Earth excavation rate analysis is a process that determines the necessary labor and equipment for excavating a site. It does not involve any material analysis, unlike other rate analysis works. The excavation process can be done either manually or with the use of machines, or a combination of both, depending on the type and complexity of the excavation.
The excavation method used for earth excavation depends on various factors. The process can involve manual labor, where workers use shovels, picks, and other hand tools to excavate the earth. Alternatively, machines can be used to excavate the earth. The type of machinery used will depend on the size of the excavation and the soil conditions.
Rate analysis for manual excavation involves determining the number of workers required for the job, the number of work hours needed, and the cost of labor. Additionally, the equipment required for manual excavation, such as shovels and picks, will also be factored into the cost analysis.
For machine excavation, rate analysis involves determining the cost of operating the machinery, including fuel costs and maintenance expenses. The number of machine operators required for the job and their wages will also be included in the cost analysis.
In conclusion, rate analysis for earth excavation is an important process that helps to determine the cost of labor and equipment required for excavation. The excavation method used, whether manual or machine excavation, will depend on the size and complexity of the excavation, as well as the soil conditions.
Features of Rate Analysis of Earthwork Excavation
The rate of excavation is determined by several factors such as the depth of excavation, the type of soil, the method of excavation, and the distance required to dispose of the excavated soil. The cost for each of these factors is calculated and then added together to obtain the total cost for excavating a unit volume.
In addition to these factors, the labor productivity and labor output constant of a region or country are also important considerations in determining the rate of excavation. The area codes of a particular region or country are associated with specific labor output constants, which provide the coefficient value for the number of days required by a particular type of labor to excavate a 1-meter cube volume of soil for building work.
For instance, IS 7272-1974 is a standard that provides labor output constants for building work in various country zones. These constants are used to determine the time required by a specific type of labor to carry out excavation work, which helps to estimate the cost of the excavation project. By considering all these factors, it is possible to accurately determine the rate of excavation and the cost involved in completing the project.
Rate Analysis of Manual Earthwork Excavation
The given context describes a scenario where a work is required to excavate a pit of specific dimensions. The pit has a breadth of 2000mm, a length of 4000mm, and a depth of 1000mm. The concept that needs to be explained is related to rate analysis, which involves certain steps.
To understand rate analysis, it is important to break down the process into individual steps. In this case, the first step would be to determine the quantity of work required to excavate the pit. This would involve calculating the volume of the pit based on its dimensions. Once the volume has been determined, the next step would be to identify the rate at which the work can be completed.
To calculate the rate, it would be necessary to consider various factors such as the type of soil, the equipment required, the skill level of the workers, and the time required to complete the work. Based on these factors, a suitable rate can be determined. The rate would typically be expressed in terms of a unit of work, such as cubic meters of soil excavated per hour.
Once the quantity and rate have been determined, the next step in rate analysis would be to calculate the total cost of the work. This would involve multiplying the quantity of work by the rate, and then adding any additional costs such as labor, equipment rental, and transportation.
In summary, rate analysis is a process that involves determining the quantity of work required, identifying a suitable rate for completing the work, and calculating the total cost of the project. This process can be applied to a wide range of construction and excavation projects, and can help ensure that projects are completed efficiently and cost-effectively.
Step 1: Investigate Site and Determine the tasks
To conduct safe excavation, it is important to determine the type of soil present at the site and the associated tasks required. This can help in identifying any potential hazards and selecting appropriate safety measures. In some cases, shoring or dewatering may be necessary to ensure the stability of the excavation.
If the soil is found to have hard strata beneath, it may be necessary to use blasting techniques to excavate safely. It is also important to consider the provision of adequate working space and safety features at the site.
Listing out the required tasks can be helpful in estimating the amount of labor and equipment needed for the excavation project. By doing so, potential challenges can be anticipated and addressed, ultimately ensuring a safe and efficient excavation process.
Step 2: Determine the Volume of Excavation (m3)
In the given context, it is mentioned that while excavating a pit, a minimum working space of approximately 150mm is provided beyond the required dimension of the pit. The final dimensions of the pit are mentioned to be a breadth of 2000mm, a length of 4000mm, and a depth of 1000mm.
To calculate the volume of excavation, the formula for the volume of a rectangular prism is used, which is the product of its length, breadth, and height. By substituting the given values in the formula, the volume of excavation is calculated to be 8 cubic meters, which is then converted into cubic meters by dividing it by 1000.
Overall, the given context provides information about the necessary dimensions of a pit and the calculation of its excavation volume.
Step 2: Determine the Labour time Required for 1m3 Excavation
As per IS 7272-1974, for North Zones of India,
According to the given figure, the time required for a mate to perform 1 cubic meter (m3) of excavation in hard dense soil is 0.06 days, whereas for a mazdoor, it is 0.62 days per m3. If the excavation required is ‘V’ = 8m3, then the number of mates required would be 0.06V, which is 0.06 multiplied by 8, resulting in 0.48 mates. On the other hand, the number of mazdoors required would be 0.62V, which is 0.62 multiplied by 8, resulting in 4.96 mazdoors. This implies that to complete the excavation of the given depth in one day, approximately one mate and five mazdoors are required.
Step 3: Determine the cost of Mate and Mazdoor for Excavation
In construction projects, the cost of labor and machinery is determined based on a Schedule of Rates (SOR). This schedule can be obtained from various sources such as the Public Works Department (PWD), public sectors, or market trends specific to a particular region. The rate of labor can be scheduled either as a rate per square foot or as a rate of unskilled labor per day. For instance, the cost of labor for a mate is Rs. 370 per day, while the cost of labor for a mazdoor is Rs. 280 per day. To calculate the total labor cost, we multiply the number of mates by the cost per mate, and the number of mazdoors by the cost per mazdoor. In this case, the cost of one mate is Rs. 370, and the cost of five mazdoors is Rs. 1400. Thus, the total cost of labor is the sum of the cost of mate and the cost of mazdoor, which is equal to Rs. 1770.
Step 3: Determine the Cost of Tools & Equipment for Manual Earth Excavation
In the given context, it is mentioned that the cost of tools and equipment can be calculated as a percentage of labor costs. Specifically, it is assumed that 5% of the labor cost can be considered as the cost of tools and equipment.
To apply this formula to a practical scenario, the cost of tools and equipment required for an 8m3 Earth Excavation is calculated. It amounts to 5% of the labor cost, which is equal to Rs. 88.5.
Finally, the basic cost of excavation for the aforementioned Earth Excavation can be determined by adding the labor cost (Rs. 1770) and the cost of equipment (Rs. 88.5). The resulting sum is Rs. 1858.5.
Step 4: Determine the Overhead Cost and Profit
In the given context, it is mentioned that the overhead cost and profit for the excavation project is equal to 20% of the basic cost. The basic cost of excavation is not explicitly stated, but it can be assumed that it is 100% or the starting point of the calculation.
To determine the overhead cost and profit, 20% of the basic cost is multiplied by a value of 1858.5, which gives a result of Rs. 371.7. This means that the overhead cost and profit component of the excavation project is equal to Rs. 371.7.
To determine the total cost including overhead and profit, the basic cost of excavation, which is not explicitly stated, is added to the overhead cost and profit of Rs. 371.7. This gives a final total cost of Rs. 2230.2 for the excavation project, inclusive of overhead cost and profit.
Rate Analysis of Machine-based Earthwork Excavation
In this scenario, we are dealing with the excavation of soft soil up to a depth of 1.5 meters and a lead distance of 50 meters for every 10 cubic meters of concrete. The efficiency of the hydraulic excavator, tractor/dumper, and unskilled laborers is determined by their daily capacity, based on 8 hours of work.
The main objective of this excavation is to prepare the ground for the construction of a structure, which requires a certain amount of concrete to be laid. In order to achieve this, we need to excavate the soil to a certain depth and transport it to a designated location.
The softness of the soil presents a challenge that must be addressed by using appropriate machinery and personnel. The hydraulic excavator is a key component in this process, as it is capable of digging through the soil with ease. The tractor/dumper is also important for transporting the excavated soil to the required location.
Lastly, unskilled laborers are needed to assist in the excavation and transportation process. Their efficiency is also determined by their capacity, based on 8 hours of work. Overall, the success of this excavation project relies heavily on the efficiency of the machinery and personnel involved.
| Items | Units | Qty. | Rate | Amount |
| Hydraulic Excavator | Day | 0.04125 | 5000 | 206.25 |
| Tractor/Dumper | Day | 0.04125 | 1500 | 61.88 |
| Unskilled Labor | Day | 1.20 | 311.2 | 373.44 |
| Total | 641.57 | |||
| Water charges @1% total | 6.42 | |||
| Contractor Profit @15% | 96.23 | |||
| SUM | 744.22 | |||
| Gross Amt./CUM up to 1.5m depth | COST | 74.42 |
Capacity of the Equipment
According to the table provided, it takes a hydraulic excavator 0.04125 days to perform an excavation of 10 cubic meters. Based on this information, it can be determined that the excavator has a capacity of 242.24 cubic meters per day. This means that in a single day, the hydraulic excavator is capable of excavating up to 242.4242 cubic meters of soil.
Cost of Equipment
To calculate the cost of excavation, various factors such as the cost of equipment, labor, and contractor’s profit are taken into consideration. The cost of a hydraulic excavator for a day, including driver and fuel, is Rs. 5000, based on Table-2. Using this information, we can determine that 10m3 of excavation can be completed in 0.04125 days, and the cost of the hydraulic excavator for this amount of work would be Rs. 206.25.
Similarly, the cost of other equipment and laborers is calculated based on their capacity and the required number of days for excavation work. The coefficient per m3 or per 10m3 is used to calculate the cost of each equipment and laborer. After calculating the individual costs, the contractor’s profit is added to the total cost to determine the final cost of excavation.
By considering all these factors, the rate of excavation per 10m3 of soil excavation can be determined. It is important to note that different mechanical equipment has varying capacities per day for excavation work, and this information should be taken into account when calculating their cost.
Frequently Asked Questions
How do you perform rate analysis for earth excavation?
Excavation costs vary depending on several factors, including the depth of excavation, type of soil, method of excavation, and distance to dispose of the excavated soil. To determine the excavation rate, the costs of all these factors are added up for a unit volume of excavation.
In different regions or countries, area codes are used to establish a standard rate of labor productivity and a labor output constant. For instance, IS 7272 -1974 provides labor output constants for building work in different zones of a country. This code contains coefficient values that represent the number of days required by a particular type of labor to conduct excavation on a 1-meter cube volume.
What is the rate analysis for excavation?
Earth excavation rate analysis determines the necessary labor and equipment for excavating a particular site. This type of analysis does not involve material analysis unlike other rate analysis works. The excavation process may involve manual labor or the use of machines, or a combination of both methods. The method of excavation employed depends on the complexity and type of excavation required.