To know about the bar bending schedule we have to start from the beginning. Choosing a suitable material for construction is essential, and steel is often the material of choice. This is because steel is strong, durable, and cost-effective.
Steel is suitable for construction due to its ability to bend, resistance to corrosion and oxidation, and high tensile strength.
At the end of this blog, you’ll get an overview of the bar bending schedule.
What is Bar Bending Schedule?
A Bar Bending Schedule (BBS) is a tabular document that outlines the details of the reinforcement bars used in a reinforced cement concrete (RCC) structure.
It includes information such as the size and type of bars, the shape of the bends (with sketches), the number of bars in each set, the length of each bar, the total length in running meters, the weight per unit length, and the total weight of the bars.
The lengths and sizes of bars are determined using the Bar Bending Schedule during construction. This schedule assists in ensuring that the right materials are readily available.
Importance of Bar Bending Schedule
BBS is an essential process for classifying total steel bars in civil engineering construction. This tabular representation shows the length, thickness, diameter, and other properties of the reinforcement bars used. Bar bending schedules also contribute to low-cost house construction.
- The construction of Reinforced Cement Concrete (RCC) requires the use of a Bar Bending Schedule (BBS) to ensure its importance.
- BBS helps calculate the cutting length of bars and reconcile materials in reinforcement processing.
- BBS helps reduce wastage and saves time & money by enabling efficient work on concrete units during construction.
- Bar Bending Schedule (BBS) also helps in easy verification, inspection, and cross-checking of the work.
- It is also helpful for easy estimation and evaluation of costs incurred at the time of manufacturing.
- The warehouse reduces transportation costs by cutting and bending the steel.
How Does Bar Bending Schedule Work?
The bar bending schedule plays a pivotal role in construction. The working of the bar bending schedule is simple. The schedule dictates the usage of RCC bars.
BBS reduces waste in cutting, improves quality control, assists in stock management, speeds up auditing, and estimates steel quantity.
Things to Keep in Mind Before Bar Bending Schedule Calculation
- Group the bars together for each structural unit and each floor.
- List the bars numerically and include the length, size, shape, and type specifications in accordance with BS 8666.
- Each bar must have a unique label attached to the bundle of bars.
- Calculate the cutting length and bending length separately.
- Length of hook: 9D. Total length of straight bar w/ hooks at both ends: L + 18D.
- 45° cranked bar: additional length for 1 bent-up = 0.45D; 2 bent-ups = 0.9D.
- 30° cranked bar: 2D inclined, 1.73D horizontal, 0.3D extra per crank.
- The bending length for stirrups is 1D for 45°, 2D for 90°, and 3D for 135°.
- The overlap or lap length at the joint is equal to the regular length of the bar (usually 12m).
- The length of the bent-up bar for 30°, 45°, and 60° are 0.3D, 0.45D, and 0.6D respectively.
- Percentage of reinforcement for: lintel/slab = 0.7-1%, beams = 1-2%, columns = 1-5%, foundation raft/footing = 0.5-8%.
Bar Bending Schedule for Slab
There are different types of slabs in construction and BBS differs according to them. Here is how you can prepare Bar Bending Schedul for your slab.
- Start by gathering the necessary information, such as the slab dimensions, concrete cover requirements, and design drawings.
- Determine the size and spacing of the main reinforcement bars (also known as bottom bars) based on the design requirements and load calculations. Typically, these bars are placed at the bottom of the slab.
- Calculate the total length of each main reinforcement bar required for the slab by considering the dimensions and spacing. Round up the lengths to the nearest meter or as specified in the project specifications.
- Determine the size and spacing of the distribution reinforcement bars (also known as top bars) based on the design requirements. These bars are usually placed near the top surface of the slab to control cracking.
- Calculate the total length of each distribution reinforcement bar required for the slab, taking into account the dimensions and spacing. Round up the lengths as necessary.
- Decide on the bending shapes for the reinforcement bars, such as hooks, bends, or straight bars, depending on the design and structural requirements. Refer to the design drawings or specifications for specific details on bar shapes.
- Create a table or spreadsheet to document the bar bending schedule. Include columns for bar number, bar mark, bar description, length, shape, and any additional information required by the project.
- Fill in the table with the relevant information for each bar. Assign unique bar numbers and marks to identify each bar correctly. Provide a concise description of the bar, specifying its size and placement.
- Indicate the length of each bar, considering the rounded-up values calculated earlier. Ensure accurate measurements to avoid any discrepancies during construction.
- Specify the bending shapes for each bar, indicating the type and dimensions of bends, hooks, or any other required shapes. Include clear diagrams or illustrations if necessary.
- Review the bar bending schedule for accuracy, completeness, and compliance with the design requirements. Check for any clashes or conflicts with other structural elements.
- Present the finalized bar bending schedule to the relevant stakeholders, such as the structural engineer, contractor, or construction team, for approval and implementation.
Bar Bending Schedule for Beam
Bar Bending Schedule calculation for a beam is essential in constructing a concrete structure. Importantly, be aware of the beam design and the forces it will encounter, and use appropriate equations to determine the size, number, and length of the steel reinforcement bars required.
Provide a comprehensive overview of the entire beam-building process in the bar bending schedule for the beam, ensuring all necessary information is included. Critically consider the area of steel reinforcement, the number and size of bars, and their respective lengths to guarantee the correct amount and type of steel reinforcement is used. Proper calculation of these variables is essential for creating a safe and reliable beam.
Conclusion
In conclusion, a bar bending schedule is an essential tool for the construction industry, allowing for efficient and accurate planning, execution, and monitoring of reinforcing steel works.
Create a clear and detailed list of all required steel bars, including their lengths, shapes, and quantities, using the bar bending schedule to help ensure timely ordering and delivery of all necessary materials.
Additionally, it allows for identifying any potential errors or discrepancies in the design and construction process, allowing for prompt corrections and adjustments.
Overall, the use of a bar bending schedule is crucial for maintaining a high level of quality and safety in any construction project that involves reinforcing steelworks.
