11.1 Reinforcement shall be bent and fixed in accordance with procedure specified in good practice . The high strength deformed steel bars should not be re-bent or straightened without the approval of Engineer-in-Charge.
Bar bending schedules shall be prepared for all reinforcement work.
11.2 All reinforcement shall be placed and maintained in the position shown in the drawings by providing proper cover blocks, spacers, supporting bars, etc.
11.2.1 Crossing bars should not be tack-welded for assembly of reinforcement unless permitted by Engineer-in-Charge.
11.3 Placing of Reinforcement
Rough handling, shock loading (prior to embedment) and the dropping of reinforcement from a height should be avoided. Reinforcement should be secured against displacement outside the specified limits.
11.3.1 Tolerances on Placing of Reinforcement
Unless otherwise specified by Engineer-in-Charge, the reinforcement shall be placed within the following tolerances:
a) For effective depth 200 mm : ±10 mm or less
b) For effective depth more : ±15 mm than 200 mm
11.3.2 Tolerance for Cover
Unless specified otherwise, actual concrete cover should not deviate from the required nominal cover by mm.
Nominal cover as given in 25.4.1 should be specified to all steel reinforcement including links. Spacers between the links (or the bars where no links exist) and the formwork should be of the same nominal size as the nominal cover.
Spacers, chairs and other supports detailed on drawings, together with such other supports as may be necessary, should be used to maintain the specified nominal cover to the steel reinforcement. Spacers or chairs should be placed at a maximum spacing of 1 m and closer spacing may sometimes be necessary.
Spacers, cover blocks should be of concrete of same strength or PVC.
11.4 Welded Joints or Mechanical Connections
Welded joints or mechanical connections in reinforcement may be used but in all cases of important connections, test shall be made to prove that the joints are of the full strength of bars connected. Welding of reinforcements shall be done in accordance with good practices [6-5A(30)].
11.5 Where reinforcement bars upto 12 mm for high strength deformed steel bars and up to 16 mm for mild steel bars are bent aside at construction joints and afterwards bent back into their original positions, care should be taken to ensure that at no time is the radius of the bend less than 4 bar diameters for plain mild steel or 6 bar diameters for deformed bars. Care shall also be taken when bending back bars, to ensure that the concrete around the bar is not damaged beyond the bend.
11.6 Reinforcement should be placed and tied in such a way that concrete placement be possible without segregation of the mix. Reinforcement placing should allow compaction by immersion vibrator. Within the concrete mass, different types of metal in contact should be avoided to ensure that bimetal corrosion does not take place.