See the following table for the brands and symbols of ordinary steel bars (extracted from Code for Design of Reinforced Concrete (GB500 10-20 10)):
The symbols of ordinary steel bars in Code for Design of Reinforced Concrete (GB500 10-20 10) only represent the grades of ordinary steel bars. Composition of brand number GB 1499. 1-2008:
Hot rolled round steel bar brand:? What is the meaning of HPB300 brand? By who? HPB？ +Characteristic value of yield strength (300MPa). ? English letter meaning: HPB- English is Hot rolled round steel bar (hot? Get out? Plain? Bar) abbreviation design symbol:? .
Steel for reinforced concrete Part 2: Hot rolled ribbed bars GB1499.2-2007);
Ordinary hot-rolled ribbed bar brand: HRB335, What do HRB400 and HRB500 brands mean? By who? HRB？ +Characteristic value of yield strength (335MPa, 400MPa and 500MPa). On the steel bar, the grades are indicated by 3, 4 and 5 respectively. English letter meaning: HRB- English is hot rolled ribbed steel bar (hot? Get out? Rib? Bar) abbreviation
Extended data:
Steel bars for reinforced concrete refer to straight steel bars or rolled steel bars used to strengthen reinforced concrete. Its shape can be divided into smooth circular reinforcement and deformed reinforcement, and the delivery state is straight and coiled.
Smooth round steel is actually a small round steel and coil of ordinary low carbon steel. Deformed steel bars are steel bars with ribs on the surface, usually with two longitudinal ribs and transverse ribs evenly distributed along the length. The shapes of transverse ribs are spiral, herringbone and crescent. Expressed in millimeters of nominal diameter. The nominal diameter of deformed steel bar is equivalent to the nominal diameter of smooth round steel with equal cross section. The nominal diameter of reinforcement is 8-50mm, and the recommended diameters are 8, 12, 16, 20, 25, 32 and 40 mm..
Steel grade: 20MnSi, 20MnV, 25MnSi, BS20MnSi. Steel bars mainly bear tensile stress in concrete. Deformed steel bars have great bonding ability with concrete due to the action of ribs, so they can better withstand the action of external forces. Steel bars are widely used in various building structures. Especially for large, heavy and light thin-walled and high-rise building structures.
If it is necessary to replace steel bars during construction, we must fully understand the design intent and the performance of the replacement materials, strictly abide by the provisions of the current reinforced concrete design code, and do not replace low-strength steel bars with high-strength steel bars of equal area. All the important parts of the steel bar replacement, must obtain the consent of Party A and the design unit, and issue a written notice before replacement.
(1) The surface of steel bar should be clean, and the attached oil stain, dirt and floating rust must be removed before use, and rust can be removed in combination with cold drawing process.
(2) Steel bar straightening can adopt mechanical or manual methods. Straightened steel bars should not have local bending, dead bending and small waves, and their surface scars should not reduce the cross section of steel bars by 5%.
(3) Steel bar cutting should be based on the number, diameter, length and quantity of steel bars, and the length should be matched. The long material should be cut first and then the short material should be cut, so as to minimize and shorten the short head of steel bars to save steel.
(4) steel hook or bending:
(1) steel hook. There are three forms, namely semi-circular hook, straight hook and inclined hook. After the steel bar is bent, the endothelial contraction, skin extension and axial length at the bend remain unchanged, and the bend forms an arc. The size after bending is larger than the blanking size, so the bending adjustment value should be considered. The bending center diameter of steel bar is 2.5d, and the straight part is 3d. The theoretical calculation value of reinforcement hook length increase is 6.5d for counter-rotating semi-circular hook, 3.5d for straight hook and 4.9d for oblique hook.
(2) Bending steel bar. The bending diameter d of the middle bend should not be less than 5 times the diameter of the steel bar.
③ Stirrups. The end of stirrups should be hooked, and the hook form should meet the design requirements. Stirrup adjustment, that is, the difference or sum of the increase length of the hook and the bending adjustment value, depends on the outer package size or inner package size of the stirrup.
(4) The blanking length of steel bar shall be specified according to the component size, the thickness of concrete protective layer, the adjustment value of steel bar bending and the increase length of hook.
A. blanking length of straight steel bar = member length-protective layer thickness+hook increase length,
B, bending steel blanking length = straight bending length+oblique bending length-bending adjustment value+hook increase length,
C stirrup blanking length = stirrup inner diameter+stirrup adjustment value+hook increase length.
References:
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