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GB 50666-2011: Code for construction of concrete structures
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GB 50666-2011
Code for Construction of Concrete Structures
NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA
UDC
P GB 50666-2011
ISSUED ON: JULY 29, 2011
IMPLEMENTED ON: AUGUST 1, 2012
Issued by: Ministry of Housing and Urban-Rural Development of PRC;
General Administration of Quality Supervision, Inspection and
Quarantine of PRC.
Table of Contents
1 General Provisions ... 9
2 Terms ... 10
3 Basic Requirements ... 12
3.1 Construction Management ... 12
3.2 Construction Technology ... 12
3.3 Construction Quality and Safety ... 13
4 Formwork ... 15
4.1 General Requirements ... 15
4.2 Materials ... 15
4.3 Design ... 15
4.4 Fabrication and Installation ... 20
4.5 Removal and Maintenance ... 24
4.6 Quality Control ... 25
5 Reinforcement ... 27
5.1 General Requirements ... 27
5.2 Materials ... 27
5.3 Reinforcement Fabrication ... 28
5.4 Reinforcement Connection and Fixing ... 30
5.5 Quality Control ... 34
6 Prestressed Concrete ... 37
6.1 General Requirements ... 37
6.2 Materials ... 37
6.3 Fabrication and Installation ... 38
6.4 Post-tensioning and Pre-tensioning ... 42
6.5 Grouting and Anchorage Protection ... 46
6.6 Quality Control ... 48
7 Concrete Production and Transportation ... 51
7.1 General Requirements ... 51
7.2 Materials ... 51
7.3 Mix Proportioning ... 54
7.4 Mixing ... 57
7.5 Transportation ... 59
7.6 Quality Control ... 59
8 Cast-in-situ Concrete ... 63
8.1 General Requirements ... 63
8.2 Conveying ... 63
8.3 Placing ... 66
8.4 Compacting ... 72
8.5 Curing ... 73
8.6 Construction Joint and Post-cast Strip ... 75
8.7 Crack Control of Mass Concrete ... 77
8.8 Quality Control ... 80
8.9 Repair of Concrete Defects ... 82
9 Precast Concrete ... 85
9.1 General Requirements ... 85
9.2 Checking ... 85
9.3 Production ... 88
9.4 Storage and Transportation ... 90
9.5 Erection ... 91
9.6 Quality control ... 94
10 Construction in Cold, Hot and Rainy Weather ... 97
10.1 General Requirements ... 97
10.2 Cold Weather Requirements ... 97
10.3 Hot Weather Requirements ... 101
10.4 Rainy Weather Requirements ... 103
11 Environmental Protection ... 105
11.1 General Requirements ... 105
11.2 Environmental Considerations ... 105
Appendix A -- Characteristic Value of Loads Acting on Formwork ... 107
Appendix B -- Nominal Diameter, Nominal Sectional Area, Calculation Sectional Area and
Theoretical Weight of Common Reinforcement ... 110
Appendix C -- Minimum Splicing Length of Longitudinal Reinforcement ... 112
Appendix D -- Calculation and Measurement Method for Elongation of Prestressed
Tendon ... 114
Appendix E -- Testing Method for Prestressing Loss Due to Friction ... 116
Appendix F -- Specification of Concrete Materials ... 118
Explanation of Wording in This Code ... 124
List of Quoted Standards ... 125
1 General Provisions
1.0.1 This Code is formulated with a view to implementing the national technical and
economic policies, ensuring the engineering quality, and realizing advanced
technology, reasonable process, resources conservation and environmental
protection during the construction of concrete structures.
1.0.2 This Code is applicable to the construction of concrete structures in building
engineering, not to the construction of lightweight aggregate concrete and special
concrete.
1.0.3 This Code contains the basic requirements for the construction of concrete
structures. When there are special requirements for the construction stated in the
design documents, the construction shall also be implemented in accordance with the
design documents.
1.0.4 Construction of concrete structures shall not only meet the requirements of this
Code but also comply with those in the current relevant standards of the nation.
2 Terms
2.0.1 Concrete structure
The structure mainly made of concrete, including plain concrete structure, reinforced
concrete structure and prestressed concrete structure, which may be classified into
cast-in-situ concrete structure and precast concrete structure according to the
construction method.
2.0.2 Cast-in-situ concrete structure
The concrete structure that is made by erecting formwork in situ and integral casting,
hereinafter referred to as cast-in-situ structure.
2.0.3 Precast concrete structure
The concrete structure that is made by assembling and connecting the precast
concrete members or parts, hereinafter referred to as precast structure.
2.0.4 Workability of concrete
The features that shall be possessed of by the concrete mixture in order to meet the
construction operation requirements and ensure the concrete uniformity and
compactness, mainly including flowability, cohesiveness and water-retaining property.
It is hereinafter referred to as workability of concrete.
2.0.5 Self-compacting concrete
The concrete that can flow and be compacted under the action of deadweight,
dispensing with the vibration by external force.
2.0.6 Pre-tensioning
It is a kind of construction method that establishes prestress by firstly post-tensioning
the prestressed tendon on a pedestal or formwork and temporarily anchoring it with
grip, concreting and then pre-tensioning the prestressed tendon after the concrete
reaching a certain specified strength.
2.0.7 Post-tensioning
It is a kind of construction method that establishes prestress by post-tensioning the
prestressed tendon after the concrete of a structural member reaching a certain
3 Basic Requirements
3.1 Construction Management
3.1.1 The construction organizations for the concrete structures shall have
corresponding qualification and establish corresponding quality management system
as well as construction quality control and inspection system.
3.1.2 Organization structuring and manning of construction project department shall
meet the construction management requirements of concrete structures. Construction
operation personnel shall receive training to acquire the basic knowledge and skills
required for their respective posts.
3.1.3 Before construction, the development organization shall organize the design,
construction and supervision organizations to carry out the technical disclosure and
joint trial for the design documents. The in-depth design documents completed by the
construction organization shall be confirmed by the original design organization.
3.1.4 The construction organization shall ensure the authenticity, effectiveness,
integrity and completeness of the construction documents. Construction project
technical leader shall organize the data preparation, collection, arrangement,
examination and verification, and timely archiving and filing during the whole
construction process.
3.1.5 The construction organization shall establish specific construction schemes
according to the requirements of the design documents and construction organization
design, which shall be implemented after examined and approved by the supervision
organization.
3.1.6 Before construction of concrete structures, the construction organization shall
establish emergency plan upon the contingent hazards, disasters and emergencies at
the construction site. Technical disclosure and training shall be carried out for the
emergency plan, and drilling shall be carried out if necessary.
3.2 Construction Technology
3.2.1 Before construction of concrete structures, the construction process shall be
determined according to the structure types, characteristics and construction
conditions, and each preparation work shall be completed.
3.2.2 Construction process monitoring should be carried out and construction control
measures shall be timely adjusted for the concrete structures that have complex
shape, relatively large height or span, complex subgrade conditions and particular
construction environment conditions.
3.2.3 The new technologies, new processes, new materials and new equipment
adopted during the construction of concrete structures shall be evaluated and filed
according to the relevant requirements. The new construction processes or those
adopted for the first time shall be evaluated before construction, and special
construction schemes shall be established and verified by the supervision
organization.
3.2.4 The patented technologies adopted during the construction of concrete
structures shall not be in violation of the relevant requirements of this Code.
3.2.5 Effective environmental protection measures shall be taken during the
construction of concrete structures.
3.3 Construction Quality and Safety
3.3.1 Each procedure of concrete structures shall be constructed after qualified check
for the last procedure.
3.3.2 Self-inspection, mutual inspection and handover inspection shall be carried out
timely during the construction of concrete structures. The quality of concrete
structures shall not be lower than the relevant requirements of the current national
standard "Code for Acceptance of Constructional Quality of Concrete Structures" (GB
50204). The quality problems discovered during the inspection shall be settled
promptly according to the established procedures.
3.3.3 During the construction of concrete structures, efforts shall be made to accept
the concealed work, strengthen quality control or testing for the important procedures
and key positions, keep records in detail, and keep the image data.
3.3.4 Materials, products and equipment used during the construction of concrete
structures shall meet the requirements of the current relevant standards of the nation,
the design documents and the construction schemes.
3.3.5 When the materials, semi-finished products and finished products approach the
construction site, their specifications, models, appearance and quality certificates
shall be inspected in accordance with the relevant requirements of the current
national standard "Code for Acceptance of Constructional Quality of Concrete
Structures" (GB 50204).
3.3.6 After approaching the construction site, the materials shall be stored and
stacked separately as the types, specifications and batches, and marked clearly.
4 Formwork
4.1 General Requirements
4.1.1 Special construction scheme shall be prepared for the formwork. Technology
demonstration shall be carried out for the special construction schemes of tall
formwork support and such tool-type formwork as sliding formwork and creeping
formwork.
4.1.2 Formwork and support shall be designed to have adequate bearing
capacity and rigidity and ensure the overall stability according to various
operating conditions during the construction.
4.1.3 Formwork and support shall ensure the accuracy of the shape, dimension and
position of the structure and member, which shall also be convenient for the
reinforcement installation and concrete placing and maintenance.
4.2 Materials
4.2.1 Technical indexes of formwork and support materials shall meet the
requirements of the current relevant standards of the Nation.
4.2.2 Light-weight, high-strength and durable materials should be used in the
formwork and support. The standard approved products should be selected as the
connection.
4.2.3 The formwork exposed to concrete shall be smooth on the surface and shall
have good abrasion resistance and hardness. The panel materials of fair-faced
concrete formwork shall be able to ensure the required facing effect after formwork
stripping.
4.2.4 Release agent shall be able to reduce the adsorptive power between concrete
and formwork in an effective way, have certain film formation strength, and shall not
affect the later-stage decoration on the concrete surface after formwork stripping.
4.3 Design
4.3.1 Types and construction of formwork and support shall be determined according
to such conditions as engineering structure type, load, subsoil category, construction
equipment and material supply.
4.3.2 Formwork and support design shall include the following contents:
1 Model selection and structure design of formwork and support;
2 Load and its effect calculation on the formwork and support;
3 Checking for bearing capacity and rigidity of formwork and support;
4 Checking for overturning resistance of formwork and support;
5 Drawing of formwork and support construction drawing.
4.3.3 Formwork and support design shall meet the following requirements:
1 Limit states design method expressed by the partial coefficients should be adopted
in the structure design of formwork and support;
2 Calculation assumption and analysis model adopted in the structural analysis of
formwork and support shall be provided with theory or test basis, or proved feasible
through engineering verification;
3 Structural analysis shall be carried out for the formwork and support according to
various stressed operating conditions during construction, and the most unfavorable
action effect combination shall be determined;
4 Fundamental combination of loads shall be adopted for the calculation of bearing
capacity; only the characteristic value of permanent load may be adopted for the
deformation checking.
4.3.4 As for the design of formwork and support, the loads under different operating
conditions and their combinations shall be calculated according to the actual
conditions. Characteristic value of each load may be determined according to
Appendix A of this Code.
4.3.5 Bearing capacity of structural member of formwork and support shall be
calculated according to the temporary design conditions. Calculation of bearing
capacity shall meet the requirements of the following formula:
RS  0 …………………………………………………. (4.3.5)
Where,
0 -- Significance coefficient of structure, which should be 0 ≥1.0 for the important
formwork and support and shall be 0 ≥0.9 for the ordinary formwork and support;
coupler on the top, the bearing capacity of upright tube shall be checked according to
the eccentric distance not less than 50mm; the bearing capacity of upright tube in tall
formwork support shall be...