Application and Operational Guidelines for Grab Cranes in Metro Construction

Evolution of Grab Crane Usage

Originally prevalent in port construction for their efficiency, grab cranes now play an increasingly vital role in urban rail transit projects. The growing demands of metro construction have elevated both technical specifications and economic considerations for muck removal equipment.

Optimal Equipment Selection

Choosing appropriate grab cranes based on project specifics delivers dual benefits:

• Significant cost reduction
• Enhanced operational efficiency

These cranes excel in vertical shaft excavation, offering distinct advantages over conventional hoppers. While hoppers require external power for loading/unloading, grab systems perform these functions autonomously through their articulated mechanisms comprising pulleys, support frames, and jaw plates

Three Core Components

Modern grab cranes incorporate:

Structural Framework

• Vertical columns and cross bracing
• Diagonal supports
• Main and auxiliary trolleys

Drive System

• Drum assemblies and motors
• Speed reducers and brakes
• Primary grab unit with secondary hook

Electrical Systems

• Control cabinets and power distribution units
• Circuit networks

Critical Operational Protocols

As specialized equipment, grab cranes require:

• Mandatory registration with regulatory authorities
• Strict compliance with safety procedures

Essential Safety Measures
During empty grab descent:

• Never rush the lowering process
• Rapid descent generates destructive inertial forces
• Potential consequences include:
  • Trolley beam deformation
  • Derailment incidents
  • Costly repairs and project delays

Industry Trends and Future Prospects

Growing government investment in urban transit has elevated equipment standards for both safety and performance. The industry's shift toward automation is driving intelligent grab crane development, promising broader applications beyond metro construction.