All About BBS of footing and estimation of Steel quantity

All About BBS of footing and estimation of Steel quantity

BBS (Bar Bending Schedule) of footing and estimation of steel quantity is an essential process in the construction industry. It involves precise calculations and detailed planning to ensure the structural stability and durability of a building. In this article, we will delve into the world of BBS and explore the importance of proper steel quantity estimation in footings. From its definition and purpose to the step-by-step process, we will provide a comprehensive guide to understanding all aspects of BBS of footing and steel quantity estimation. So, whether you are a construction professional or simply curious about the technicalities of building design, read on to discover all you need to know about this crucial aspect of construction.

BBS of footing and estimation of Steel quantity

BBS of footing and estimation of Steel quantity

BBS, or bar bending schedule, is an important aspect of designing footings in civil engineering projects. It involves detailing the reinforcement steel required for constructing the footing as per the design specifications.

The BBS for a footing is a detailed document that includes information such as the dimensions of the footing, the type and size of reinforcement steel to be used, and the spacing and location of the steel bars. It is essential to accurately determine the BBS for a footing to ensure the proper strength and stability of the structure.

The first step in preparing the BBS for a footing is to calculate the quantity of steel required. This can be done by estimating the load that the footing will have to bear, as well as the soil bearing capacity. Based on these factors, the size and shape of the footing can be decided, and the reinforcement steel required can be calculated.

The BBS should include a detailed drawing showing the layout of the reinforcement steel in the footing. It should specify the size and number of bars, the length and location of bends and laps, and the spacing between bars. This information is crucial for the construction team to correctly place the steel bars in the footing as per the design.

One important aspect to consider while preparing the BBS is the cover to be provided to the reinforcement steel. Cover refers to the thickness of concrete covering the steel bar. It is essential to provide adequate cover to protect the steel from corrosion and to ensure proper bonding between the steel and concrete. The recommended cover for footing reinforcement is typically between 50-75mm.

The next step is to estimate the quantity of steel required for the footing based on the BBS. This involves calculating the total length of each type of reinforcement bar required and converting it into the weight of steel in kilograms. This calculated quantity helps in ordering the required amount of steel and keeping track of the material used during construction.

Another important aspect of estimating the steel quantity for a footing is to account for wastage. A certain amount of steel is typically wasted during bending, cutting, and fixing of the bars. It is recommended to account for a wastage factor of 2-5% while calculating the steel quantity.

In conclusion, preparing a detailed BBS for the footing is crucial in ensuring the structural stability and safety of the building. It helps in accurately determining the amount of reinforcement steel required and provides clear information for the construction team to follow. Estimating the steel quantity involves careful calculations and attention to detail, which ultimately contributes to the success of the project.

BBS ( bar bending schedule) of footing

BBS ( bar bending schedule) of footing

BBS (bar bending schedule) of footing is a detailed document that specifies the reinforcement details of a concrete footing. It is an essential tool for civil engineers to prepare the reinforcement drawing for footing construction.

The BBS of a footing includes information such as the type and size of reinforcement bars, their length, number of pieces, and their placement in the footing. This schedule is prepared based on the design drawings and calculations, which specify the necessary reinforcement to resist the load of the structure.

The first step in preparing the BBS of footing is to understand the design drawings and calculations. These documents provide information about the size and shape of the footing, the type of reinforcement to be used, and the load it needs to resist. Ensuring accuracy at this stage is crucial as any mistakes can result in significant structural failures.

Once the design is finalized, the engineer can proceed to prepare the BBS. The first section of the BBS includes all the general information such as project name, location, drawing number, and scale. Next, the details of each bar used in the footing are listed, such as its diameter, length, shape, and type of reinforcement.

The BBS also includes the spacing between the bars, which plays a crucial role in the overall strength and stability of the footing. The spacing is usually specified in terms of the distance between the center of two bars, and it should comply with the design requirements.

Another important aspect of the BBS is the lap length of the bars. The lap length is the minimum distance required to overlap two reinforcement bars to transfer the load from one bar to the other. This length is calculated based on the type of reinforcement, concrete strength, and load conditions.

In addition to the reinforcement bars, the BBS also includes details of stirrups, which are also essential for the stability of the footing. The BBS specifies the number, size, and arrangement of stirrups, which help to resist shear forces and prevent the longitudinal bars from buckling.

The BBS of footing also includes information about the cover, which is the distance between the reinforcement bars and the surface of the concrete. This cover is essential to protect the bars from corrosion and other environmental factors. The cover specified in the BBS should comply with the design requirements and local building codes.

In conclusion, the BBS of footing is an essential document in the construction of a concrete footing. It provides detailed information about the reinforcement, spacing, lap length, stirrups, and cover, which are crucial for the strength and stability of the footing. It ensures that the construction is carried out accurately according to the design and specifications, making it an important tool for civil engineers.

calculate cutting length of single piece of main bar for footing

calculate cutting length of single piece of main bar for footing

Cutting length refers to the length of steel bar that is needed for a specific structural element in a construction project. In this case, we will be discussing the calculation of cutting length for a single piece of main bar used in a footing.

A footing is an essential part of any structural foundation as it distributes the load of the building to the soil beneath. The main bar, also known as the longitudinal reinforcement bar, is the primary reinforcing steel used in footings to provide tensile strength and stability.

The process of calculating the cutting length of a single piece of main bar for a footing involves the following steps:

1. Determine the dimensions of the footing: The first step is to identify the dimensions of the footing, which includes the length, width, and thickness. These dimensions can be obtained from the structural drawings or by measuring the actual footing on-site.

2. Calculate the perimeter of the footing: Once the dimensions are known, the next step is to calculate the perimeter of the footing. This can be done by adding the length and width of the footing and multiplying it by two.

Perimeter = 2 x (Length + Width)

3. Determine the concrete cover: The concrete cover refers to the thickness of concrete that will cover the main bar. It is usually specified in the structural drawings and can range from 25mm to 50mm.

4. Determine the clear cover: The clear cover is the distance from the outer surface of the footing to the center of the main bar. It is typically 25mm to 50mm, depending on the size of the bar and the concrete strength.

5. Calculate the cutting length: The cutting length is calculated by subtracting the concrete cover and clear cover from the perimeter of the footing.

Cutting length = Perimeter – (Concrete cover + Clear cover)

6. Add the bend allowance: Main bars are usually bent at the ends to provide anchorage. The length of the bend allowance depends on the diameter of the bar and is usually specified in the structural drawings. The length of the bend allowance should be added to the cutting length obtained in the previous step.

7. Add the lap length: In the case of footings, the main bar is usually lapped with another bar to provide continuity. The lap length is typically 40 times the diameter of the bar, and it should be added to the cutting length obtained in step 6.

8. Deduct the bar overlap: In some cases, the main bar may overlap with the starter bar or the top reinforcement bars of the foundation. In such situations, the overlap length should be deducted from the cutting length obtained in the previous step.

9. Trim the extra length: The final step is to trim the extra length based on the standard bar length available in the market. This ensures that the bar can be easily transported and handled on-site.

In conclusion, calculating the cutting length of a single piece of main bar for footing is a straightforward process that involves identifying the dimensions, calculating the perimeter, determining the concrete and clear cover, and making necessary adjustments for bend allowance, lap length, and bar overlap. Accurate calculation of cutting length is vital for the proper execution of the footing, ensuring the structural stability and longevity of the building.

calculate total cutting length of main bar in footing

calculate total cutting length of main bar in footing

In the construction of a building, one of the important elements is the footing. The footing is the base of the foundation that distributes the load of the building to the ground. In order to ensure the strength and stability of the footing, it is important to carefully calculate the total cutting length of the main bar.

The main bar is the reinforcement bar that is placed in the bottom of the footing, along the length and width of the structure. It is responsible for bearing the vertical load of the structure and transferring it to the ground. The total cutting length of the main bar is the total length of the bar required for the footing, taking into consideration the length of the reinforcement bar needed for the lap joints and development length.

The calculation of the total cutting length of the main bar in a footing involves several steps:

1. Determine the dimensions of the footing: The first step is to determine the dimensions of the footing, which includes the length, width, and depth of the footing. This information can be obtained from the structural drawings.

2. Calculate the total perimeter of the footing: The perimeter of the footing is the sum of all its sides. It can be calculated by adding the length and width of the footing and multiplying it by two.

3. Determine the cover for the main bar: The cover is the distance between the outer surface of the footing and the reinforcement bar. It is usually specified in the project drawings and varies depending on the type of structure and the environmental conditions.

4. Calculate the length of the lap joint: In order to ensure the continuity of the reinforcement, it is required to have lap joints where two bars are overlapped. The length of the lap joint is usually specified in the project drawings and is typically at least 40 times the diameter of the bar.

5. Determine the development length: The development length is the length of the reinforcement bar required to be embedded into the concrete to develop its full strength. It is calculated based on the diameter of the bar, grade of the concrete, and the bond strength between the concrete and the steel.

6. Calculate the total cutting length: By adding the perimeter of the footing, the thickness of the cover, and the lengths of the lap joint and development length, we can calculate the total cutting length of the main bar.

It is important to ensure that the calculated total cutting length is at least equal to or more than the actual length required for the footing in order to provide adequate reinforcement and ensure the strength and stability of the structure.

In conclusion, the calculation of the total cutting length of the main bar in a footing is an essential step in the construction process. It helps in determining the amount of reinforcement needed and ensures that the structure can withstand the applied load and last for a long time.

weight calculation of main bar in footing

weight calculation of main bar in footing

The weight calculation of the main bar in a footing is an important part of the structural design process. It helps to determine the amount of reinforcement needed to ensure the stability and strength of the footing. As a civil engineer, it is crucial to understand and perform accurate weight calculations for the main bar in footing to ensure that the structure can withstand the required loads.

The main bar in a footing is a longitudinal reinforcement that runs along the length of the footing to resist tension forces. It is usually placed at the bottom of the footing and runs parallel to the direction of the applied loads. The weight of the main bar is an essential parameter in determining the overall weight of the footing and its bearing capacity.

To calculate the weight of the main bar, the following steps can be followed:

1. Determine the Design Load: The first step is to determine the design load that the footing will need to resist. This includes the self-weight of the footing, along with the weight of the applied loads, such as the weight of the structure and any expected live loads.

2. Determine the Length of the Main Bar: The length of the main bar is equal to the length of the footing. This can be calculated by considering the length of the structure and the desired distance between the footings.

3. Calculate the Cross-Sectional Area of the Main Bar: The cross-sectional area of the main bar is usually specified in the structural drawings. However, if it is not provided, it can be calculated by multiplying the width of the bar by its depth. The width of the bar is usually given in millimeters (mm), while the depth is given in terms of the diameter of the bar (e.g., 16 mm).

4. Determine the Unit Weight of Steel: The unit weight of steel varies based on the type and grade of steel used. It is typically expressed in kilograms per cubic meter (kg/m3). The unit weight of steel can be obtained from reference books or can be provided by the steel manufacturer.

5. Calculate the Weight of the Main Bar: Once the above parameters have been determined, the weight of the main bar can be calculated by using the formula:

Weight of Main Bar = Length of Main Bar x Cross-Sectional Area of Main Bar x Unit Weight of Steel

The weight of the main bar is usually expressed in kilograms (kg).

Performing accurate weight calculations of the main bar in footing is crucial for ensuring the overall stability and strength of the structure. Any errors or miscalculations can lead to an overstressed footing, which can result in structural failure. Therefore, as a civil engineer, it is important to carefully follow the above steps and use accurate parameters to determine the weight of the main bar in a footing.

calculate cutting length of single piece of distribution bar in footing

calculate cutting length of single piece of distribution bar in footing

The distribution bar, also known as the steel reinforcement bar or rebar, plays a crucial role in the structural stability of a footing. It helps distribute the weight of the structure evenly on the foundation and resists cracking or bending under heavy load or external forces. As a civil engineer, it is essential to calculate the cutting length of the distribution bar with precision to ensure the structural integrity of the footing. In this article, we will discuss the steps to determine the cutting length of a single piece of distribution bar in a footing.

Step 1: Determine the Size and Number of Distribution Bars
The first step in calculating the cutting length of the distribution bar is to determine the size and number of bars required in the footing. This information can be obtained from the structural drawings and calculations. The distribution bars typically have a standard diameter ranging from 6mm to 50mm, and the number of bars is based on the load-bearing capacity of the footing.

Step 2: Calculate the Length of Footing
The length of the footing can be obtained by measuring the distance between the ends of the footing. This measurement should be taken at the bottom of the footing, at the top of the formwork, or at the top of the ground level, depending on the design and structural requirements.

Step 3: Determine the Development Length
The development length is the minimum amount of length that is required for the rebar to be embedded into the concrete to ensure proper bonding and transfer of load. This length can be calculated using the formula Ld = (ϕ x fy x d)/4τ_b, where Ld is the development length, ϕ is the diameter of the bar, fy is the yield strength of the steel, d is the depth of the footing, and τ_b is the bond strength.

Step 4: Calculate the Hook Length
The hook length is the additional length required at the end of the bar to ensure a smooth transition of the load from the bar to the concrete. This length can vary depending on the size and grade of the bar and is typically provided in the design drawings.

Step 5: Determine the Cutting Length of the Bar
The cutting length of the bar can now be calculated using the formula L = Length of footing -Development length at one end – Development length at the other end + 2 x Hook length.

Step 6: Add the Required Overlap Length
To ensure proper bonding and continuity of the reinforcement bars, it is essential to provide an overlap of at least 50 times the diameter of the bar. Add this overlap length to the calculated cutting length to determine the final length of the distribution bar.

In conclusion, as a civil engineer, it is crucial to accurately calculate the cutting length of the distribution bar to ensure the structural stability and safety of the footing. Proper calculation and placement of reinforcement bars is necessary to withstand the loads and forces acting on the structure and meet the required design standards and codes.

calculate total cutting length of distribution bar in footing

calculate total cutting length of distribution bar in footing

In the construction of a footing, distribution bars are used to distribute the load from the superstructure to the soil below. These bars are typically placed in the middle third of the footing and run in both directions. The total cutting length of distribution bars is an important factor in the design and construction of the footing, as it ensures that the bars are placed at the correct length and in the correct location to properly distribute the load.

To calculate the total cutting length of distribution bars in a footing, the following steps can be followed:

1. Determine the dimensions of the footing: The first step is to determine the size and shape of the footing. This includes the length, width, and thickness of the footing.

2. Find the clear cover: The clear cover is the distance between the outer surface of the concrete and the nearest surface of the reinforcement. The cover for footings is usually about 50mm to 75mm.

3. Calculate the effective depth: The effective depth is the distance between the top of the footing and the center of the distribution bars. It is equal to the thickness of the footing minus the clear cover.

4. Determine the spacing of the distribution bars: The spacing of the bars is usually specified in the design drawings and can vary depending on the type of footing and the load it is expected to support.

5. Calculate the total length of distribution bars in one direction: To determine the total length of bars in one direction, we need to multiply the spacing by the number of bars. For example, if the spacing is 150mm and there are 5 bars, then the total length of bars in one direction would be 750mm.

6. Determine the development length: The development length is the minimum length of reinforcement required to transfer the stress between the reinforcement and the concrete. It is usually specified in the design drawings and varies depending on the diameter of the bar and the type of reinforcement used.

7. Find the total cutting length: The total cutting length is the sum of the length of the bars in one direction plus the development length. This gives us the total length of the bars that need to be cut for one layer of reinforcement.

8. Multiply by the number of layers: The footing usually consists of multiple layers of reinforcement. To determine the total cutting length for all layers, we need to multiply the length of bars for one layer by the number of layers.

9. Add the end laps: If the bars are not long enough to cover the entire length of the footing, then end laps must be used. The length of the lap depends on the diameter of the bar and is usually specified in the design drawings. The total cutting length needs to be increased by the length of the end laps.

By following these steps, the total cutting length of distribution bars in a footing can be accurately calculated. This ensures that the bars are long enough and properly placed to effectively distribute the load and provide structural stability. It is important to refer to the design drawings and specifications to determine the exact calculation method and values for the specific footing being constructed.

weight calculation of distribution bar in footing

weight calculation of distribution bar in footing

The weight calculation of distribution bar in footing is an important aspect in the design and construction of a building’s foundation. Distribution bars, also known as reinforcing bars or rebar, are used to provide tensile strength to concrete structures. In footings, distribution bars are placed horizontally and vertically to distribute the loads from the superstructure evenly to the ground.

The weight calculation of distribution bar in footing is based on several factors such as the load on the structure, size of the footing, spacing of the bars, and the type of reinforcement used. In general, the weight of distribution bars is determined by using the total length of bars, which is calculated by multiplying the bar spacing with the total width and length of the footing.

The load on the structure is the primary factor in determining the weight of distribution bars. This load includes the dead load, which is the weight of the structure itself, and the live load, which is the weight of the occupants and the contents of the building. The magnitude of this load is determined by the design of the building and the type of structure, such as residential, commercial, or industrial.

The size of the footing also plays a crucial role in the weight calculation of distribution bars. The size of the footing is determined by the type of soil, the depth of the foundation, and the expected load on the structure. A larger footing will require more distribution bars to distribute the load evenly, thus increasing the weight of the bars.

The spacing of distribution bars is also a crucial factor in weight calculation. The spacing is measured from the center of one bar to the center of the adjacent bar. The standard spacing for distribution bars is typically 100-150 mm for horizontal bars and 150-200 mm for vertical bars. A closer spacing will require more bars, resulting in a higher weight of the distribution bars.

The type of reinforcement used also affects the weight calculation of distribution bars. The most commonly used reinforcement for footings is steel bars, which are available in various grades and sizes. The weight of the bars is determined by their cross-sectional area, which is dependent on the grade and size of the bars.

In conclusion, the weight calculation of distribution bar in footing is a critical aspect in the design and construction of a building’s foundation. It is essential to consider all the factors mentioned above to ensure that the weight of the bars is sufficient to withstand the loads on the structure. Proper weight calculation and placement of distribution bars will ensure a strong and stable foundation for the building.

calculate total requirement of reinforcement (steel) for the BBS of footing

calculate total requirement of reinforcement (steel) for the BBS of footing

The reinforcement or steel bars used in footing play a crucial role in providing strength, stability, and durability to the structure. Therefore, it is essential to calculate the total requirement of reinforcement accurately before implementing the BBS (Bar Bending Schedule).

The following are the steps to calculate the total requirement of reinforcing steel for footing:

1. Understanding the Structural Design: The first step in calculating the reinforcement requirement is to understand the structural design and the load-bearing capacity of the footings. This information can be obtained from the structural drawings and design calculations provided by the structural engineer.

2. Determine the Type of Footing: There are different types of footing, such as isolated, combined, strip, and raft footing. The type of footing affects the reinforcement requirement, as it depends on the load capacity and soil conditions.

3. Calculate the Load on Footing: The load on the footing is determined by the total dead load (weight of the structure) and the live load (weight of the occupants and other temporary loads).

4. Calculate the Safe Bearing Capacity (SBC) of the Soil: The SBC of the soil is the maximum load that can be safely supported by the soil without causing any settlement or failure. This value can be obtained from the soil test report.

5. Determine the Size of Footing: Based on the load and the SBC of the soil, the size of the footing is calculated. This is an iterative process, and the size of the footing is finalized after checking the stability and bearing capacity of the soil.

6. Calculate the Bending Moment: The bending moment is the force that causes the footing to bend under the applied load. It is calculated by multiplying the load on the footing by the distance between the column and the edge of the footing.

7. Determine the Reinforcement Steel Grade: Based on the structural design, the type of footing, and the bending moment, the grade of the reinforcement steel is determined. The most commonly used grade of steel for footings is Fe415 and Fe500.

8. Calculate the Required Area of Steel: The required area of steel is calculated by dividing the bending moment by the product of the allowable stress and the effective depth of the footing. The effective depth is the distance between the top surface of the footing and the reinforcement steel.

9. Finalize the Reinforcement Bar Diameter and Spacing: Based on the required area of steel, the diameter and spacing of the reinforcement bars are finalized. The bars are placed in both the longitudinal and transverse direction of the footing, and the spacing should be such that it provides adequate cover to the bars.

10. Prepare the BBS: Once the reinforcement bar diameter and spacing are finalized, the BBS is prepared, which includes the details of each reinforcement bar such as diameter, length, shape, and spacing.

In conclusion, the total requirement of reinforcement for the BBS of footing is calculated based on the structural design, load on the footing, soil conditions, bending moment, and steel grade. By following these steps, the BBS can be accurately prepared, ensuring the strength and stability of the footing.

Conclusion

In conclusion, having a proper understanding of BBS and estimation of steel quantity is crucial for any construction project. By following the guidelines and techniques discussed in this article, engineers and contractors can ensure a strong and durable footing for their structures while also minimizing wastage of materials and reducing costs. BBS and estimation of steel quantity require meticulous planning and attention to detail, but the rewards are significant in terms of the structural integrity and longevity of the building. It is important to constantly review and update BBS and steel quantity estimations throughout the construction process to ensure the project stays on track and meets all safety and structural requirements. With proper implementation of BBS and accurate estimation of steel quantity, construction projects can be completed successfully, leading to safe and long-lasting


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