GB 55008-2021Code for design of concrete structures (English PDF)

1.0.3 Whether the technical methods and measures adopted in engineering construction

comply with the requirements of this Code shall be determined by the relevant responsible parties. Among them, innovative technical methods and measures shall be demonstrated and meet the performance requirements of this Code.

3.1 Concrete

3.1.1 The main control indicators of cement used in structural concrete shall include cementation time, stability, mortar strength and chloride ion content. The type and quantity of mixed materials used in cement shall be clearly stated in the exit-factory documents.

3.1.2 The sand used for structural concrete shall meet the following requirements.

3.1.3 The firmness indicator of coarse aggregate for structural concrete shall not be greater than 12%. For concrete with impermeability, frost resistance, corrosion resistance, wear resistance or other special requirements, the mud content and mud block content in the coarse aggregate shall not exceed 1.0% and 0.5% respectively. The firmness indicator shall not be greater than 8%. The mud content and mud block content of coarse aggregate for high-strength concrete shall not be greater than 0.5% and 0.2% respectively.

3.1.4 Admixtures for structural concrete shall meet the following requirements.

3.1.5 Concrete mixing water shall control pH, sulfate ion content, chloride ion content, insoluble content, soluble content. When the concrete aggregate has alkali activity, the alkali content shall also be controlled. Surface water, ground water, and reclaimed water shall be tested for radioactivity before first use.

4.1 General provisions

4.1.1 The action on the concrete structure and the calculation of its action effect shall meet the following requirements.

4.1.2 The seismic fortification objectives and anti-seismic measures of concrete

structures shall be determined according to the seismic fortification intensity of the project location, site category, design earthquake grouping, project's seismic fortification category, and seismic performance requirements.

4.1.3 When the stress expression is used to calculate the limit state of the bearing capacity of concrete structural components, the following requirements shall be met.

4.1.4 The prefabricated concrete structure shall determine the connection structure method and carry out connection and node design according to the structural performance and the convenience requirements of component production and installation construction.

4.1.5 The connection between concrete structural components and between non-

structural components and structural components shall comply with the following requirements.

4.2 Structural system

4.2.1 The concrete structural system shall meet the load-bearing capacity, stiffness and ductility performance requirements of the project.

4.2.2 The design of the concrete structure system shall meet the following requirements.

4.2.3 The concrete floor of the house building shall meet the requirements of vertical vibration comfort of the floor. Concrete structure high-rise buildings shall meet the vibration comfort requirements of the 10-year return period horizontal wind load.

4.3 Structural analysis

4.3.4 When using static or dynamic elastic-plastic analysis methods for structural

analysis of concrete structures, the following requirements shall be met.

4.3.5 Concrete structures shall be analyzed and calculated for overall structural stability and anti-overturning calculations and shall meet the safety requirements required by the project.

4.3.6 For concrete structures or structural components with long spans and long

cantilevers, when the seismic fortification intensity is not lower than 7 degrees (0.15g), the calculation and analysis of vertical seismic action shall be carried out.

4.4 Component design

4.4.1 Concrete structural components shall be calculated according to the stress conditions of normal section, oblique section, twisted section, punching shear and local compression. For concrete structures or components subjected to dynamic cycles, the fatigue bearing capacity of the components shall also be checked.

5.1 General provisions

5.1.1 The construction of concrete structures shall ensure the realization of the design requirements and shall comply with the following regulations.

5.1.2 Materials, components, utensils and semi-finished products shall be inspected and accepted at the site. They can only be used after they are accepted.

5.1.3 Acceptance of concealed works shall be carried out and records shall be made.

5.1.4 When the formwork is removed, the prefabricated components are lifted, and the prestressed tendons are stretched and released, the concrete specimens cured under the same conditions shall reach the specified strength.

5.1.5 The appearance quality of concrete structures shall not have serious defects and dimensional deviations that affect structural performance and use functions.

5.1.6 Physical quality inspection shall be carried out for representative parts involving the safety of concrete structures.

5.2 Template engineering

5.2.1 Templates and supports shall be designed according to various control conditions during the construction process. They shall meet the bearing capacity, stiffness and overall stability requirements.

5.2.2 Templates and supports shall ensure that the shape, size and position of each part of the concrete structure and components are accurate.

5.3 Steel bars and prestressing works

5.3.1 Rebar mechanical or welded joint test pieces shall be taken from the completed entity. The performance test shall be carried out according to the regulations.

5.4 Concrete works

5.4.1 It is strictly forbidden to add water during concrete transportation, conveying and pouring. Concrete scattered during transportation, conveying and pouring is strictly prohibited to be used for structural pouring.

5.4.2 The strength grade of structural concrete shall be inspected and evaluated. The test pieces shall be randomly selected at the pouring site.

5.5 Prefabricated structural engineering

5.5.1 The connection of prefabricated components shall meet the design requirements and shall comply with the following regulations.

5.5.2 The joint surface of prefabricated composite components and the joint surface of

prefabricated component connection nodes shall be treated and cleaned according to the design requirements. Post-cast concrete shall be full and dense.

6.1 General provisions

6.1.1 For concrete structures, it shall establish a structure use and maintenance management system throughout the life cycle according to the structure type, safety level and use environment.

6.1.2 A maintenance database and information management platform shall be established for important concrete structures.

6.1.3 Demolition of concrete structure works shall be schematically designed. Measures shall be taken to ensure the safety of the dismantling process. The demolition of prestressed concrete structures shall still analyze the prestressing release procedure.

6.1.4 Demolition of concrete structures shall follow the principles of reduction, recycling and reusing. A waste disposal plan shall be developed.

6.2 Structure maintenance

6.2.1 Routine maintenance of concrete structures shall check the structural appearance and load changes. With regard to the appearance of structural components, inspections shall focus on cracks, deflection, freeze-thaw, corrosion, corrosion of steel bars, shedding of protective layers, water leakage, uneven settlement, artificial openings,

6.2.2 For concrete structures in harsh environments, a targeted maintenance plan shall be developed.

6.2.3 When one of the following conditions is met, the structure shall be tested and identified.

6.2.4 When there is any objection to the cement stability of hardened concrete, the potential hazard of free calcium oxide in cement shall be tested.

6.2.5 The structural performance and safety of the following concrete structures shall be monitored.

6.2.6 Inspections and system maintenance shall be carried out during the monitoring period. During special circumstances such as typhoons and floods, the frequency of monitoring shall be increased.

6.2.7 Concrete structure monitoring shall set monitoring and early warning value. The monitoring and early warning value shall meet the requirements of engineering design and control of the monitored objects.

6.2.8 Bridge structures that have exceeded the structural design working life or have a service life of more than 50 years shall be inspected and evaluated. The testing and evaluation cycle shall not exceed 10 years.

6.3 Structure disposal

6.3.1 When one of the following situations occurs, measures to eliminate potential

safety hazards shall be taken.

6.3.2 After testing and identification, the structures with potential safety hazards shall be dealt with by safety management measures.

6.4 Demolition

6.4.1 The structural analysis of the demolition project shall meet the following requirements.

6.4.2 The demolition operation shall comply with the following regulations.

6.4.3 Measures shall be taken to reduce noise, dust, sewage, vibration, impact and environmental pollution during demolition operations.

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