What is Bar Bending Schedule and Correct Concrete Reinforcement

Bar bending schedule or bar scheme diagram is the comprehensive representation of cut and bend bars as per the design requirements of reinforcement detailer. It helps in determining appropriate material quantities, strength and cost estimation.

Bar bending schedule is used as a guide in positioning various structural members such as footings, beams, columns, girders, piles, walls, etc upon casting.

Some examples are the bending of hooks, bending of stirrups & ties, meeting point of the top and bottom bars, bend for anchorages, bend of bars in slabs, U straps, and bend for longitudinal position of re-bars. Bar scheme diagram requires a thorough structural analysis for better safety and stability of the concrete structure.

In the UK, BS 8666:2000 standard specifies requirements for bar bending, scheduling, dimensioning and cutting of reinforcing steels. BS8666 has gradually replaced old BS 4466 standard which is still being used in some contracts. The discrepancy in shape codes between these standards is significant and sometimes lead to contradiction. Hence, it is crucial that the standard being used is clearly stated on the schedule.

The bar bending schedule is used to communicate requirements for cut & bent shapes from the detailer to the fabricator. The schedule contains specialized notes to describe various reinforcing materials available in the market – including different grades of standard stainless steels (BS6744), carbon steels (BS4449) & special steels.

Although the process of cutting and bending of reinforcement is relatively complex, the fabricator is well equipped to do the job within a definite set of quality management criteria. The precision of cutting and bending activities is crucial to ensure appropriate fit on site and to facilitate necessary anchorage lengths, lap lengths and cover.

In recent times basic practices of cutting and bending have changed considerably due to increased use of computer control, automation and IT systems. A recent development is carpet reinforcement which consists of a series of reinforcing bars welded to a lean steel strip. It can be rolled up like a carpet and is suitable for reinforcement of many types of slabs. It is observed that carpet system can offer savings of up to 30-40% in material & 80-90% in fixing costs!

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