Bl.— This standard refers to steel bars, cold twisted on their own axis, to be used in the reinforcement of concrete pieces and structures. Consequently, those formed by 2 bars twisted together are not included. B2.— This standard deals with bars that are originally provided with 2 ribs arranged longitudinally and diametrically opposite, so that once the bar is twisted, said ribs adopt a helical arrangement.
UNIT 145-1961 history
1961UNIT 145-1961 Longitudinal cross-ribbed cold steel bars for use in concrete