Crane Demolition of Prefabricated Panel Houses

A crane can be used to demolish prefabricated panel houses, but specific conditions must be met and standard operating procedures must be followed.

I. Feasibility Conditions for Crane Demolition of Prefabricated Panel Houses

Theoretically, a crane can be used to remove hollow floor slabs that are 3.6 meters high, as the arm span of a standard 25-ton crane can cover this height. However, the following conditions must be met:

1. Operating Radius Limitation: The crane's operating radius must be less than 8 meters to ensure the stability of the boom and lifting capacity.
2. Slab Weight Limitation: The weight of a single slab must not exceed 2 tons to avoid overloading, which could lead to equipment tipping or structural damage.
3. On-Site Space Requirements: There must be sufficient space to extend the crane's outriggers, ensuring the equipment is level and stable to prevent the risk of tipping.

II. Operating Procedures and Safety Precautions

1. Wire Rope Fixing Method:
   • The wire ropes must be symmetrically fixed at the center of gravity of the slab to prevent tilting or slipping due to an off-center load.
   • The fixing points should be selected where the slab structure is intact, avoiding cracks or damaged areas.
2. Slab Structure Inspection:
   • Before demolition, the slab should be scanned for cracks, and slabs with structural damage should be demolished in sections to prevent complete fracture.
3. Weather Considerations:
   • In rainy weather, wire ropes are prone to slipping, so anti-slip clamps should be added or the wire ropes should be wrapped with anti-slip materials to ensure friction.
4. Lifting Speed Control:
   • Lifting should be done at a constant speed to avoid sudden starts or stops that could cause the slab to swing. A warning zone should be established within 10 meters below to prohibit personnel entry.

III. Applicable Scenarios for Alternative Equipment

For small prefabricated panel buildings such as bungalows, the following equipment may be more efficient and cost-effective:

1. Spider Crane: Lightweight and capable of entering indoor spaces, suitable for narrow sites, with hourly costs 40% lower than those of a standard crane.
2. Forklift with Lifting Arm: Combines transportation and lifting functions, with lower costs, and can avoid damaging courtyard surfaces.
3. Electric Hoist: Used with a triangular bracket, it offers higher precision and is suitable for scenarios with strict requirements for demolition positions.

IV. Practical Application Cases

Law enforcement agencies have used cranes to demolish illegal prefabricated panel structures on riverways, such as removing containers occupying closed river channels. In such scenarios, the crane's position and operating radius must be adjusted according to the on-site environment (e.g., river width, surrounding obstacles) to ensure safe operation.