Historically in Europe, rebar comprised mild steel material with a yield strength of approximately 250 N/mm˛. Modern rebar comprises high-yield steel, with a yield strength more typically 500 N/mm˛. Rebar can be supplied with various grades of ductility, with the more ductile steel capable of absorbing considerably greater energy when deformed - this can be of use in design against earthquakes for example.
For clarity, reinforcement is usually tabulated in a Reinforcement Schedule on construction drawings. This eliminates ambiguity in the various notations used in different parts of the world. The following list provides examples of the different notations used in the architectural, engineering, and construction industry.
|#4 @ 12 oc, T&B, EW||Number 4 rebars spaced 12 inches on centre (centre-to-centre distance) on both the top and bottom faces and in each way as well, i.e. longitudinal and transverse|
|3 #4||Three number 4 rebars|
|#3 ties @ 9 oc, 2 per set||Number 3 rebars used as stirrups, spaced at 9 inches on centre. Each set consists of two ties, which is usually illustrated.|