Preparing a rate analysis for Reinforced Concrete (RCC) work involves two main steps. The first step is to estimate the quantity of labour, materials, equipment, and miscellaneous items required for a specific quantity of reinforced concrete. The second step involves determining the component of the structure for which the RCC rate analysis is required, as the quantity of reinforcement steel required varies with slabs, beams, columns, foundation, RCC roads, etc.
It’s important to note that the quantity of other materials like sand, coarse aggregate, and cement remains the same for the same mix design (mix proportion) of concrete. However, the quantity of reinforcement steel required varies with the type of structural component being worked on. Consequently, labour rates for reinforcement work also vary with the type of structural component being worked on since the quantity of reinforcement steel required will be different.
The quantity of materials like sand, cement, and coarse aggregates also varies with the mix design. For example, M15 (1:2:4), M20 (1:1.5:3), M25, M30, etc., will all require different quantities of these materials. Therefore, it’s important to take the mix design into consideration when estimating the required quantity of materials for the RCC work.
The following passage discusses the rate analysis for one cubic meter of reinforced concrete.
No further information or context is provided, so no additional content can be added.
Data required for RCC Rate Analysis:
1. Estimation of materials:
In order to estimate the materials required for a particular concrete mix design, we need to take into account several factors. These materials typically include sand, cement, coarse aggregate, and steel. For the purposes of this exercise, we will be using a mix design of 1:1.5:3.
One important consideration when estimating materials is the difference between wet and dry volume. When materials such as sand and aggregates are in their dry state, they contain voids that can affect the overall volume of the finished product. As a result, we need to take into account the fact that the dry volume of materials required is typically 1.54 times greater than the wet volume of concrete.
Using this calculation, we can determine the total volume of materials required for 1 m3 of wet concrete. For our specific mix design, we will need to account for a total volume of 1.54 m3 of materials in order to ensure that we have enough to complete the project. By taking these factors into consideration, we can accurately estimate the materials required for a given mix design and ensure that we have everything we need to get the job done.
a) Bags of cement required:
To calculate the volume of cement needed for a concrete mix, it is important to know the volume of the overall mix. Typically, concrete is measured in cubic meters, and so the volume of cement required will also be calculated in cubic meters. This means that for every 1 cubic meter of concrete, a certain amount of cement will be required. The exact amount of cement needed will depend on the specific mix design being used, as well as the desired strength and other factors. However, it is generally accepted that the volume of cement required for 1 cubic meter of concrete can be determined through a formula or calculation based on the specific mix being used. This information is important for anyone involved in the construction or engineering industry, as it ensures that the proper amount of materials are being used for a given project.
The given context mentions the volume of a certain space, which is equal to 0.28 m3. The context also provides information about the volume of one bag of cement, which is equal to 0.0347 m3.
Based on this information, we can calculate the number of bags of cement required to fill the given space. To do this, we can divide the volume of the space by the volume of one bag of cement.
So, the number of bags of cement required can be calculated as follows:
Number of bags of cement = Volume of space / Volume of one bag of cement
Substituting the given values in the above formula, we get:
Number of bags of cement = 0.28 m3 / 0.0347 m3
Simplifying this expression, we get:
Number of bags of cement = 8.07
Therefore, the number of bags of cement required to fill the given space is 8.07.
The given context describes the quantity of cement and sand required for a construction project. Specifically, it states that 8.07 bags of cement are needed for the project. In addition to this, the context also mentions the volume of sand required for the project, but the specific calculation for this quantity is not provided.
= 0.42 m3 of sand.
c) Volume of Coarse Aggregate Required
Volume of Coarse Aggregate =
= 0.84 m3 of coarse aggregates.
d) Estimation of Reinforced Steel:
To determine the amount of steel required for a structure, there are two methods that can be used. The first method involves having access to the structure’s drawing, which allows for the calculation of the total weight of steel required. This weight can then be divided by the total volume of concrete used for each component of the structure, such as slabs, beams, columns, foundations, and roads. By doing this, the weight of reinforcement steel per cubic meter of concrete can be determined.
The second method involves assuming the percentage of reinforcement required for each component of the structure. For example, for RCC columns, it is generally assumed that 2.5% of the concrete volume will require reinforcement steel. This percentage can vary depending on the specific structure and past experiences with similar structures.
Overall, by using these methods, the amount of steel required for different components of the structure can be estimated. For instance, if we consider the example of an RCC column where 2.5% of the concrete volume requires reinforcement steel, the weight of steel required can be calculated accordingly.
=196.25 kg.
2. Labour Requirement for 1m3 of RCC:
The labours required for a concrete project are typically presented in terms of the number of days each particular labour needs to complete their work for a given quantity of concrete.
There are several types of labours that may be required for a concrete project. Firstly, a mason is typically needed and it has been determined through Standard Schedule of Rates and Analysis of Rates that one mason is required for 0.37 days.
Secondly, unskilled labourers are required, and one unskilled labourer is needed for 3.5 days to complete their work for the given quantity of concrete.
Thirdly, a water carrier is needed to supply water for the project. It has been determined that one water carrier is required for 1.39 days.
Fourthly, the requirement for bar benders depends on the weight of reinforcement. For the purpose of this project, it has been assumed that one bar bender is required for 100 kg of steel for one day.
Finally, for operating the concrete mixer and vibrator, one operator each is required. It has been determined that one mixer operator and one vibrator operator are needed for 0.0714 days each.
3. Equipments and sundries:
The context provided suggests that certain charges, such as equipment and water charges, miscellaneous items, and tools and tackles, can be estimated as a percentage of the total cost of materials and labor. Specifically, the given percentage is 7.5%.
This implies that when estimating the total cost of a project, it may be helpful to factor in these additional charges as a percentage of the cost of materials and labor. By doing so, one can ensure that all potential expenses are accounted for and that the project budget is accurate.
It is important to note, however, that the percentage provided is merely an assumption and may not apply to all projects or situations. Factors such as the nature of the project, location, and other variables may affect the actual percentage of these charges.
Therefore, while assuming a percentage for equipment and other charges may provide a useful guideline, it is always advisable to conduct a thorough analysis of the project requirements and expenses to arrive at an accurate estimate.
4. Contractor’s Profit:
The profit earned by a contractor can vary depending on several factors such as location, organization, and type of work. Typically, it falls between 10% to 20% of the total cost of materials, labor, and equipment used for a project. In our case, let’s consider it to be 15%. We have already determined the quantity of each item required in the previous three steps. To perform a rate analysis of Reinforced Cement Concrete (RCC), we need to multiply the quantity of each item with its corresponding rate to calculate the cost of every element of work. However, rates can vary based on the location and time of the project. To simplify the process, it is recommended to use local or standard rates for the area. The sum of all the costs for the four items mentioned earlier will provide the rate or cost for 1m3 of concrete.