Calculation of the reinforcement of the prefabricated slab, the calculation formula of the reinforce

It is not difficult to calculate the rebar cutting, and you will not be very worried.

The blanking length of the beam plate reinforcement = the axis size of the beam plate - the protective layer (generally 25) + the upper bending hook size 180 degrees bending hook = 6 25d

90 degree hook 3 5d

45 degree hook 4 9d

Re-salting to measure the difference: 30 degrees take 0 3d 45 degrees 0 5d 60 degrees 1d 90 degrees 2d 135 degrees 3d

If it is a general construction drawing, according to the above method, it is calculated on the right, such as the distribution of the plate, the longitudinal stress rib of the negative disc beam, and the frame rib. If it is a flat construction drawing, then refer to 03G101-1B.

The length of the stirrup, the outer length + the length of the hook - 6d

The length of the hook is 6 plus 100 8 plus 120 10 plus 140 stirrups = the length of the beam member - (25 protective layer) * 2 stirrup spacing + 1 gives you a software to calculate the length of steel bar cutting.

Hope satisfied!

This force is a bit big, you must match the steel bar according to the beam type, you make a section of 300 * 300, the lower part of the main steel bar 3 20, the upper part of 2 14, stirrups 6mm of 150 on it.

1. When marking the number and type of prefabricated panels, do not use the form of diagonals. Because this method is easy to cause the intersection of lines, it is advisable to use the method of horizontal lines or vertical lines, and the room type number of the same type is directly marked. The whole building should be numbered uniformly, which can reduce the design workload and facilitate the construction personnel to see the drawings.

2. The plate seam should be 40 as far as possible, and this kind of plate seam can not be equipped with reinforcement or add a rib.

When laying out the board, lay the board from the inside of the room to the outside, try to use a wide board, and leave the cast-in-place board belt near the window, and the width of the cast-in-place board should be 200 (consider the riser plate of plumbing).

3. If the structure requires a whole pouring layer, the plate joint should be greater than 60. The thickness of the whole pouring layer is 50, with two-way 6@250, concrete C20. Pure frame structures generally do not require the addition of a whole pouring layer.

4. Prefabricated slabs shall not be laid at the structural columns.

5. Prefabricated panels are not available in the underground garage due to fire prevention requirements.

6. The frame structure should not use the long-facing plate, otherwise the long-facing plate and the frame beam are prone to cracks at the parallel junction.

The calculation formula of the reinforcement of the slab is as=m (, reinforcement refers to the operation process of setting reinforcement in concrete and designing, processing and configuring it in order to enhance the bearing capacity of concrete. Natural.

The shrinkage creep of low-reinforced high-strength and high-performance concrete shows the characteristics of rapid development in the early stage and slow development in the later stage, which is consistent with the development law of concrete shrinkage and creep.

The shrinkage creep of reinforced concrete is smaller than that of plain concrete.

contraction creep. When the reinforcement ratio.

When it is low, its influence on shrinkage creep is small, and in engineering applications, it can be treated as plain concrete; When the reinforcement ratio is high, its effect on shrinkage creep needs to be studied in detail. Through the finite element analysis of reinforced concrete and the comparison with the test results, it can be concluded that the effect of creep should be considered in the analysis of the shrinkage strain of reinforced concrete, and ignoring the effect of creep will produce a large cavity error on the shrinkage strain. The higher the reinforcement ratio, the smaller the creep, and the creep of concrete under different loading ages is similar under the same reinforcement conditions.

The specifications for the reinforcement ratio requirements of the slab are: "Code for Design of Concrete Structures" GB50010-2010 (2015 Edition), "Technical Regulations for Concrete Structures of High-rise Buildings" JGJ3-2010, and the specific provisions are as follows:

1. Article 1 of the Code for the Design of Concrete Structures stipulates that the minimum reinforcement ratio of the tensile reinforcement in the concrete slab lying on the foundation can be appropriately reduced, but it should not be less than.

2. Article 1 of the Code for Design of Concrete Structures stipulates that when designing according to the one-way slab, the distribution of steel bars should be arranged in the direction perpendicular to the direction of stress, and the reinforcement on the unit width should not be less than 15% of the stressed steel bars on the unit width, and the reinforcement ratio should not be less than.

3. Article 1 of the Code for Design of Concrete Structures stipulates that in the area of cast-in-situ slab with large temperature and shrinkage stress, anti-cracking structural steel bars should be configured on the surface of the slab in both directions. The reinforcement ratio should not be less than 200mm, and the spacing should not be greater than 200mm.

4. Article 1 of the Technical Regulations for Concrete Structures of High-rise Buildings stipulates that the top floor of the basement floor as the embedded part of the superstructure should be made of beam and plate structure, and the thickness of the floor slab should not be less than 180mm, and the double-layer two-way reinforcement should be used, and the reinforcement ratio of each direction of each floor should not be less than.

5. Article 1 of the "Technical Regulations for Concrete Structures of High-rise Buildings" stipulates that the floor slab of the multi-tower structure and the body type retracted and cantilevered structure, and the vertical body shape mutation part should be strengthened, the thickness of the floor slab should not be less than 150mm, and the two-way reinforcement should be double-layered, and the reinforcement ratio of the reinforcement mesh in each direction of each layer should not be less than. Structural measures should also be strengthened for the floor slabs of the upper and lower structures at the site of body shape mutation.

12 thick cast-in-situ floor slab reinforcement method first bench:

1. The thickness of the plate is generally taken or these sizes. Try to use secondary steel including secondary steel with a diameter of 10, a stressed steel bar with a diameter of 12, except for the hook, shall not use primary steel.

2. The steel bar should have a large diameter and large spacing, but the spacing should not be greater than 200, and the spacing should be 200 as much as possible.

3. (The cracks of the plate with a general span of less than meters can meet the requirements) The upper steel bar of the plate with a span of less than 2 meters does not have to be disconnected, and the steel bar can not be drawn, which only means that the steel bar is a two-way double row 8*200.

4. The spacing between the upper and lower steel bars of the plate should be equal, and the diameters can be different, but the diameter types of steel bars should not be too much.

5. When the top layer and considering the crack resistance, the upper reinforcement of the plate can be continuous, or 50% connected, and the additional reinforcement and the tensile reinforcement should be connected according to the tensile lap reinforcement. When the plate reinforcement is the same, only the publication number can be marked.

Summary. The cast-in-place floor slab reinforcement should be determined according to the thickness of the floor slab to determine the size of the steel bar, the general cast-in-place floor slab can choose 120 mm, then at least the diameter of 10 mm of secondary steel needs to be selected, the thickness of the cast-in-place floor slab can also be selected 140 mm or 160 mm, depending on the specific requirements of the building. Basically, the diameter of the steel bar must be greater than 10 mm, and the spacing between each steel bar cannot be greater than 200 mm, and it can be set at about 200 mm as much as possible.

If the span of the floor slab is more than two meters, it is necessary to set up a double row of reinforcement, and the diameter of the double row of reinforcement should be at least 8 mm.

What is the reinforcement of the secondary prefabricated slab floor.

Cast-in-place floor slab reinforcement should be determined according to the thickness of the floor slab to determine the size of the steel bar, the general cast-in-place floor slab can choose 120 mm, then at least need to choose a diameter of 10 mm of the two quick finger grade steel, the thickness of the cast-in-place floor slab can also be selected 140 mm or 160 mm, depending on the specific requirements of the building. Basically, the diameter of the steel bar must be greater than 10 mm, and the spacing between each steel bar cannot be greater than 200 mm, and it can be set at about 200 mm as much as possible. If the span of the floor slab is more than two meters, it is necessary to set up a double row of steel bars for the first time, and the diameter of the double row of steel bars must reach at least 8 mm.

Repentance. I asked about the prefabricated floor slabs, how many reinforcements are for the secondary slabs.

It must be matched with steel bars according to the beam type, you do a section of 300 * 300 in the history of the world, 3 20 in the lower part of the main steel bar, 2 14 in the upper part, and 150 in the stirrup 6mm.

The prefabricated floor slabs are 3100x600x120 thick, with several cold-drawn bars per slab.

You can use 6-8mm main reinforcement to cold-draw 6.

According to the design diagram, the size is calculated by volume, unit: m3. Without deducting the volume of steel bars and embedded iron parts in the component, the beam head and beam pad extending into the wall are incorporated into the beam volume.

Cast-in-place concrete beam length regulations.

1) When the beam is connected with the column, the beam length is calculated to the side of the column; See diagram below.

2) When the main beam is connected with the secondary beam, the length of the secondary beam is calculated to the side of the main beam. See diagram below.

1. The engineering quantity of cast-in-place concrete and reinforced concrete formwork shall be calculated by 2 meters according to the area of the contact surface between concrete and formwork.

2, that is, the height between the outdoor floor to the bottom of the plate or the surface of the plate to the bottom of the plate shall prevail within meters, and the part above 3 or 6 meters shall be calculated according to the excess part to increase the amount of support engineering.

Jujube pants 3, cast-in-place reinforced concrete wall, hole with a single hole area within square meters, no deduction, no increase in the side wall of the hole. A deduction should be made when the area of a single hole is more than square meters.

4. The cast-in-situ reinforced concrete frame is calculated according to the relevant provisions of beams, plates, columns and walls, and the engineering quantity is calculated in the wall.

5. The overlapping parts connected by columns and beams, columns and walls, beams and beams, as well as the beam heads and plate heads that extend into the wall, are not calculated as formwork areas.

6. The exposed surface of the structural column should be calculated according to the exposed part of the formwork area. The contact surface between the structural column and the wall is not calculated for the formwork area.

7. The concrete step does not include the ladder belt, and the horizontal area of the step size is calculated, and the formwork area is not calculated on both sides of the step end.

8. The bench is dismantled and simplified cast-in-situ concrete small pool tank is calculated according to the peripheral volume of the component, and the formwork in the pool tank, outside and bottom is not calculated separately.