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Construction engineering in the classification of steel

There are many types of rebar. The commonly used classification is usually based on chemical composition, production process, rolling shape, supply form, diameter size, and use in the structure:

By the rolling shape:

  1. Smooth steel: Grade A steel bar (Q235 steel bar) are rolled for smooth circular section, the supply form has a disc, diameter not more than 10mm, length of 6m ~ 12m.
  2. Ribbed rebar: There are three kinds of spiral, herringbone and crescent shape. Generally, grade II and grade III rebar are rolled into chevron shape, grade IV rebar is rolled into helical shape or crescent shape.
  3. Steel wire (divided into low carbon steel wire and two kinds of carbon steel) and steel wire.
  4. Cold rolled and twisted steel bar: cold rolling and cold twisted forming.

By diameter:

  1. Steel wire diameter 3,4,5mm.
  2. Fine rebar diameter 6, 8, 10 mm.
  3. Thick steel bar (diameter 12, 14, 16, 18, 20, 22, 25, 28, 30 mm).

By intensity levels:

  1. Grade I Q235 / HRB235
  2. Grade II HRB335
  3. Grade III Steel HRB400
  4. Grade IV steel with letters in the upper right corner such as φ R.

By the intensity level:

(the new specification corresponds to the following, the new standard cancels the name of the level, and reads the English letters and numbers directly)

  1. Grade I HPB300
  2. Grade II HRB335 HRF335
  3. Grade III Steel HRB400 HRBF 400 RRB 400
  4. Grade IV Steel HRB500 HRBF 500

By the production technology:

Hot rolled, cold rolled, cold-drawn steel bars, as well as grade IV steel bars by heat treatment of the heat treated steel, the strength is higher than the former.

By the roles in the structure:

  1. Stress reinforcement – to withstand tensile and compressive stresses of the steel.
  2. Stirrup – to withstand a portion of the cable tension stress, and fixed the location of the force of the reinforcement, mostly used in beams and columns.
  3. Erecting Bar – used to fix the position of the steel hoop in the beam, and form the steel bar framework within the beam.
  4. Distributed reinforcement – for the roof board, floor, and the plate force reinforcement vertical layout, will bear the weight evenly to the force reinforcement, and fixed force reinforcement position, and resistance to thermal expansion and contraction caused by temperature deformation.
  5. Other – due to the structural requirements of components or construction and installation needs and configuration of the structure of the bar. Such as waist bar, embedded anchor bar, ring, etc.


By the position in the component:

  1. in the board: called gluten, bottom bar, middle bar.
  2. in the beam: called the upper bar, lower waist bar.
  3. in the column: called corner reinforcement, side longitudinal reinforcement, lateral stirrup, inner stirrup.
  4. in the wall: longitudinal force bars, horizontal force bars.