Efficiency Analysis of Liebherr Machines in High-Rise Building Demolition Processes

Abstract

This technical analysis presents the results of a comprehensive study on the efficiency of Liebherr demolition machines in the context of high-rise building demolition. The study was conducted based on data collected from 12 demolition projects carried out by the TREE Group between 2021 and 2023. The analysis focuses on operational parameters, fuel consumption, work efficiency, and the impact of operator techniques on the effectiveness of the entire demolition process.

1. Introduction

Demolition of high-rise buildings is one of the most demanding tasks in the demolition industry. It requires the use of specialized equipment that must meet rigorous safety, efficiency, and precision requirements. Liebherr machines, particularly the R 950 Demolition and R 960 Demolition models, are widely used in such projects.

The aim of the analysis was to determine the actual efficiency of these machines under operational conditions and to identify factors affecting their effectiveness. The results have practical applications in planning demolition projects, cost optimization, and operator training.

2. Research Methodology

2.1 Scope of Research

The analysis includes data collected from 12 demolition projects carried out by the TREE Group, in which a total of 8 Liebherr machines were used (4 R 950 Demolition models and 4 R 960 Demolition models). The projects were implemented in various urban conditions and with different types of building structures.

2.2 Data Collection

Data was collected using:

• Telemetry systems installed in machines
• Operator work logs
• Time measurements of individual demolition stages
• Cameras monitoring machine operation
• Fuel consumption measurements

2.3 Analyzed Parameters

The study considered the following parameters:

• Operational efficiency (m³ of demolished structure/hour)
• Fuel consumption (l/h and l/m³ of demolished structure)
• Work cycle times
• Impact of operator experience on efficiency
• Failures and technical downtime
• Impact of demolition techniques on overall efficiency

3. Analysis Results

3.1 Operational Efficiency

The average operational efficiency for the analyzed machines was 18.4 m³/h for the R 950 Demolition model and 23.6 m³/h for the R 960 Demolition model. Significant differences in efficiency were observed depending on:

• Building structure type (reinforced concrete, steel, mixed)
• Working height
• Operator experience
• Weather conditions

Machine Model	Average Efficiency (m³/h)	Min. Efficiency (m³/h)	Max. Efficiency (m³/h)
R 950 Demolition	18.4	12.2	25.7
R 960 Demolition	23.6	15.8	31.2

3.2 Fuel Consumption

Fuel consumption showed a strong correlation with work intensity and the type of structure being demolished. The average fuel consumption is as follows:

Machine Model	Average Consumption (l/h)	Consumption per Unit Volume (l/m³)
R 950 Demolition	38.2	2.08
R 960 Demolition	45.7	1.94

The analysis showed that despite higher absolute fuel consumption, the R 960 Demolition model achieves better fuel efficiency per unit volume of demolished structure.

3.3 Impact of Operator Experience

The study showed a significant impact of operator experience on machine efficiency. Operators with more than 5 years of experience achieved on average 27% higher efficiency compared to operators with less than 2 years of experience. The most important factors affecting efficiency differences are:

• Ability to select the optimal demolition technique
• Precision in controlling the demolition arm
• Effectiveness in managing machine power
• Ability to predict structural behavior during demolition

3.4 Failures and Technical Downtime

The average failure-free operation time for the tested machines was 285 hours for the R 950 Demolition model and 312 hours for the R 960 Demolition model. The most common causes of technical downtime were:

• Hydraulic system damage (42% of cases)
• Problems with demolition attachments (31% of cases)
• Electronic failures (18% of cases)
• Other (9% of cases)

4. Optimization of Demolition Techniques

Based on the conducted research, optimal demolition techniques for different types of structures were identified:

4.1 Reinforced Concrete Structures

For reinforced concrete structures, the most effective technique proved to be gradual demolition from the top using a hydraulic hammer in the first phase (to crush concrete) and hydraulic shears in the second phase (to cut reinforcement). This combination allowed achieving efficiency 18% higher compared to demolition using only a hydraulic hammer.

4.2 Steel Structures

For steel structures, the highest efficiency was achieved using steel cutting shears, with precise planning of cutting sequences to control the collapse of structural fragments. This technique reduced fuel consumption by about 15% compared to other methods.

4.3 Mixed Structures

For mixed structures, a protocol for sequential attachment changes was developed, minimizing the time needed to change tools. Precise planning of the demolition sequence of individual structural elements also proved to be a key factor.

5. Economic Analysis

The economic analysis showed that optimally selected machines and demolition techniques can bring savings of 15-22% of the total cost of a demolition project. Based on data from the analyzed projects, the average cost of demolishing 1 m³ of structure was:

• Using optimal techniques: 78.3 PLN/m³
• Using standard techniques: 95.8 PLN/m³

6. Conclusions and Recommendations

6.1 Conclusions

Based on the conducted analysis, the following conclusions were formulated:

1. Liebherr machines from the Demolition series show high efficiency in high-rise building demolition processes, especially the R 960 Demolition model.

2. Operator experience is a key factor affecting work efficiency, with efficiency differences reaching up to 27%.

3. Appropriately selected demolition techniques can bring savings of 15-22% of the total project cost.

4. Regular operator training and systematic machine maintenance can significantly increase efficiency and reduce the risk of failures.

6.2 Recommendations

Based on the conducted analysis, the following is recommended:

1. Introduction of systematic training for operators, focused on optimal demolition techniques.

2. Implementation of real-time machine efficiency monitoring systems.

3. Development of detailed demolition plans taking into account the specifics of the structure and selection of optimal attachments.

4. Implementation of a preventive machine maintenance program, particularly targeting hydraulic systems, which are the most common cause of failures.

5. Consideration of investing in newer machine models for projects requiring particularly high efficiency.

7. Bibliography

1. TREE Group internal data from demolition projects 2021-2023
2. Technical specifications of Liebherr R 950 Demolition and R 960 Demolition machines
3. Krause, J. (2021). "Efficiency in High-Rise Demolition Projects". Journal of Construction Engineering, vol. 45, pp. 128-142
4. Liebherr Group (2022). "Technical Handbook for Demolition Excavators"
5. Nowicki, M., Kowalski, T. (2022). "Comparative Analysis of Demolition Techniques in Urban Conditions". Engineering and Construction, no. 3, pp. 78-92

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The analysis was prepared by the Research and Development Department of the TREE Group based on data from actual demolition projects. The results have practical applications in planning and implementing demolition projects and in the process of training machine operators.