting and differential speed control for controlled tipping angles. Real-time monitoring of each crane's lifting capacity prevents off-center loading throughout the tipping process.
- Twin-trolley gantry cranes: Kelude's twin-trolley MG type gantry cranes (50–200t) feature main and auxiliary trolleys that operate independently or in tandem. The main trolley handles heavy-load lifting while the auxiliary trolley manages secondary tasks, allowing a single gantry crane to perform two work functions and maximizing equipment utilization.
- Multi-crane anti-collision: Steel structure workshops often have up to 8 overhead cranes in a single bay. Kelude's multi-crane anti-collision system (three-level infrared + laser + PLC protection) supports management of up to 8 cranes per bay with adjacent crane spacing detection accuracy of ±10mm.
FAQ
Q: What should be considered when using a gantry crane for steel box girder fabrication?
A: MG-type gantry cranes are typically used for steel box girder fabrication. Key considerations: Span matching — the crane span must cover the girder width plus welding platforms on both sides; for example, a 30 m wide girder requires a crane with a 40–45 m span. Tonnage safety margin — select capacity based on the heaviest girder segment multiplied by 1.3 to account for tooling and spreader weight. Lifting speed — slow-speed precise positioning at no more than 2 m/min is required during assembly and tack welding, while fast-speed lifting of at least 5 m/min is needed during flipping operations to maintain productivity. Double lifting points — due to the high length-to-width ratio of box girders, dual lifting points or a spreader beam is essential to prevent load eccentricity. Kelude's gantry cranes for the steel structure industry come standard with variable frequency dual-speed control and a spreader beam.
Q: How do you prevent lifting deformation of extra-long members during steel truss bridge fabrication?
A: Self-weight deflection of extra-long members (e.g., chord members 12–24 m, web members 8–15 m) during lifting can significantly compromise assembly accuracy. Solutions: Multi-point lifting (three or four points) — use a spreader beam to distribute lifting points, with positions calculated based on the member's moment of inertia of section to avoid excessive mid-span bending moment. Auxiliary struts — members with high slenderness ratios should be fitted with rigid auxiliary struts to prevent buckling. Pre-camber — calculate deflection based on the member's self-weight and build in a reverse pre-camber during fabrication to compensate for lifting deformation. Kelude can customize multi-point lifting solutions based on the specific process requirements of steel structure fabricators.
Q: Should a truck crane or a gantry crane be used for steel structure workshop installation?
A: It depends on site conditions and the construction phase. Truck crane advantages: mobility, no rail requirement, and suitability for dispersed lifting at multiple workstations — making it the mainstream choice for steel structure erection sites. Gantry crane advantages: fixed coverage of a designated work area, higher control precision, suitability for repetitive lifting operations, and lower operating costs (electric vs. diesel drive). Recommended combination: use truck cranes (25–80 t class) for site preparation and occasional lifts, and install temporary rails with a gantry crane (10–50 t, 20–30 m span) in the main lifting zone to establish a fixed-station flow line. Kelude offers demountable mobile gantry crane solutions for steel structure construction sites.
Q: What are the key routine maintenance points for cranes in the steel structure industry?
A: The steel structure industry involves high dust levels, welding spatter, and frequent lifting cycles. Maintenance priorities: Wire rope — inspect weekly for wire breaks and wear; welding spatter can easily burn the rope surface, so install fire-resistant protective covers in spatter zones. Crane rail — check track gauge and straightness monthly; weld slag falling into the rail channel accelerates wheel wear. Brake — inspect brake clearance and friction lining thickness daily; for precise load positioning, friction lining wear must not exceed one-third of the original thickness. Motor cooling — summer workshop temperatures can reach 40–50 °C; clean the motor cooling air duct monthly to prevent dust buildup and overheating. Kelude provides specialized crane maintenance programs for the steel structure industry, including semi-annual and annual inspections.
