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GB 50666-2011 (GB50666-2011)

GB 50666-2011_English: PDF (GB50666-2011)
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BASIC DATA
Standard ID GB 50666-2011 (GB50666-2011)
Description (Translated English) Code for construction of concrete structures
Sector / Industry National Standard
Classification of Chinese Standard P25
Classification of International Standard 91.080.40
Word Count Estimation 221,258
Date of Issue 2011-07-29
Date of Implementation 2012-08-01
Quoted Standard GB 50007; GB 50009; GB 50010; GB/T 50080; GB/T 50081; GB/T 50107; GB 50119; GB 50204; GB/T 50476; GB/T 9142; GB 10171; GB 12523; GB/T 14370; GB 14902; GB/T 25182; JGJ 18; JGJ 55; JGJ 63; JGJ 85; JGJ/T 104; JGJ 107; JGJ 128; JGJ 130; JGJ 206; JGJ 256
Drafting Organization China Academy of Building Research
Regulation (derived from) Bulletin of the Ministry of Housing and Urban No. 1110
Summary This Chinese standard applies to the construction of concrete structures, does not apply to special lightweight aggregate concrete and concrete construction.

Standards related to: GB 50666-2011

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 checked according to the eccentric distance not less than
100mm;
4 The bearing capacity of the top horizontal tube supporting the formwork may be
checked according to the flexural member;
5 The anti-sliding bearing capacity of coupler may be checked according to the
relevant requirements of the current professional standard "Technical Code for Safety
of Steel Tubular Scaffold with Couplers in Construction" JGJ 130.
4.3.16 Where the support is erected with frame type, bowl-coupler type, disk lock type
or pin-on-disk type of steel tubular scaffolds, the central load transfer mode by
inserting the support column tube end into the base jack shall be adopted, the bearing
capacity and rigidity of the support may be checked according to the requirements of
the current relevant standards of the Nation.
4.4 Fabrication and Installation
4.4.1 Formworks shall be processed and fabricated according to the drawings.
Strongly-universal formworks should be fabricated into the approved ones.
4.4.2 Formwork panel walings should have uniform section height. During the
fabrication and installation of formwork, the panels shall be spliced tightly. As for the
walls with water-proof requirements, water-stop, which shall be connected with split
bolt by circumference welding, shall be arranged in the middle of formwork split bolt.
4.4.3 The special support matching with the universal steel pipe support shall be
processed and fabricated according to the drawings. The girder placed on the base
jack on the top of support may be made of batten, timber beam or section steel with
symmetrical sections.
4.4.4 Support column and vertical formwork, when installed on the soil layer, shall
meet the following requirements:
1 Subplates with sufficient strength and bearing area shall be arranged;
2 The soil layer shall be solid and provided with drainage measures; as for the
collapsible loess and expansive soil, waterproof measures shall be provided; as for
the frost heaving soil, frost heaving prevention measures shall be provided;
3 As for the soft subgrade, the preloading method may be adopted, if necessary, to
adjust the installation height of formwork panel.
included angle between diagonal bracing and horizontal tube should be 45° ~ 60°.
When the support height is greater than 3 times of the lift height, one horizontal
diagonal bracing should be arranged on the top of support and the diagonal bracing
shall be extended to the surroundings.
6 Splicing length of upright tube, horizontal tube and diagonal bracing shall not be less
than 0.8m and they shall be connected with at least 2 couplers; the distance from the
edge of coupler cover plate to the tube end shall not be less than 100mm.
7 Tightening torque of coupler bolt shall not be less than 40Nꞏm and shall not be
greater than 65Nꞏm.
8 Erecting vertical deviation of support upright tube should not be greater than 1/200.
4.4.8 Where the coupler type steel pipe is used as the tall formwork support, the
erection of support shall not only comply with Article 4.4.7 of this Code but also meet
the following requirements:
1 Base jack should be inserted on the top of support upright tube; the outer diameter
of base jack screw shall not be less than 36mm; the length of screw inserted into the
steel pipe shall not be less than 150mm and that of screw out of steel pipe shall not be
greater than 300mm; the cantilever length of base jack out of top horizontal tube shall
not be greater than 500 mm;
2 Longitudinal spacing of upright tube and transverse spacing of upright tube shall not
be greater than 1.2m; support lift height shall not be greater than 1.8m;
3 Where splicing is adopted within the top lift height of upright tube, the splicing length
shall not be less than 1m and they shall be connected with at least 3 couplers;
4 Bottom horizontal tube should be arranged on the longitudinal and transverse
directions of upright tube; the distance from the longitudinal bottom horizontal tube to
the bottom of upright tube should not be greater than 200mm;
5 The longitudinal or transverse vertical diagonal bracing should be arranged in the
middle; the spacing between diagonal bracing should not be greater than 5m; the
spacing between the horizontal diagonal bracing erected along the height direction of
support should not be greater than 6m;
6 Erecting vertical deviation of upright tube should not be greater than 1/200 and
should not be greater than 100mm;
7 Overall stability of support shall be strengthened by the effective connecting
measures which are taken according to the peripheral structure conditions.
4.5.7 The formwork and support member removed shall not be thrown, but stacked in
the designated place in a scattered way and timely cleared and transported.
4.5.8 After formwork removal, the surface of the member shall be cleaned, and the
deformation and damage positions shall be repaired.
4.6 Quality Control
4.6.1 Site inspection of member and connection of formwork and support shall meet
the following requirements:
1 Formwork surface shall be smooth; cementing layer of plywood formwork shall be
free from degumming or warped corners; support members shall straight and even,
free from severe deformation and rusting; connection shall be free from severe
deformation and rusting, as well as cracks;
2 Specification and dimension of formwork, diameter and wall thickness of support
member, and quality of connection, shall meet the design requirements;
3 As for the formwork assembled at the construction site, the appearance and
dimension of the component shall meet the design requirements;
4 If necessary, sampling inspection shall be carried out for the mechanical properties
of member and connection of formwork and support;
5 Appearance quality shall be inspected totally when they approaching the
construction site and before turnover.
4.6.2 Dimension deviation shall be inspected for the formwork after installation. As for
the embedded parts and reserved holes fixed on the formwork, their quantity and
dimension shall be inspected.
4.6.3 Where the coupler type steel pipe is used as the formwork support, the quality
control shall meet the following requirements:
1 Deviation of spacing between support upright tubes below beam should not be
greater than 50mm; deviation of spacing between support upright tubes below slab
should not be greater than 100mm; deviation of spacing between horizontal tubes
should not be greater than 50mm.
2 As for the horizontal tube bearing the formwork loads on the top of support, the
quantity of couplers for connecting the horizontal tube and support upright tube shall
be checked. As for the anti-sliding coupler arranged in double-coupler structure, the
upper and lower couplers shall be against each other tightly, in the clearance not
5 Reinforcement
5.1 General Requirements
5.1.1 Reinforcement should adopt the fabricated steel bar produced in a specialized
way.
5.1.2 Reinforcement connection mode shall be selected according to the design
requirements and construction conditions.
5.1.3 When the reinforcement is required to be replaced, the design change
documents shall be transacted.
5.2 Materials
5.2.1 Properties of the reinforcement shall meet the requirements of the current
relevant standards of the Nation. Nominal diameter, nominal sectional area,
calculation sectional area and theoretical weight of common reinforcement shall meet
the requirements of Appendix B of this Code.
5.2.2 As for the structures with requirements for seismic resistance, the
properties of longitudinal stressed reinforcement shall meet the design
requirements; where there are no specific requirements in the design, as for the
frames and diagonal brace members (including stair-flight) designed according
to Aseismic Grade I, II and III, the common longitudinal stressed reinforcement
thereof shall adopt HRB335E, HRB400E, HRB500E, HRBF335E, HRBF400E or
HRBF500E, and its strength and measured value of total elongation under the
maximum force shall meet the following requirements:
1 The ratio of the measured value of tensile strength to that of yield strength of
reinforcement shall not be less than 1.25;
2 The ratio of the measured value of yield strength to the characteristic value of
yield strength of reinforcement shall not be greater than 1.30;
3 The total elongation of reinforcement under the maximum force shall not be
less than 9%.
5.2.3 During construction, measures shall be taken to prevent the confusion, rusting
or damage of reinforcement.
5.2.4 During construction, if there is brittle failure, poor welding performance or
5.3.5 The length of straight segment of bent longitudinal stressed reinforcement shall
meet the design requirements and the relevant requirements of the current national
standard "Code for Design of Concrete Structures" (GB 50010). Where the terminal of
plain round bar is made into 180° hook, the length of straight segment of bent hook
shall not be less than 3 times of the diameter of steel bar.
5.3.6 Terminals of stirrup and tie bar shall be made into hooks according to the design
requirements and shall meet the following requirements:
1 As for the general structural member, the bend angle of stirrup hook shall not be
less than 90° and the length of straight segment after bending shall not be less than 5
times of the diameter of stirrup. As for the structural member with requirements for
seismic resistance or special design requirements, the bend angle of stirrup hook
shall not be less than 135 ° and the length of straight segment after bending shall not
be less than 10 times of stirrup diameter or 75 mm, whichever is larger;
2 Splicing length of circular stirrup shall not be less than its tension anchorage length;
both terminals shall be made into the hooks not less than 135 °. The length of straight
segment after bending shall not be less than 5 times of the stirrup diameter for the
general structural member, which shall not be less than 10 times of stirrup diameter or
75mm, whichever is larger, for the structural member with requirements for seismic
resistance;
3 Where the tie bar is used as the one between single-leg stirrups or beam waist
stirrups in the beam and column compound stirrup, the bend angle of hooks at both
ends shall not be less than 135°, and the length of straight segment after bending
shall meet the relevant requirements of Item 1 of this Article for stirrups. Where the tie
bar is used as the one in such members as shear wall and floor slab, the hooks may
be made into 135° on one end and 90° on the other end, and the length of straight
segment after bending shall not be less than 5 times of the diameter of tie bar.
5.3.7 Flash butt welding should be adopted for welding sealed stirrup, besides gas
pressure welding or single welded lap joint may also be adopted. During the welding
process, the special equipment should be adopted. Fabrication length for welding
sealed stirrup and end socket fabrication shall be determined according to the welding
procedures. Welding points for welding sealed stirrup shall be arranged according to
the following requirements:
1 There shall be 1 welding point on each stirrup. The welding point should be in the
middle of some side of polygon stirrup. The distance between the welding point and
the stirrup bending point should not be less than 100mm;
2 Welding point of rectangular column stirrup should be arranged on the short side of
column; welding point of equilateral polygon column stirrup may be arranged on any
side; welding point of in-equilateral polygon column stirrup shall be arranged on
different sides;
reinforcement welder qualification test certificates and operate according to the scope
specified in the certificates.
2 Before the reinforcement welding construction, the welders involved in such welding
shall conduct the welding procedure test under the site conditions, who may start to
weld upon qualified test. During the process of welding, in the case of changing
designation and diameter of reinforcement, the welding procedure test shall be
carried out again. The materials, equipment, accessories and operational conditions
applied in the process test shall be consistent with those in the actual construction.
3 As for the fine grain hot-rolled steel bar and the ordinary hot-rolled steel bar with
diameter greater than 28mm, their welding parameters shall be determined after tests;
the remained heat treatment ribbed steel bars should not be welded.
4 Electro slag pressure welding shall be only applicable to the connection of vertical
stressed reinforcement in such members as column and wall.
5 Application scope, process requirements, electrodes and flux selection, welding
operation as well as quality requirements of welded joints of reinforcement shall meet
the relevant requirements of the current professional standard "Specification for
Welding and Acceptance of Reinforcing Steel Bars" JGJ 18.
5.4.4 Where the longitudinal stressed reinforcement adopts mechanical joints or
welded joints, the arrangement of joints shall meet the following requirements:
1 The joints set in the same member should be staggered in batches.
2 Joint connecting segment shall be 35d in length and shall not be less than 500 mm.
The joints whose midpoints are within the length of the above connecting segment
shall belong to the same connecting segment. In the length equation, d is the smaller
diameter of the two interconnected steel bars.
3 Within the same connecting segment, the joint area percentage of longitudinal
stressed reinforcement is the ratio of the sectional area of the longitudinal stressed
reinforcement with joints and that of all the longitudinal stressed reinforcement; the
joint area percentage of longitudinal stressed reinforcement shall meet the following
requirements:
1) As for the tension joint, is should not be greater than 50%; as for the
compression joint, it may be unrestricted;
2) As for the slab, wall and column, the mechanical tension joints may be
broadened according to the actual conditions; as for the precast concrete
structure, the tension joints at the member connection may be broadened
3) Where it is required to increase the joint area percentage: as for beam members,
it shall not be larger than 50%, as for other members, it may be broadened
properly according to the actual conditions.
5.4.6 As for such members as beam and column, stirrups shall be configured within
the splicing length range of their longitudinal stressed reinforcement according to the
design requirements, which shall meet the following requirements:
1 The stirrup diameter shall not be less than 25 % of the relatively large diameter of
the lapped bars;
2 The spacing between stirrups in the tensile splicing segments shall not be greater
than 5 times of the smaller diameter of the lapped bars and shall not be greater than
100mm;
3 The spacing between stirrups in the compressive splicing segments shall not be
greater than 10 times of the smaller diameter of the lapped bars and shall not be
greater than 200mm;
4 Where the diameter of the longitudinal stressed reinforcement in the column is
greater than 25mm, two sticks of stirrups shall be arranged respectively within the
range of 100mm outside of the two end faces of lap joint. The spacing between the
stirrups should be 50m.
5.4.7 The reinforcement binding shall meet the following requirements:
1 Binding lap joints of reinforcement shall be fastened with iron wires at the center and
both ends of the joints;
2 In the wall, column and joist steel framework, all the intersection points of
reinforcement mats on each vertical face shall be bound; all the intersection points of
reinforcement mat on the upper slab shall be bound; the intersection points of bottom
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