This standard specifies the specifications, technical requirements, test methods, inspection rules, product marking, transportation, and stacking of prestressed concrete thin plates for composite slabs. This standard applies to prestressed concrete thin plates for composite slabs in industrial and civil building floors and roofs. GB 16727-1997 Prestressed concrete thin plates for composite slabs GB16727-1997 GB16727-1997 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Precast prestressed concrete panel for composite slab
Precast prestressed concrete panel for composite slab1Subject content and scope of application
GB 16727 --- 1997
This standard specifies the specifications, technical requirements, test methods, inspection rules, product marking, transportation and stacking of precast prestressed concrete panels for composite slabs.
This standard applies to precast prestressed concrete panels for composite slabs in industrial and civil building floors and roofs. Structures in corrosive environments, with surface temperatures above 100°C, or with production heat sources and with surface temperatures often above 60°C, as well as panels affected by vibration, shall comply with the relevant current national specifications and regulations. 2 Reference standards
Concrete admixtures
GB 8076Www.bzxZ.net
Concrete structure engineering construction and acceptance code GB50204
GBJ16 Code for fire protection design of buildings
GBJ45 Code for fire protection design of high-rise civil buildings GBJ321 Standard for quality inspection and assessment of precast concrete components 3 Symbols
V: Design value of shear force of composite slab, N;
b: Width of composite slab section, mm;
h. : Effective height of composite slab section, mm;0con: Tension control stress, N/mm2,
fuk: Standard value of ultimate tensile strength of steel bar, N/mm2;gk: Weight of thin plate per extended meter;
M. : Mid-span bending moment when the thin plate is under its own weight and simply supported at both ends; Mer: Crack bending moment of the thin plate under tension concrete; Pr: External load calculated according to Me;
Pi, P2: External load.
4 Specifications and dimensions
4.1 The width of the unidirectional prestressed thin plate is mainly 900, 1200 and 1500mm, and 600, 1800, 2400mm and other specifications can be added when actually needed. However, the width selected by the standard drawing and the component factory should not exceed 3 types. 4.2 The short side span of the bidirectional prestressed thin plate is mainly 3300, 3600, 3900 and 4200mm, and its size can also be increased according to the three-molding system according to actual needs.
4.3 The specifications of the thin plate shall comply with the provisions of Table 1 and Table 2. Approved by the State Administration of Technical Supervision on January 19, 1997 and implemented on August 1, 1997
Types of prestressed tendons
Non-prestressed tendons
Concrete strength grade
Long side span, m
Thickness, mm
Short side span, m
Types of prestressed tendons
Non-prestressed tendons
Concrete grade
5 Classification marking
5.1 Product classification
GB 16727—1997
Unidirectional prestressed thin plate
Cold drawn low carbon steel wire
Cold drawn low alloy steel wire
900, 1200.1500
Notched steel wire
Grade B cold drawn low carbon steel wire, Grade I
C30, C40
Table 2 Bidirectional prestressed thin plate
3.33.63.94.2
Cold drawn low alloy steel wire, notched steel wire
Grade B cold drawn low carbon steel wire, Grade 1
The products can be divided into two categories according to the prestress configuration direction: unidirectional prestressed and bidirectional prestressed thin plates. 5.2 Marking and examples
5.2.1 Marking
The marking method of prestressed concrete thin slabs for composite slabs is expressed in the following format: Y-DB
5.2.2 Example
Plate serial number
Mark width
Mark length
Prestressed thin slab
GB16727-1997
The mark length is 3.6m, the mark width is 1.2m, and the prestressed concrete thin slab with slab serial number 1. Prestressed thin plate Y-DB3612-1GB16727--19976 Technical requirements
6.1 The concrete strength grade of the thin plate shall not be lower than C30. 6.2 Materials
6.2.1 Cold-drawn low-carbon steel wire, notched steel wire and cold-drawn low-carbon alloy steel wire are suitable for prestressed steel wire of thin plates. Smooth carbon steel wire is not allowed (see Table 1 and Table 2)
6.2.2 Ordinary Portland cement and Portland cement with a grade not lower than 425 should be used for cement. During steam curing, slag Portland cement with a grade not lower than 425 can also be used.
6.2.3 Medium sand should be used for sand, and crushed stone with a particle size of 5 to 20 mm should be used for coarse aggregate. 6.2.4 The performance of concrete admixtures shall comply with GB8076 and can only be used after being tested and meeting the requirements. It is strictly forbidden to add nitrogen salt admixtures. 6.3 Structural requirements
6.3.1 Prestressed steel wires should be evenly arranged in single or double rows along the width of the plate. The combined force point of the prestress should be set between the center of the thin plate section and 2.5mm below the center.
6.3.2 Prestressed steel wire protective layer thickness: when the thickness of the thin plate is 40mm, it shall not be less than 15mm; when the thickness of the thin plate is greater than or equal to 50mm, it shall not be less than 20mm.
6.3.3 The horizontal clear distance of prestressed steel wires should not be less than 25mm. 6.3.4 One-way prestressed thin plates should be equipped with transverse distribution bars, the spacing of which should not be greater than 300mm, and three densely distributed distribution bars arranged evenly in the transverse direction should be set within 100mm of the plate end.
6.3.5 Plate surface bonding steel bars
a. When the shear strength V/bh of the superimposed surface is greater than 0.4N/mm\, bonding steel bars should be added to the thin plate surface. b. The setting of the thin plate surface bonding steel bar shall meet the design requirements. Its lower half shall be buried in the thin plate concrete and tied with the prestressed steel wire. The height of the upper part exposed from the plate surface shall not be less than 2/3 of the thickness of the superimposed layer. The concrete protective layer of the bonding bar shall not be less than 10mm. 6. 3.6 Lifting rings
a. The lifting rings must be made of Grade 1 hot-rolled steel bars that have not been cold-drawn. Their diameter, quantity and position shall be prepared according to the design drawings, and the minimum diameter shall not be less than 8mm. The lifting ring design must meet the requirements of bearing capacity, crack resistance and deflection during lifting, demoulding, stacking, transportation, loading and unloading, and lifting.
b. There must be hooks at both ends of the lifting ring, the hook direction is upward, and it is anchored under the prestressed steel wire. The straight length of the anchor end shall not be less than 30 d (d————diameter of the lifting ring steel bar). 6.3.7 The embedded parts, reserved holes and prestressed steel wires extending from the ends of the thin plates shall meet the following requirements: a. The embedded parts and holes on the thin plates shall be set according to the design requirements, and non-prestressed reinforcement bars shall be set around the openings. The prestressed steel wires in the openings may not be cut off temporarily, and will be cut off when the equipment is installed after the concrete of the superimposed layer is poured. b. For thin plates with large openings, the position of the hanging points of the thin plates, the bearing capacity, crack resistance and deflection during construction shall be verified according to the position of the openings, and the position of the hanging points and reinforcement shall be adjusted. C. The length of the prestressed steel wire extending from the ends of the thin plates (including the prestressed steel wire on the other side of the bidirectional prestressed thin plates) and the length of the lateral distribution reinforcement extending shall meet the requirements of the design drawings and shall not be broken. 6.4 Construction process requirements
6.4.1 Thin plates should be made by the long-line pedestal pre-tensioning method or the steel mold external tensioning pre-tensioning method. 6.4.2 The tension control stress con of the prestressed steel wire shall meet the design requirements and should not exceed the following allowable values: 0.75fpki for notched steel wire, 0.7Fpk for cold-drawn low-alloy steel wire and 0.7Fpk for cold-drawn low-carbon steel wire. 6.4.3 When the super-tensioning method is used to reduce the relaxation loss of prestressed tendons, the tension control stress in 6.4.2 can be increased by 0.05fmk. The tensioning sequence and tensioning stress control method shall comply with the provisions of GB50204. 6.4.4 When the prestressed steel wire adopts the upsetting clamp, the head strength shall not be less than 90% of the standard value of the ultimate tensile strength of the steel wire. 6.4.5 The distribution reinforcement shall be tied to the prestressed steel wire or pre-spot welded into a mesh before installation. If there is no design requirement, the steel bars in the spot-welded mesh parallel to the prestressed steel wire only need to consider maintaining the mesh without deformation. 6.4.6 When prestressed steel wires are released, the compressive strength of the concrete cube must meet the design requirements. When there are no design requirements, it should not be lower than 75% of the designed concrete strength grade.
6.4.7 The order of releasing prestressed steel wires, when there are no design requirements, should be released symmetrically in batches and staggered. 6.4.8 The upper surface of the thin plate should be processed into a dense rough surface. When there is no bonding reinforcement on the surface, the difference in concave and convex should not be less than 4mm, and the technical requirements and inspection methods for the roughness of the surface of the thin plate should be indicated in the design drawing. 6.5 Quality requirements
6.5.1 When straightening the prestressed steel wires, if dead bends, splits, small thorns, sandwiches, necking, mechanical damage, iron oxide scale, and pits visible to the naked eye are found, they should be cut off.
6.5.2 Measures should be taken to prevent the prestressed steel wires from being contaminated by isolation agents. 6.5.3 The cutting length of prestressed steel wire shall be determined by calculation. When multiple steel wires are tensioned simultaneously using a head clamp, the relative difference in the effective length of the steel wires shall not exceed 1/5000 and shall not be greater than 5mm. For components with a length of no more than 6m, when the steel wires are tensioned in groups, the relative difference in the cutting length shall not be greater than 2mm.
6.5.4 The shrinkage of the prestressed steel wire at the tensioning end during the anchoring stage shall comply with the following provisions: 1mm for the head clamp;
5mm for the cone plug type and the clip type clamp.
6.5.5 The number of prestressed steel wires that are broken or slipped in the same direction shall not exceed 5% of the total number of steel wires, and it is strictly forbidden for two adjacent prestressed steel wires to break or slip. The broken or slipped steel wires must be replaced before pouring concrete. 6.5.6 When the prestressed steel wires of thin plates are released, the shrinkage value of the steel wires in the concrete should not be greater than 2mm. 6.5.7 The bottom of the thin plate should be smooth and straight. The allowable deviation of the flatness of the bottom of the plate is 4mm for the plate without ceiling and 5mm for the plate with ceiling. The method of checking the flatness of the bottom of the plate should be to check the production platform, not the thin plate directly. L is the long side of the thin plate. 6.5.8 The allowable deviation of the dimensions of each part of the thin plate shall comply with the provisions of Table 3. Table 3 Allowable deviation of the dimensions of each part of the thin plate
Diagonal
Lateral bending
Deflection (when the support point is at the lifting ring position)
Surface flatness
Board bottom smoothness
Allowable deviation
+10 -5
L/750 and ≤20
Prestressed steel wire
Protective layer
Extension length
Head diameter
Head thickness
Head center offset
GB 167271997
Table 3 (End)
Allowable deviation
Dimension requirements
0. 7 d~0. 9 d
6.5.9 Thin plates are not allowed to have cracks perpendicular to the direction of the prestressed steel wire. Bidirectional prestressed thin plates are not allowed to have cracks in both directions. When cracks parallel to the prestressed tendons appear in single prestressed thin plates, they should be handled according to the design requirements. However, mesh cracks, cracks and water lines are not limited to this. 6.5.10 Thin plates are not allowed to have honeycomb holes, rough surface at the bottom of the plate, sanding, peeling, missing tendons, loose plate ends, and hard damage and corner loss with an area greater than 50mm×50mm. When floating slurry is found on the upper surface, it must be brushed clean before leaving the factory. 7 Test methods
7.1 Mechanical properties test methods.
7.1.1 The comprehensive quality inspection of thin plate products should be carried out by testing the crack resistance of the normal section, and the test should be carried out when the thin plate concrete reaches the design strength grade (28d age).
7.1.2 The test adopts the method of adding concentrated load to single span simply supported (Figure 1a) or symmetrical double cantilever single span simply supported (Figure 1b), or the method of adding uniformly distributed load can also be adopted.
a. Simple diagram of single span simply supported test
b. Simple diagram of symmetrical double cantilever single span simply supported test Figure 1
7.1.3 When M≤95%M, the test method shown in Figure 1a is adopted, and when M.95%M, the test method shown in Figure 1b is adopted. In Figure 1b, L and L are the support spacings determined when the mid-span bending moment is equal to 95%M when LL/2. 7.1.4 Test steps
Loading sequence
The first load is Pt,P,=95%Pr;
The second load is P2,P,=5%Psr.
GB16727-1997
P, loading is divided into five times, P2 is loaded once, and the duration of each level of loading shall comply with the provisions of GBJ321. 7.1.5 In Articles 7.1.2 to 7.1.4, the values ​​of a, b, L, Ls, Per, Mcr, and M. shall be given by standard drawings or provided by designers. 7.2 The fire protection requirements of thin plates shall comply with the relevant provisions of GBJ16 and GBJ45. 7.3 The fire resistance level shall be controlled by the thickness of the concrete protective layer of the prestressed steel wire of the thin plate, and it can also be controlled by building fireproof materials. 8 Inspection rules
8.1 The technical inspection department of the thin plate manufacturer shall inspect the material properties, appearance quality, dimensional deviation, prestressing tension and mechanical properties of the thin plate. Those that meet the technical requirements of this standard shall be qualified products. 8.2 Material performance inspection
8.2.1 All steel products shall have a manufacturer's product certificate and inspection report. The sheet manufacturer shall conduct re-inspection in accordance with the provisions of GB50204 and shall have a re-inspection report.
8.2.2 Concrete strength inspection In addition to the test blocks made with standard curing in accordance with the provisions of GB50204, each work shift shall take two groups of test blocks cured under the same conditions, one group to test the concrete strength grade when the prestressed steel wire is released, and the other group can be used as a spare or to test the concrete strength grade of the sheet when it leaves the factory.
8.3 All sheets shall be inspected for appearance quality. 8.4 Dimension inspection shall be carried out by spot checking 5% of the number of products of the same type, but not less than 3 pieces. If there is one unqualified piece, double sampling inspection shall be carried out. If there are still unqualified ones, they must be inspected piece by piece. 8.5 Inspection of appearance and dimensional allowable deviation (Table 3) The method shall meet the following requirements: 8.5.1 Length inspection shall be measured with a steel ruler with an accuracy of 1mm. 8.5.2 The flatness of the bottom of the plate is checked with a 2m long ruler and a wedge-shaped feeler gauge with an accuracy of 0.5mm. 8.5.3 The lateral bending is measured with a tension wire (diameter less than 0.5mm) and a wedge-shaped feeler gauge with an accuracy of 0.5mm. 8.6 To determine the retraction value of the prestressed steel wire into the concrete when the prestressed steel wire is released and cut, two steel wires can be selected from the thin plate at both ends and the middle part of each pedestal. The test accuracy should be 0.5mm. The test method is to stick a glass sheet on the end of the plate, stick a colored tape on the steel wire, and use a vernier caliper to read and record.
8.7 Check the retraction value of the anchorage of the prestressed steel wire specified in 4.5.4. When the prestressed steel wire is pulled to the specified maximum tension, mark the steel wire and the corresponding pedestal platform at about 300mm away from the tensioning steel beam. After all anchors are completed, use a ruler to measure the relative displacement between the steel wire and the mark on the pedestal, i.e. the retraction value. Three points are randomly sampled at both ends of each production line and recorded. 8.8 Mechanical properties test rules
8.8.1 When 1000 pieces of the same type of thin plates are continuously produced according to the same process or the total number of pieces produced within 3 months is less than 1000 pieces, one piece should be randomly sampled for mechanical properties test.
8.8.2 In the first sampling test, when P%≥100%P., the tensile concrete at the bottom of the plate has not cracked, and the batch of thin plates is qualified; when P<95%Pe, the tensile concrete at the bottom of the plate has cracks, and the batch of thin plates is unqualified. 8.8.3 The results of the first sampling test show that when 95%P%≤Pe<100%P. r, the tensile concrete at the bottom of the plate has cracks, and 2 more thin plates can be sampled for inspection. When P%≥95%Per, no cracks were found in the tensile concrete at the bottom of the plate on the two thin plates, and the batch of thin plates is qualified. If the first thin plate sampled for the second time has no cracks in the tensile concrete at the bottom of the plate when P≥100%P., the thin plates are qualified. 9 Marking, factory certificate, lifting, stacking and transportation 9.1 Marking:
Each thin plate leaving the factory should be marked with the factory name or factory logo, project name, thin plate model, concrete pouring date, production team and "qualified" sample in a conspicuous position.
9.2 Factory certificate
The factory certificate shall include the following contents:
Certificate number
Standard number
GB 16727-1997
Name of the manufacturer of the thin plate and the date of pouring concrete Component specifications and quantity
Concrete strength test and evaluation results
Signature of the quality inspection department
Appearance and size test and evaluation results
Type and specification of main reinforcement Mechanical property test and evaluation results Mechanical property test and evaluation results
Name of the entrusted production unit and the project or the number of the adopted atlasj
9.3 When the thin plate is demoulded and lifted, the force should be evenly hooked, and the angle between the lifting rope and the horizontal plane should be greater than 45°. When the design requires more than 4 lifting points for the thin plate, pulleys or special hangers must be added to ensure that all lifting points are evenly hooked. 9.4 The stacking site of thin plates should be compacted and have drainage measures, and water accumulation is not allowed. The bottom of the thin plate stack must be padded with full-length pads, and the cross-section of the pads should not be less than 100mm×100mm. The pads between thin plates are close to the lifting rings, their length should not be less than 300mm, and the cross-section should be greater than 50mm×50mm and must be higher than the lifting rings and reserved reinforcements on the board surface. The upper and lower pads must be aligned and padded. 9.5 Thin plates should be stacked according to specifications and models, and the number of stacking layers should not exceed 10. 9.6 The stacking time of thin plates should not exceed 2 months. 9.7 Thin plates should be loaded flat, and the requirements for pads are the same as 9.4. The loading height should not exceed 8 layers. They must be tied firmly and can also be transported upright when special measures are taken.
9.8 Thin plates should be lifted and placed gently when hoisted into place, and collision is strictly prohibited. When lifting more than 2 pieces at a time, the position of the bottom wire rope should be aligned with the position of the pads for the thin plates. Other requirements are the same as 9.3. In addition to the weight control, the number of thin plates lifted each time should not exceed 4. Additional notes:
This standard is proposed by the Ministry of Construction of the People's Republic of China. This standard is managed by the China Building Standard Design Institute, the technical management unit of building structural components standards of the Ministry of Construction. This standard was drafted by the China Building Standard Design Institute, Beijing Construction Engineering Corporation, Beijing Fifth Construction Engineering Corporation, Beijing Construction Engineering Design Company, and Beijing Construction Engineering Research Institute. The main drafters of this standard are Gu Taichang, Zhang Zhenhua, Guo Yucui, Mu Zengren, Li Zhihong, and Lin Yuanzheng. This standard is entrusted to the China Building Standard Design Institute for interpretation. 73
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