Demolition by Crane and Hammer Modified Excavator

[MikePhua]

Innovative Methods in Stack Demolition
Demolishing industrial smokestacks has always required a blend of brute force and precision. Traditionally, controlled explosives or high-reach excavators were the tools of choice. However, in certain cases—especially when working near active infrastructure or in confined urban zones—contractors have turned to more creative solutions. One such method involves suspending a modified excavator from a crane, allowing it to operate at elevation and chip away at the structure with a hydraulic hammer.
This approach is not only visually striking but also mechanically complex. It requires precise coordination between crane operators and excavator technicians, as well as a deep understanding of load dynamics, swing control, and hydraulic response under suspended conditions.
Terminology annotation:
- Hydraulic Hammer: A percussion tool mounted on an excavator, used to break concrete, rock, or masonry through repeated high-force impacts. - Modified Excavator: A machine altered from its standard configuration, often stripped of its undercarriage and reinforced for aerial operation. - Suspension Rigging: The system of cables, shackles, and spreader bars used to safely lift and stabilize heavy equipment during crane operations.
Engineering the Lift and Excavator Modifications
To suspend an excavator from a crane, the machine must be stripped of its tracks and counterweight to reduce mass and simplify rigging. The boom and stick are retained, along with the hydraulic hammer, which is powered either by onboard systems or external hydraulic packs. The cab is often reinforced or removed entirely, depending on whether remote control is used.
The crane must be rated for the full dynamic load, including the excavator’s weight, hammer recoil, and any debris impact. A spreader bar is typically used to distribute the lifting force and prevent cable pinch. Operators must account for:

• Excavator weight (typically 15–25 tons depending on model)
  
• Hammer impact force (up to 5,000 ft-lbs)
  
• Crane boom angle and radius
  
• Wind conditions and stack stability
  

One contractor in Ohio used a Liebherr LR 1300 crawler crane to suspend a modified Komatsu PC210 with a hammer attachment. The stack was 180 feet tall, and the demolition took place over five days, with the excavator chipping away in 10-foot increments. The project avoided the use of explosives due to nearby gas lines and achieved full removal with minimal disruption.
Safety Protocols and Operator Coordination
Suspended demolition requires rigorous safety planning. The excavator operator must be trained in aerial operation, often using remote control systems to avoid placing personnel in the cab. The crane operator must maintain constant communication, adjusting boom position and tension to match the excavator’s movements.
Terminology annotation:
- Remote Control Excavation: Operating an excavator via wireless controls, allowing the operator to stand at a safe distance. - Dynamic Load: The changing weight and force exerted by a moving object, critical in crane calculations. - Swing Control: The ability to stabilize lateral movement of suspended loads, often using tag lines or hydraulic dampers.
Safety measures include:

• Redundant rigging points and load-rated shackles
  
• Real-time load monitoring via crane telemetry
  
• Emergency stop protocols and evacuation plans
  
• Pre-demolition structural analysis of the stack
  

In one incident in Germany, a suspended excavator struck an unexpected steel reinforcement inside a stack, causing the hammer to recoil and swing the machine. The crane operator reacted quickly, stabilizing the load and preventing damage. The event led to revised inspection protocols and the use of ground-penetrating radar before future demolitions.
Historical Context and Equipment Evolution
The concept of using cranes to elevate demolition tools dates back to the 1970s, when wrecking balls were suspended from lattice booms to knock down masonry buildings. As hydraulic technology advanced, contractors began experimenting with suspended breakers and shears. The modified excavator method emerged in the 1990s, offering greater control and precision.
Manufacturers like Caterpillar, Komatsu, and Volvo have since supported custom rigging for demolition contractors, offering stripped-down excavator frames and remote control kits. While not officially endorsed for aerial use, these machines have proven adaptable when engineered correctly.
Lessons from the Field and Practical Advice
Operators considering suspended demolition should:

• Consult with structural engineers and crane specialists before rigging
  
• Use excavators with proven hydraulic reliability and hammer compatibility
  
• Reinforce boom and stick joints to handle elevated stress
  
• Maintain clear communication protocols between ground crew and crane cab
  
• Document all modifications for insurance and compliance purposes
  

One demolition foreman shared that his team used a modified CAT 320C suspended from a Manitowoc crawler crane to remove a 150-foot stack in a refinery. The job was completed in four days, with zero incidents and full client satisfaction. He emphasized the importance of pre-rigging rehearsals and having backup hydraulic packs on standby.
Conclusion
Demolishing a power plant stack with a crane-suspended excavator and hydraulic hammer is a testament to the ingenuity of modern contractors. It blends structural engineering, equipment modification, and operational choreography into a high-stakes ballet of steel and concrete. While not common, this method offers a viable alternative in sensitive environments where precision and control outweigh brute force. In the world of demolition, sometimes the most effective tool is one that hangs in the air, striking with purpose and guided by experience.