Bar Bending Schedule (BBS) is a critical component of construction that specifies the shape, size, and cutting length of reinforcement bars used in concrete structures. To simplify the representation of different bar shapes, codes are assigned to various forms of bars. Below are examples of common bar shapes and their codes.
A straight bar is the simplest form of reinforcement with no bends or hooks. It is represented by a simple straight line in drawings and BBS.
Shape Code: 01
Example: A 12mm diameter straight bar of 5000mm length.
Bent bars are often used to provide anchorage or additional support at corners and edges. These bars have a single bend.
Shape Code: 02
Example: A 10mm diameter bar with a total length of 4000mm and a bend at 45°.
Cranked bars are used in slabs and beams to maintain reinforcement in both tension and compression zones. These bars are bent at specified angles to form a crank.
Shape Code: 03
Example: A 16mm diameter bar with a total length of 6000mm and two 45° bends at 1500mm from each end.
Stirrups are closed-loop bars used to hold the main reinforcement in place and resist shear forces. They are typically rectangular, square, or circular in shape.
Shape Code: 51
Example: A 8mm diameter rectangular stirrup of dimensions 300mm x 500mm.
U-shaped bars are used as links or to provide additional reinforcement at specific points in a structure.
Shape Code: 07
Example: A 10mm diameter U-shaped bar with legs of 500mm each and a base of 300mm.
L-shaped bars are used at corners or as anchorage bars in foundations and columns.
Shape Code: 12
Example: A 12mm diameter L-shaped bar with one leg of 600mm and the other leg of 400mm.
Understanding bar shape codes is essential for preparing an accurate BBS, ensuring efficient construction processes and minimizing material wastage. Each shape code corresponds to a specific bar configuration, simplifying the communication between designers, engineers, and construction teams.