JGJ 115-1997 Technical Specification for Cold-rolled Twisted Reinforced Concrete Members JGJ115-97 JGJ115-1997 Standard download decompression password: www.bzxz.net

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Industry Standard of the People's Republic of China
Technical specification for concrete structural element with cold-rolled and twisted bars JGJ
115—97
1998 Beijing
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Industry Standard of the People's Republic of China
Technical specification for concrete structural element with cold-rolled and twisted bars bars11597
Editing unit: Beijing Institute of Architectural DesignApproving department: Ministry of Construction of the People's Republic of ChinaEffective date: July 1, 1998
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Notice on the release of the industry standard "Technical Code for Concrete Main Components with Cold-rolled Twisted Rebars"
Construction Standard [1998] No. 23
Construction Committees (Construction Departments) of all provinces, autonomous regions, and municipalities directly under the Central Government, Construction Committees of cities with independent planning status, and relevant departments of the State Council:
In accordance with the requirements of the Ministry of Construction's Construction Standard [1994] No. 314, the "Technical Code for Concrete Main Components with Cold-rolled Twisted Rebars" edited by Beijing Institute of Architectural Design has been reviewed and approved as an industry standard, with the number JGJ115-97, and will be implemented on July 1, 1998. This code is managed by the China Academy of Building Research, the technical unit responsible for building engineering standards under the Ministry of Construction, and is interpreted by the Beijing Institute of Architectural Design. This code is published by the Standard and Norms Research Institute of the Ministry of Construction. Ministry of Construction of the People's Republic of China
February 9, 1998
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2 Terms and Symbols
2.1 Terms
2.2 Symbols.·
3 Materials
3.1 Concrete
3.2 Cold-rolled twisted steel bars
Basic design provisions
Ultimate state calculation of bearing capacity
6 Verification of normal service limit state·
6.1 Verification of crack width
6.2 Verification of deflection of flexural members
|7 Structural regulations
Concrete protective layer
7.2 Anchorage and joints of cold-rolled twisted steel bars
7.3 Minimum reinforcement percentage of cold-rolled twisted steel bars
++中++
8 Construction of cold-rolled twisted steel bar concrete components·次
8.1 Acceptance and re-inspection of finished cold-rolled twisted steel bars8.2 Construction of cold-rolled twisted steel bar concrete components…5
Appendix A Replacement of tensile strength design of cold-rolled twisted steel bars and grade I steel bars···22
0000000
Appendix B Calculation method of cross-sectional area of ​​longitudinal tensile steel bars in cold-rolled twisted steel bar concrete rectangular section flexural members． ……
Appendix C for cold-rolled and twisted reinforced concrete flexural members that do not require crack width verification
Maximum steel bar diameter
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Appendix D for cold-rolled and twisted reinforced concrete flexural members that do not require deflection verification
E Explanation of terms used in this code
Appendix E
Additional explanation
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1 General
1.0.1 This code is formulated to implement the national technical and economic policies in the design and construction of cold-rolled and twisted reinforced concrete structures, to achieve advanced technology, safety and applicability, economic rationality, and quality assurance.
2 This code is applicable to the design and construction of cold-rolled and twisted reinforced concrete flexural members that do not directly bear dynamic loads in industrial and civil buildings and general structures. 1.0.3 This code adopts the limit state design method based on probability theory, measures the reliability of structural components with reliability indicators, and uses the design expression based on partial coefficients for design.
The design and construction of cold-rolled and twisted reinforced concrete components shall comply with the provisions of the relevant national standards in addition to complying with this code. Engineering Construction Standard Full-text Information System
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2 Terms and Symbols
2.1 Terms
2.1.1 Cold-rolled and twisted bars Cold-rolled and twisted bars are continuous spiral bars with specified cross-sectional shapes and pitches, which are formed by straightening, cold rolling and cold twisting of hot-rolled round wire rods of low-carbon steel through a special steel bar cold rolling and twisting machine. 2.1.2 Pitch
The forward distance when the cross-sectional position of the cold-rolled and twisted steel bar is rotated 180° along the axis of the steel bar. 2.1.3 Rolled thickness (Rolledthickness) The smaller side dimension of the rectangular section or the short diagonal dimension of the rhombus section after the cold-rolled and twisted steel bar is formed.
2.1.4 Mark diameter (Markdiameter) The nominal diameter of the raw material (parent material) before cold rolling and twisting. 2.2 Symbols
2.2.1 Material properties
E-elastic modulus of cold-rolled and twisted steel bar;
E. —elastic modulus of concrete;
f. —design value of axial compressive strength of concrete; fcm——design value of bending compressive strength of concrete f——standard value of axial tensile strength of concrete; f——design value of axial tensile strength of concrete, f—standard value of tensile strength of cold-rolled and twisted steel bar; f,—design value of tensile strength of cold-rolled and twisted steel bar; f',—design value of compressive strength of cold-rolled and twisted steel bar. 2.2.2 Actions and effects of actions
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M——Design value of bending moment;
M.-Bending moment value calculated according to the combination of short-term effects of loads; Mt-Bending moment value calculated according to the combination of long-term effects of loads; V
-Design value of shear force,
-Stress of longitudinal cold-rolled torsion steel bars in tension calculated according to the combination of short-term effects of loads,
-Short-term stiffness of bending members under the action of the combination of short-term effects of loads; Bt——Long-term stiffness of bending members according to the combination of short-term effects of loads and considering the influence of the combination of long-term effects of loads;
Maximum crack width considering the uneven distribution of crack width and the influence of the combination of long-term effects of loads.
Geometric parameters
-Cross-sectional area of ​​longitudinal cold-rolled torsion steel bars in tension zone; As
A'. 1. Cross-sectional area of ​​longitudinal cold-rolled twisted steel bar in compression zone; effective cross-sectional area of ​​tensile concrete;
2. Distance from the point of action of the combined force of longitudinal cold-rolled twisted steel bar in tension to the near side of the section; 3. Distance from the point of action of the combined force of longitudinal cold-rolled twisted steel bar in tension to the near side of the section; 4. Distance from the point of action of the combined force of longitudinal cold-rolled twisted steel bar in compression to the near side of the section; 5. Width of rectangular section, web width of T-shaped and I-shaped sections; 6. Flange width of inverted T-shaped and I-shaped sections in tension zone; 7. Flange width of T-shaped and I-shaped sections in compression zone; 8. Thickness of concrete cover; 9. Marking diameter of cold-rolled twisted steel bar, i.e. nominal diameter of parent material before rolling; 10. Equivalent diameter of cold-rolled twisted steel bar; 11. Diameter of cold-rolled twisted steel bar converted according to the circumference of the section; 12. Height of section; 13. Ho distance from the point of action of the combined force of longitudinal cold-rolled twisted steel bar in tension to the edge of the compression zone of the section; 14. —The distance from the combined force point of the longitudinal compression reinforcement to the edge of the tensile zone of the section; ht—the flange height of the tensile zone of the inverted T-shaped and I-shaped sections; Engineering Construction Standard Full Text Information System
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hT-shaped and I-shaped section flange height of the compression zone, l. —The minimum anchorage length of the longitudinal tensile cold-rolled twisted reinforcement; lo——calculated span;
l—the anchorage length of the tensile cold-rolled twisted reinforcement in the lower part of a simply supported beam extending into the support l—the pitch value of the cold-rolled twisted reinforcement;
t—the flattened thickness of the cold-rolled twisted reinforcement;
u——the total circumference of the longitudinal tensile cold-rolled twisted reinforcement section; —the height of the concrete compression zone;
——the height of the concrete limit compression zone;
%6—the height of the relative limit compression zone.
2.2.4 Calculation coefficients and others
Ratio of elastic modulus of cold-rolled twisted steel bar to elastic modulus of concrete; Reinforcement ratio of longitudinal tensile cold-rolled twisted steel bar;
——Influence coefficient of long-term load effect combination on deflection increase; 36
——Strain non-uniformity coefficient of longitudinal tensile cold-rolled twisted steel bar between cracks; P. ——Reinforcement ratio of longitudinal tensile cold-rolled twisted steel bar calculated based on effective tensile concrete cross-sectional area;
yt——Ratio of tensile flange area to effective web area; 10——Elongation measured with 10 times the nominal diameter of cold-rolled twisted steel bar parent material as gauge length.
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3.1 Concrete
Concrete strength grade, strength standard value, strength design value, elastic modulus, etc., 3.1.1
All should be determined in accordance with the provisions of the current national standard "Concrete Structure Design Code" GBJ10. 2 The concrete strength grade of cold-rolled twisted steel bar concrete components should not be lower than C20. 3.1.2
3.2 Cold-rolled twisted steel bars
The quality of cold-rolled twisted steel bars should comply with the provisions of the current industry standard "Cold-rolled twisted steel bars" JG3046.
The specifications and cross-sectional parameters of cold-rolled twisted steel bars should be adopted according to Table 3.2.2. Specifications and cross-sectional parameters of cold-rolled twisted steel bars
Marking diameter a (mm)
Nominal cross-sectional area
Nominal weight
G (kg/m)
. Type I is a rectangular cross-section, and type I is a diamond cross-section. Note: 1.
Equivalent diameter
do (mm)
2. Equivalent diameter &. The diameter of the circular cross-section equivalent to the nominal cross-sectional area. Engineering Construction Standard Full-text Information System
Cross-sectional circumference
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3 The external dimensions of cold-rolled twisted steel bars shall comply with the provisions of Table 3.2.3. 3.2.3
Overall dimensions of cold-rolled twisted steel bars (mm)
Marked diameter
Flattened thickness
≤110
≤150
The standard strength value, design value and elastic modulus of cold-rolled twisted steel bars shall be adopted according to Table 3.2.4.
Standard value, design value and elastic modulus of strength of cold-rolled twisted steel bars (N/mm2) Table 3.2.4
Standard value of tensile strength
Design value of tensile strength
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Design value of compressive strength
Elastic modulus
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4 Basic design provisions
4.0.1 The safety level of cold-twisted steel bar concrete structure components in the service stage should be the same as the safety level of the entire structure, and the safety level of all components shall not be lower than level three in each stage such as the construction stage and the service stage. 4.0.2 The bearing capacity calculation of structural components shall adopt the load design value in accordance with the provisions of the current national standard "Code for Loads on Building Structures" GBJ9; the corresponding load representative value shall be used for deformation and crack width verification.
4.0.3 For the serviceability limit state, structural members shall be verified according to the short-term effect combination, long-term effect combination or short-term effect combination and the influence of long-term effect combination. The allowance and maximum crack width shall comply with the limit values ​​specified in Table 4.0.4 and Table 4.0.5 of this Code.
4.0.4 The allowable deflection value of cold-rolled twisted steel bar bending members used for roofs, floors and stairs shall comply with the provisions of Table 4.0.4. The allowable deflection value of cantilever members can be obtained by multiplying the corresponding value in the table by a coefficient of 2.0. When the member is pre-arched during manufacture and it is also allowed in use, the calculated deflection value can be subtracted from the arch value when verifying the deflection. Allowable deflection of bending members
Member type
When lo<7m
When 7m<9m
Note: 1. To in the table is the calculated span,
Allowable deflection value
Zo/200(to/250)
lo/250（to/300）
2. The values ​​in brackets in the table are applicable to members with higher requirements for deflection in use. Table 4.0.4
5The maximum crack width of cold-rolled twisted steel bar bending members shall comply with the provisions of 4.0.5
in Table 4.0.5.
6Prefabricated members shall be verified in the construction stage according to the load design values ​​during production, transportation and installation. When checking the hoisting of components, the deadweight of the components should be multiplied by the standard information system for power system engineering construction.5
Regulations.
6 Prefabricated components should also be verified in the construction phase according to the load design values ​​during production, transportation and installation. When verifying the hoisting of components, the deadweight of the component should be multiplied by the power system engineering construction standard full text information system
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Regulations.
6 Prefabricated components should also be verified in the construction phase according to the load design values ​​during production, transportation and installation. When verifying the hoisting of components, the deadweight of the component should be multiplied by the power system engineering construction standard full text information system
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