The Structure of a building is in Reinforced Cement Concrete.
The steel bars provided in the concrete make it strong to carry the tensile forces.
Thses bars are called as REINFORCEMENT.
The detailing of these bars [ Diameter ,spacing,covers, laps , dowel lengths, development lengths and shapes } are provided by RCC designer and are specified in the RCC drawing.
The extract of the steel reinforcement in the form of a table is known as Bar bending Schedule. The tabulation of the reinforcement details can be conviniently done using the MS Excel.
Professional contracting firms have got printed formats for BBS ready for the use of their staff. The BBS is prepared by the Qauntity Surveyors during estimation . The BBS is also prepared by the Site Engineers for controlling the quality of the Reinforcement Bars at site. The BBS is also an excellent tool for recording the measurements of the Reinforcement bars at site and the BBS can also be used to submit the Bills for the Reinf..bars.
This is a chart which basically gives the micro details about the various bars. This gives the dia, shape of bar , cutting length of the various bars in a RCC element such as Footing, column , beam ,slab etc.
The site engineer prepares the BBS based on the drawing and after due verification , hands it over to the reinforcement fitter.
By the use of BBS , the weight of the Re-bars can be easily calculated.
Let me explain you this popular tool with an example.
Imagine , there is a beam of the following cross section.
The details of the reinforcement have been tabulated in the following table :
The cutting lengths of each bar is calculated and tabulated as follows :
But you can see that many details are missing from this abstract. Hence , a better tabulation , known as the BBS has been prepared which gives each details of the Re-bar in a crystal clear method :
The bar bending gives a very clear picture of the reinforcement.