what is bar bending schedule BBS and advantages

what is bar bending schedule BBS and advantages

What is Bar Bending Schedule?
Bar bending is a process of cutting and bending reinforcement steel into shapes as suggested by the structural engineer for various structural elements like like Slab, Beam, Coloum, Footing etc.
Bar Bending Schedule is a list details of bent reinforcement bars used in any given structural concrete (RCC) element. The list contains bar mark, its diameter, length, shape and weight.
Bar bending schedule is used by site engineers/home owners to estimate the quantities of various diameters of bars used in a construction, perform bar bending at site, and check the reinforcement work done by the contractor.

Advantages of bar bending schedule in construction:
Provides better estimation of reinforcement steel to be used in each structural concrete member. Also you can compute the overall reinforcement required for the project.Helps you in procurement of materials and better stock management. Reinforcement Steel is the costliest material out of all building materials accounting for almost 25% of the project cost. It is not always advisable to purchase the whole steel lot in one go (for house construction projects of more than 2 Floors). Steel requirement has to be divided in phases based on the construction. Bar bending schedule makes it easy for ordering the exact quantities of steel required for a specific phase of construction work.Bar Bending Schedule provides exact estimate of the quantities required. So wastage at site can be avoided by careful monitoring of the contractor and using bar bending schedule along with that Using Bar Bending Schedule, reinforcement can be cut and bend at factory and can be directly transported to site. This will not only reduce the wastage of reinforcement steel at site but also will reduce on labor costs, thus helping in reducing the overall cost of the project Bar Bending Schedule helps site engineers and quality inspectors to check and approve the reinforcement thus aiding in better quality control Billing can be prepared real fast and easy using Bar bending schedule. It is also easy for clients to approve those bills for payment Bar bending schedule can help the team cut and bend the bars at a separate location while other activities are performed in parallel, thus saving time during construction

Tips for Preparing Bar Bending Schedule
Prepare bar bending schedule for different RCC elements separately (i.e., Divide the table into parts for Footing, Pedestal, Plinth Beam, Coloumn, Slab etc.)
Keep the unit weights of bars handy. This will help you in designing the Keep some thumb rules handy that will help you in double checking your calculation. Some of them are The total quantity of steel for a low rise building structure varies from 3-4 Kgs/sqft of build-up area Volume of steel reinforcement for slab is roughly 1.5-2% the volume of concrete (Volume of steel can be calculated by dividing the weight by density of steel i.e., 7850 kg/cum)

RCC member% Steel by volume of concrete
Slab 1.5-2%
Column 2.5-3%
Beam 2.5-3%

A positive rolling margin (weight higher than standard weight) shall fall short while placing at site.
Keep an eye on Positive rolling %, to save on steel cost.

Rolling margin allowance should be given prime importance at site while preparing the BBS. As mentioned earlier BBS gives us the cutting length of a bar but we procure steel by weight (as the standard weight by calculation varies from actual weight of bar due to rolling margin).Mentioning type of steel is also important sometimes. This depends on the project requirement. If more than one grade of bar is used. This helps procurement team in buying the right type of steel required