Binding wires are made from high quality carbon steel making them highly resistant to corrosion and abrasion. In RCC work where we use MS steel bars either plain or ribbed or tor, binding wires are used to bind the steel bars to each other at appropriate place according to design at a spacing defined by the drawing. The steel bars should not be disturbed while lying cements concrete in any of member such as column, beam, slab wall etc.
If the bars are disturbed than it will reduced the strength of RCC. So proper binding is necessary to intact the steel bars. Binding is usually done by hand with the help of hand tool but in heavy work big diameter steel bars some time bind with the help of welding.
Quality / Specification
Binding or fabrication of reinforcement shall be as per drawing and Bending shall be cold bending done either mechanically or with hand but to a correct radius with tools meant for the above work conform to IS 2502. Steel bars should be clear, free from loose mil scales, dust and loose rust coats of paints, oil or other coatings which may destroy or reduce bond strength. The bar is bent correctly and accurately to the size and shape as shown in drawings. The bar is bent correctly and accurately to the size and shape as shown in drawings. If possible, the bar of full length is used. Overlapping bars do not touch each other and these should be kept apart with concrete. The overlap if given should be staggered. The cranks in the bar at the end should be kept in position by using spots.
The binding wire should be 16 or 18 gauge annealed wire conforming to IS 280. It shall be free from rust, oil, paint, grease, loose mill scale or any type.
It shall be free from corrosion and abrasion and should be abrasion
Its tensile strength is half hard i.e. the Tensile Strength: 250-430 N/mm2.
and Elongation: 40 % @ measuring length of 5.0 x dia.Precaution while binding
The binding wire should be cut in to pieces from coil for binding.
Care should be taken that the length of wire should not be less than 4’’. Take 2 numbers wire and bind diagonally at joint tightly. Do not leave any joint, bind all the joints. At some places, there is a practice to bind alternately joints which is wrong practice and reinforcement may loose during laying RCC slab.