Life monitoring techniques for core components of single-beam bridge cranes

1. Metal structure: monitoring of fatigue cracks in main beams and end beams

Key monitoring points

Main beam camber: Regularly measure the camber of the main beam mid-span using a laser range finder or total station. If the measured value is less than 70% of the design value (for example, if the design camber is S/1000 and the measured value is less than 0.7S/1000), be cautious of metal fatigue.

Weld quality: Use magnetic particle flaw detectors or penetrant flaw detectors to inspect high-stress areas such as the connecting welds between the main beam and the end beam, as well as the mid-span welds, with a focus on detecting defects such as cracks and porosity.

Corrosion degree: Measure the thickness of the lower cover plate and web plate of the main beam using an ultrasonic thickness gauge. If the corrosion amount exceeds 10% of the original thickness, the remaining lifespan needs to be evaluated.

Monitoring cycle

Routine inspection: Visually inspect the surface of the main beam for any deformation or cracks once a week.

Professional inspection: Conduct non-destructive testing of welds once every six months, and perform camber measurement and thickness testing once a year.

II. Transmission system: monitoring the wear of reducers, couplings, and wheels

Key monitoring points

Reducer:

Oil leakage detection: Inspect the sealing performance of the reducer casing. If the oil leakage exceeds 5mL/h, the sealing components need to be replaced.

Abnormal noise analysis: Monitor the vibration frequency of the reducer during operation using a vibration analyzer. If the vibration amplitude exceeds 20% of the reference value, there may be gear wear or bearing damage.

Coupling:

Wear of elastic rubber ring: Check the rubber ring of the elastic pin coupling for cracks or permanent deformation. If the wear exceeds 30% of the original thickness, it needs to be replaced.

Wear of gear ring: For tooth-type couplings, measure the tip clearance. If the clearance exceeds 15% of the design value, repair or replacement is required.

Wheel:

Tread wear: Measure the diameter of the wheel tread with a caliper. If the wear exceeds 5% of the original diameter, the wheel needs to be replaced.

Rail gnawing detection: Check the track deviation using a track straightness measuring instrument. If the deviation exceeds ±5mm, adjust the position of the wheels or the track.

Monitoring cycle

Routine inspection: Visually inspect the reducer for oil leakage and the coupling for looseness once daily.

Professional inspection: Conduct vibration analysis once every quarter and perform wheel tread measurement once every six months.