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Anonymous users2024-02-06The round steel is identified as HPB235, and the diameter of the general use is , and the thicker one is not commonly used, and the most commonly used is 8, which is generally used as stirrups.
The common identification of rebar is HRB335, the diameter of the general use is 12 to 22 even number, and then the coarse generally appears in large-volume concrete engineering, not commonly used, generally below 25 is the most commonly used, and brick-concrete structures below 16 common. As for HRB400 and HRB500, it is generally not common, at least not commonly used in general industrial and civil buildings.
Calculation method of tensile force of steel bar:
Grade 1 steel (HPB235).
d=8～20
Intensity standard value = 235
Tensile strength design value = 210
Compressive strength design value = 210
Grade 2 steel (HRB235).
d=6～50
Strength standard value = 335
Tensile strength design value = 300
Compressive strength design value = 300
Grade 3 steel HRB400
d=6～50
Strength standard value = 400
Tensile strength design value = 360
Compressive strength design value = 360
Grade 4 steel HRB400
d=8～40
Strength standard value = 400
Tensile strength design value = 360
Resistant to stress. The round steel is identified as HPB235, and the diameter of the general use is , and the thicker one is not commonly used, and the most commonly used is 8, which is generally used as stirrups.
The common identification of rebar is HRB335, the diameter of the general use is 12 to 22 even number, and then the coarse generally appears in large-volume concrete engineering, not commonly used, generally below 25 is the most commonly used, and brick-concrete structures below 16 common. As for HRB400 and HRB500, it is generally not common, at least not commonly used in general industrial and civil buildings.
Calculation method of tensile force of steel bar:
Grade 1 steel (HPB235).
d=8～20
Intensity standard value = 235
Tensile strength design value = 210
Compressive strength design value = 210
Grade 2 steel (HRB235).
d=6～50
Strength standard value = 335
Tensile strength design value = 300
Compressive strength design value = 300
Grade 3 steel HRB400
d=6～50
Strength standard value = 400
Tensile strength design value = 360
Compressive strength design value = 360
Grade 4 steel HRB400
d=8～40
Strength standard value = 400
Tensile strength design value = 360
Compressive strength design value = 360
The diameter unit is mm, and the strength unit is n mm2
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Anonymous users2024-02-051. Divide according to the size of the diameter.
Steel wire (diameter 3 5mm), thin steel bar (diameter 6 10mm), thick steel bar (diameter greater than 22mm).
2. According to mechanical properties.
grade reinforcement (235 420 grade); grade reinforcement (335 455 grade); Grade bars (400 540) and grade bars (500 630).
The reinforcement arranged in the reinforced concrete structure can be divided into the following types according to its function and use:
1. Stressed tendon - steel bar that bears tensile and compressive stress.
2. Stirrups - bear a part of the oblique tensile stress and fix the position of the stress bars, which are mostly used in beams and columns.
3. Erection bar - used to fix the position of the steel hoop in the beam to form the steel skeleton in the beam.
4. Distributed ribs - used in roof panels and floor slabs, arranged perpendicular to the stressed ribs of the slab, the weight of the bearing is evenly transmitted to the stressed ribs, and the position of the stressed ribs is fixed, as well as the temperature deformation caused by thermal expansion and contraction.
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Anonymous users2024-02-04Type of reinforcing bar.
Commonly used hot-rolled steel bars are divided into four grades: HPB235, HRB335, HRB400 and HBB500 according to the strength level.
The steel bars used in reinforced concrete structures include hot-rolled steel bars, waste heat treated steel bars, steel strands, cold-rolled ribbed steel bars, cold-drawn steel bars, cold-drawn steel wires, cold-rolled twisted steel bars, etc.
Hot-rolled steel bars are finished steel bars formed by hot rolling and naturally cooled, which are divided into hot-rolled round steel bars and hot-rolled ribbed steel bars.
The hot-rolled round steel bar is HPB235 grade steel bar; The hot-rolled ribbed steel bar has a crescent rib steel bar and a contour rib steel bar, and the crescent rib steel bar is HBB335 and HRB400 grade steel bar; The contour rib reinforcement is HBB500 grade reinforcement.
The strength standard value of ordinary steel bars is fyk(n mm2):
Species symbol d(mm) fyk
Hot rolled steel bars. New HPB235(Q235) 8 20 235
Old grade (A3, AY3) 235
New HRB335(20mnsi) 6 50 335
Old grade (20mnsi, 20mnb(b)) d 25 335
d=25∽40 315
New HRB400 (20MNSIV, 20MNSINB, 20MNTTI) O 6 50 400
Old grade (25mnsi) o 370
New RRB400 (K20MNSI) or 8 40 400
Legacy (40si2mnv, 45simnv, 45si2mnti) o 540
Note (new): 1. The diameter of the hot-rolled steel bar d refers to the nominal diameter;
Design values of tensile and compressive strength of ordinary steel bars fy, fy'(n mm2):
Species symbol d(mm) fy fy'
Hot rolled steel bars. New HPB235(Q235) 8 20 210 210
Old (A3, AY3) 210 210
New HRB335(20mnsi) 6 50 300 300
Old grade (20mnsi, 20mnb(b)) d 25 310 310
d=25∽40 290 290
New HRB400 (20MNSIV, 20MNSINB, 20MNTIi) o 6 50 360 360
Old grade (25mnsi) o 340 340
New RRB400 (K20MNSI) or 8 40 360 360
Legacy (40si2mnv, 45simnv, 45si2mnti) o 500 400
Note (new): In the reinforced concrete structure, when the design value of the tensile strength of the axial tension and small eccentric tension members is greater than 300n mm2, it should still be taken with 300n mm2.
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Anonymous users2024-02-03Process properties of steel bars:
1. Bending performance:
After the bending diameter of the bending center specified in the following table is bent by 180 degrees, no cracks shall occur on the surface of the bending part of the steel bar. The nominal diameter of the grade is a
2. Reverse bending performance:
According to the requirements of the buyer, the rebar can be tested for reverse bending performance.
The bending diameter of the reverse bend test is correspondingly increased by one bar diameter compared to the bending test. First bend 45 degrees in the forward direction, then 23 degrees in the reverse direction, and then 23 degrees in the reverse direction. After the reverse bending test, no cracks shall occur on the surface of the bending part of the steel bar.
Classification of rebar:
1. Divide according to the size of the diameter.
Steel wire (diameter 3 5mm), thin steel bar (diameter 6 10mm), thick steel bar (diameter greater than 22mm).
2. According to mechanical properties.
grade reinforcement (300 420 grade); grade reinforcement (335 455 grade); Grade bars (400 540) and grade bars (500 630).
3. According to the production process.
The steel bar of hot-rolled, cold-rolled, cold-drawn, and the heat-treated steel bar that is made of grade steel bar by heat treatment, the strength is higher than the former;
4. According to the role in the structure.
Compression reinforcement, tension reinforcement, erection reinforcement, distribution reinforcement, stirrups.
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Anonymous users2024-02-02The easiest way to do this is to count the laps with a few bars and poles.
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Anonymous users2024-02-01How to classify the grade of reinforcement.
A: Reinforcement grade:PressYield strengthEigenvalue grading. Classification: HPB, HRB, RRB, HRBF.
The grades and symbols of ordinary steel bars are shown in the following table (extracted from the "Code for Design of Reinforced Concrete" GB50010-2010):
The symbol of ordinary steel bar in the code for reinforced concrete design GB50010-2010 only represents the grade of ordinary steel bar. The meaning of the composition of the grade (excerpted from "Steel for Reinforced Concrete Part I: Hot Rolled Round Steel Bar":
Hot Rolled Round Bar Grade: HPB300 Composition Meaning: Composed of HPB yield strength eigenvalues (300MPa).
Meaning of the English letters: HPB - the abbreviation of hot rolled plain bars. Design Symbols:
Steel for Reinforced Concrete Part 2: Hot-rolled ribbed steel bar.
Ordinary hot-rolled ribbed steel bar grades: HRB335, HRB400, HRB500; Composition meaning of grade: Composed of characteristic values of HRB yield strength (335MPa, 400MPa, 500MPa).
On the rebar, the grade markings are denoted by . English letter meaning: HRB - the English abbreviation of hot rolled ribbed bars.
Fine-grained hot-rolled steel bar grades: HRBF 335, HRBF400, HRBF 500;Composition meaning of grade: Composed of HRBF yield strength eigenvalues (335MPa, 400MPa, 500MPa).
On the rebar, the grade mark is C3, C4 and C5 respectively. HRBF English letter meaning: HRB - the abbreviation of hot rolled ribbed bars (hot rolled ribbed bars) followed by the first letter of "fine".
Waste heat treated ribbed steel bar grade: RRB400, the composition meaning of the grade: It is composed of the characteristic value of RRB yield strength (400MPa). RRB - Waste heat treatment of ribbed steel bars in English (Remainedheat Treatment
Ribbed Steel Bars).
Bars
Ribbed
Remained
According to the GB50010-2010 table of the "Code for the Design of Reinforced Concrete", the steel bar only has grades, symbols, standard values of yield strength and standard values of ultimate strength.
Steel for Reinforced Concrete Part I: Hot Rolled Round Steel Bar and Steel for Reinforced Concrete
Part 2: Hot Rolled Ribbed Steel Reinforcement Look,Rebar is no longer called "grade".Only the category, grade, according to the yield strength characteristic value grade.
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