GB 16726-1997 Reinforced concrete span beams and deep beams GB16726-1997
Some standard content:
National Standard of the People's Republic of China
Reinforced concrete horizontal beam and longitudinal beam1Subject content and scope of application
GB 16726-1997
This standard specifies the specification size and model compilation method, technical requirements, test methods, inspection rules, marking, stacking and transportation of prefabricated reinforced concrete horizontal beam and longitudinal beam (hereinafter referred to as beam). This standard is applicable to beams of general civil and industrial buildings. For beams in corrosive environments, with surface temperatures above 100℃ or surface temperatures often above 60℃, and those affected by vibration, the relevant current national standards and specifications shall still be observed.
2 Reference standards
GB 175
Portland cement, ordinary Portland cement
GB700 Carbon structural steel
GB1344 Slag Portland cement, pozzolanic Portland cement and fly ash Portland cement Hot-rolled ribbed steel bars for reinforced concrete
GB1499
Hot-rolled round steel bars for reinforced concrete
GB13013
JB13014
Preheated ribbed steel bars for reinforced concreteGB/T14684 Sand for construction
GB/T 14685
Pebble and crushed stone for building
Code for construction and acceptance of concrete structure engineering GB50204
GBJ81Test method for mechanical properties of ordinary concreteTest and evaluation standard for concrete strength
GBJ107
GB J119
GB J321
Technical specification for application of concrete admixtures
Quality inspection and evaluation standard for precast concrete componentsQuality standard and test method for concrete water reducer JGJ56
Standard for water for concrete mixing
Technical code for application of 400MPa grade II steel bars in concrete structures YB 9072
3 Specifications, dimensions and model compilation method
3.1 The main specifications and dimensions of beams shall be adopted according to Table 1. Approved by the State Administration of Technical Supervision on January 19, 1997, and implemented on August 1, 1997
Height, mmWidth, mm
Span beam
Deep beam
GB 16726—1997
Main specifications and dimensions of beams
Marked length, m
Note: Width refers to the width of the web.
3.2 Beams are divided into span beams and deep beams. Span beams are divided into four cross-sections: rectangular, flat rectangular, small cantilever and large cantilever. Deep beams are divided into three cross-sections: rectangular, basket-shaped and T-shaped.
3.3 The model of a beam consists of a name, code, characteristic code, main parameter code and modification code. The representation is shown in Figure 1. 3.4 Model Example
The model of the reinforced concrete span beam with a marking length of 3.0m, a height of 240mm, a width of 240mm and a load level of 2 is KLA30-2.
4 Technical Requirements
Remodel Code
Main Parameter Code (marked length × 10; load level)-Characteristic Code (rectangular A; flat rectangular B; small cantilever C; large cantilever D; basket-shaped E; T-shaped F) Name Code (span beam KL; deep beam SI) Figure 1 Model Representation of Beams
4.1 Beams shall be produced in accordance with the provisions of this standard and the design drawings approved by the prescribed procedures, and the difference between their production length and the marked length shall meet the requirements of the design drawings.
4.2 Materials
4.2.1 Concrete
The quality of raw materials for concrete shall comply with the provisions of GB175, GB1344, GB/T14684, GB/T14685, JGJ56, JGJ63, GB119, etc.
4.2.2 Steel
4.2.2.1 The main reinforcement shall be Grade I steel, Grade I steel or 400MPa Grade B steel, and the rest shall be Grade 1 steel. The material shall comply with the provisions of GB1499, GB13013 and YB9072. 4.2.2.2 The hook shall be made of Grade 1 steel, and cold processing of steel is strictly prohibited. The embedded steel plate shall be made of No. 3 steel, and the material shall comply with the provisions of GB13013 and GB700.
4.2.2.3 Steel bars and embedded steel plates should have factory quality certificates and factory test reports, and should be stacked strictly according to steel grades and specifications, and should not be mixed up. At the same time, they should be prevented from rust and pollution. 62
4.3 Concrete strength
GB16726—1997
4.3.1 When the marking length is less than 5.4m, the concrete strength grade should not be lower than C20, and when it is greater than 5.4m, it should not be lower than C30. 4.3.2 The concrete strength grade of the beam shall meet the design requirements before installation. 4.4 Structural requirements
4.4.1 Beams used in seismic areas should consider structural requirements. 4.4.2 The concrete cover of the main reinforcement shall meet the requirements of the design drawings and shall not be less than 25mm, and its end shall not be less than 20mm. 4.4.3 The location and number of main reinforcement joints shall comply with the provisions of GB50204. 4.5 The manufacturing process of the beam shall comply with the relevant provisions of GB50204. 4.6
The appearance quality of the beam shall comply with the provisions of Table 2. Table 2 Appearance quality of the beam
Any part
Main force-bearing part
Secondary force-bearing part
Cracks that affect structural performance and use
Minor cracks that do not affect structural performance and use Appearance defects
Appearance stains
Appearance defects
Exposed reinforcement refers to the defect that the steel bars in the beam are not wrapped by concrete and are exposed. 2
Hole refers to the hole in the concrete whose depth and length exceed the thickness of the protective layer. Honeycomb refers to the defect that the concrete surface lacks cement mortar and forms exposed stones. 3
Cracks refer to gaps that extend into the concrete.
5 Appearance defects refer to the roughness, peeling, sanding and missing smearing on the beam surface. 6 Appearance stains refer to the presence of oil or sticky debris on the surface of the component. Quality requirements
Should not have
Total exposed length not exceeding 500mm
Should not have
Should not have
Total area not exceeding 1% of the component surface area, and each location not exceeding 0.01m2
Should not have
Should not have
Should not have
Should not have
Should not have
Should not have
7 Appearance defects refer to beam ends that are not straight, tilted, missing edges and corners, flash and convex rib scars. 4.7
The allowable deviations of the beam dimensions and related requirements shall comply with the provisions of Table 3. Table 3 Allowable deviations of the beam dimensions and related requirements Item number
Allowable deviation
+10,—5
Embedded reinforcement
Note: L is the beam length.
Lateral bending
Surface flatness
GB 16726—1997
Table 3 (end)
Center position deviation
Flatness with concrete surface
Main reinforcement protection layer
Allowable deviation
L/750 and less than 20
+10,-5
4.8 The structural performance of the beam, including bearing capacity, deflection and crack width, shall be tested, and the results shall comply with the requirements of the design drawings and the provisions of GBJ321.
5 Test methods
5.1 The test items and test methods of various raw materials shall comply with the provisions of the relevant current national standards. 5.2 The concrete strength test and evaluation shall comply with the provisions of GBJ107, and the test methods shall comply with the provisions of GBJ81. 5.3 The test methods of structural performance shall comply with the provisions of Appendix 2 of GBJ321 and the design drawings. The test parameters and inspection indicators are given by the design drawings according to the provisions of Appendix 1 of GBJ321. The appearance quality inspection method shall be carried out in accordance with the provisions of Table 4. 5.4
Table 4 Appearance quality inspection method
Any part
Main stress-bearing part
Secondary stress-bearing part
Cracks affecting structural performance and use
A small number of cracks that do not affect structural performance and use Surface defects
Surface stain
Appearance defects
5 The inspection method for appearance dimensions and related requirements shall be carried out in accordance with the provisions of Table 5. 5.5
Inspection method
Observation, measurement with a ruler
Observation and measurement with a ruler and a scale magnifying glass
Embedded parts dowel bars
6 Inspection rules
6.1 Factory inspection
GB 16726-1997
Table 5 Dimensions and related requirements Test methods Item
Lateral bending
Surface flatness
Center position deviation
Smoothness with concrete surface
Main reinforcement protection layer
Testing method
Measure with a ruler any part parallel to the length direction of the beamMeasure with a ruler any part perpendicular to the length direction of the beamBearing wires measure with a rulerMaximum value of lateral bending
Measure the maximum gap between the ruler and two points on the beam surface with a 2″ ruler and a wedge-shaped feeler gaugeMeasure the center line in the longitudinal and transverse directions with a ruler, whichever is greaterMeasure with a flat ruler and a steel plate ruler
Measure with a ruler or with a steel plate rulerThickness of reinforcement protection layer 6.1.1 Inspection items measured by measuring instrument mainly include steel bar material, concrete strength, appearance quality of beams, external dimensions and structural performance. 6.1.2 Inspection batch, sampling quantity, inspection and re-inspection rules, etc. shall comply with the provisions of GBJ321. 6.2 Type inspection
is an inspection to comprehensively assess product quality. 6.2.1 Inspection conditions
Type inspection should be carried out when one of the following situations occurs. a.
When the product is put into production for the first time for trial production and appraisal; when the product is transferred to another factory for production;
When the product is discontinued for more than half a year and then resumed; when there are major changes in design, process and materials that may affect product performance; when there are significant differences between the factory inspection results and the last type inspection results; during normal production Periodic inspection;
When the superior quality supervision and inspection agency makes an inspection request. 6.2.2 Inspection items
Inspect each item one by one according to the technical requirements of this standard. 6.2.3 Determine the inspection batch according to the requirements of the inspection conditions. Measure the appearance quality and external dimensions piece by piece or randomly sample 5% and no less than 3 pieces according to the inspection batch; determine the number of structural performance inspections according to the inspection conditions, and the inspection and re-inspection rules shall be carried out in accordance with the requirements of GBJ321. 6.3 Result evaluation
6.3.1 The supplier's quality supervision and inspection department shall inspect the beams according to this standard and relevant standards. 6.3.2 The factory inspection and evaluation shall comply with the provisions of GBJ321. 6.3.3 The type inspection results are qualified when they meet the technical requirements of this standard. . 7 Marking, stacking and transportation
7.1 The beams shall be marked with permanent markings, including: manufacturer name or trademark;
model;
GB16726-1997
production date (year, month, day) and production team; c.
inspection pass stamp.
7.2 Stacking and transportation
7.2.1 The beams shall be stacked according to model, quality grade, variety and production date, and lateral support shall be added to ensure the stability of the beams. The supporting position of the beams during stacking shall be consistent with the stress conditions of the beams, and pads shall be set at both ends. The pads shall be aligned up and down and leveled. 7.2.2
7.2.3 The stacking site shall be flat and compacted, and the number of stacking layers shall not exceed three. The supporting position and method of the beams during shipment shall be consistent with the stress conditions of the beams and shall be firmly fixed. 7.2.4
7.2.5 The anchor bars at the ends of the beams and the protruding steel bars of the surface anchor bars shall not be bent arbitrarily. 8 Product certificate
A product certificate shall be issued when the beam leaves the factory. The certificate shall include the following contents: a.
Certificate number;www.bzxz.net
Enterprise grade certificate number;
Standard drawing and design drawing number adopted;
Manufacturer name, trademark and year and month of production; model, specification and quantity,
Evaluation results of mechanical properties of concrete and main bars; Appearance quality and specification size inspection and evaluation results; Structural performance inspection and evaluation results;
Seal of the inspection department.
Additional notes:
This standard is proposed by the Ministry of Construction of the People's Republic of China. This standard is under the jurisdiction of the China Building Standard Design Institute, the technical unit of the Ministry of Construction for building structural components. This standard is drafted by the Professional Design Institute of the Ministry of Railways. The main drafters are Jiang Qizhou and Cao Dengjing.
This standard is entrusted to the China Building Standard Design Institute for interpretation.
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