A double girder overhead crane is a kind of heavy lifting equipment widely used in factories, warehouses, harbors, and other places. It consists of two parallel main girders, end girders, lifting trolleys, and an electrical control system. Compared with the single girder structure, it has a higher load carrying capacity (usually 5~550 tons), and the structure and installation process are more complicated, usually requiring strict technical requirements. In this article, we will introduce the installation process of how to build a double girder overhead crane in detail by combining the industry standard and actual engineering experience. Please continue reading below.
Step I: Pre-Construction Preparation
The installation of a double girder overhead crane is a systematic project, covering mechanical, electrical, civil construction, and other specialized fields. Before formal installation, sufficient preparation work must be done, mainly including the following:
1. On-Site Investigation And Development Of Construction Programs
Confirmation of basic parameters: detailed verification of the design drawings and the actual working conditions on site, confirming the span, lifting height, column bearing capacity, and other key parameters.
Technical documents: Prepare the general assembly diagram, electrical schematic diagram, installation manual, and quality certification documents.
Formulation of construction program: including lifting process, safety measures, and emergency plans.
2. Inventory materials and prepare installation tools
Inventory the main components, such as main beams, end beams, traveling mechanism, etc., according to the packing list.
Prepare special lifting equipment and installation tools: lifting equipment such as an automobile crane, a gantry crane, etc. Installation tools include a laser level meter (accuracy 0.02mm/m), a latitude and longitude meter, a hydraulic torque wrench (range 1000N-m), and welding equipment.
In addition, please pay attention to equip safety protection facilities, set up a warning area, wear a helmet, safety belt, fall arrester, safety rope, and other equipment for working at height.
Step II: Track Installation
Double-beam bridge cranes usually use QU-type or P-type tracks. The installation accuracy directly affects the equipment's running stability and wheel rim wear.
1. Track installation standards
Before installing the track, it is necessary to conduct a basic acceptance, including testing the track beam concrete strength (≥C30), measuring the position deviation of the embedded parts (≤5mm), and checking the flatness of the track pad (≤1mm/m).
Press plate fixing: Use high-strength bolts to fix the track, with a spacing of ≤600mm.
Welding fixation (optional): Suitable for heavy cranes, a low-stress welding process is required.
4. Track electrical safety
Grounding treatment: Both ends of the track are reliably grounded, and the grounding resistance is ≤4Ω.
Anti-collision buffer: Stoppers are installed at the ends of the track to prevent the crane from derailing.
Step III. Assembly and hoisting of the main structure of the crane
The main beam and end beam of the double-beam overhead crane are usually transported separately and need to be assembled on site.
1. End beam assembly
Assemble the end beam on a flat ground and adjust the parallelism of the wheels (deviation ≤ L/1000, L is the measured length).
Use a torque wrench to tighten the high-strength bolts according to the standard (such as an M20 bolt torque is about 400N·m).
2. Main beam hoisting
Single beam hoisting method: Lift the main girder on one side first, adjust the level and fix it, then lift the other side.
Integral hoisting method (applicable to a small double-beam overhead crane): complete the connection between the main beam and the end beam on the ground and hoist as a whole.
Precautions for hoisting: Use a balance beam to avoid deformation of the main beam. And install temporary supports immediately after hoisting to prevent overturning.
3. Connection between the main beam and the end beam
Use high-strength bolts to connect, and tighten in the order of initial tightening (30% torque) → final tightening (100% torque) → re-tightening.
Check the camber of the main beam (usually S/1000, S is the span) to ensure that it meets the design requirements.
Step Ⅳ. Electrical system installation and commissioning
1. Safe busbar installation
The busbar straightness error is ≤±2mm/m, and the collector has good contact.
The three-phase insulation resistance is ≥1MΩ to avoid short circuit risks.
2. Control cabinet and motor commissioning
Wire according to the electrical drawings to ensure that each limit switch (hoisting, trolley, and car) is sensitive.
Adjust the brake clearance (0.5~0.8mm) and test the brake slippage (≤S/100).
Step V. Machine commissioning and acceptance
1. No-load test
The trolley and car run 3 times throughout the whole process to check for jamming and abnormal noise.
The hoisting mechanism rises and falls throughout the whole process to test the reliability of the limit switch.
2. Static load test
Load 1.25 times the rated load, hover for 10 minutes, and check the deflection of the main beam (≤S/800).
Check for permanent deformation after unloading (≤S/1000).
3. Dynamic load test
Load 1.1 times the rated load and perform compound actions (lifting + trolley/trolley operation).
Test the braking performance to ensure that there is no abnormal vibration.
4. Acceptance documents
Installation record, commissioning report, special equipment inspection certificate (issued by the local quality inspection department).
Verify the insulation performance of electrical circuits
Electrical Insulation
Lubricate bearings, gears, and wire ropes
Periodic Maintenance
Monthly Maintenance
1. Check rail fastening condition 2. Adjust the brake system
Quarterly Maintenance
1. Comprehensive inspection 2. Conduct a load test if necessary
Annual Maintenance
Operators must hold a valid certification
Operator Training
Certification Requirement
Operators must hold valid certification
Equipment Familiarization
Must understand equipment parameters and emergency procedures
Prohibited Operations
1. No overloading 2. No diagonal pulling 3. No emergency stopping
Conclusion
The above is a detailed guide on how to build a double girder overhead crane, following the construction in strict accordance with the specifications. It is recommended to choose a professional team with special equipment installation qualifications for installation and regular maintenance to ensure safe production. Weihua, as a famous overhead crane manufacturer and factory in China, provides a one-stop lifting solution and installation service. For technical support or on-site installation service, you can choose to contact our professional team.
EN 
AR 
DE 
ES 
FR 
PT 
IT 
MN