First, the construction preparation
(1) operating conditions
1. After the reinforcement comes into the site, check whether there is a factory material certificate and complete the second interview. According to the location specified in the construction plan, stow-wood shall be stacked separately according to the specifications, use parts and numbers.
2, steel binding before, should check whether there is rust, rust removal and then shipped to the binding site.
3. Be familiar with the drawings, and check whether the specifications, shapes and quantities of the processed steel bars are correct according to the design requirements.
4, to do a good job of pay-off, play a good level elevation lines, columns, wall dimension line.
5, according to play good skin dimension line, check the position, quantity, length of the lower reserved lap reinforcement, such as does not meet the requirements, should be processed. Before binding, according to 1: 6, straighten the overlapping steel bars protruding from the lower layer and remove dirt such as rust and cement mortar.
6. According to the elevation, check whether the elevation of the concrete surface (column top and wall top) where the lower layer extends out of the lap reinforcement meets the requirements of the drawings, and the concrete construction joints should be chiseled and cleaned.
7. Set up scaffolding as required.
(2) Material requirements
1. Raw materials of steel bar: supplier qualification certificate, ex-factory quality certificate of steel bar, mechanical performance re-inspection and witness sampling test as required. When special circumstances such as brittle fracture occur during processing, it is necessary to carry out chemical composition inspection. Steel bars shall be free of old rust and oil stain.
2. Molded steel bars: they must conform to the specifications, models, sizes, shapes and quantities of the ingredient list, and should be marked. Molded steel bars must be covered to prevent rust in the rain.
3. Iron wire: No.20 ~ No.22 iron wire (burnt wire) or galvanized iron wire (lead wire) can be used. The cutting length of iron wire should meet the use requirements.
4. Pad: made of cement mortar, 50mm square, with the same thickness as the protective layer, and 20 ~ 22 fire wires are embedded in the pad. Or use plastic cards, braces, and support rods.
(3) Instruments and tools
Steel hook, crowbar, wrench, binding frame, wire brush, trolley, chalk, ruler, etc.
Second, the quality requirements
Note: See the corresponding part of "Technical Disclosure Record of Independent Column Foundation Engineering" for the specific requirements of reinforcement engineering.
Third, the process flow
1, column reinforcement binding:
Set of column stirrups → lap and bind vertical steel bars → draw stirrup spacing lines → bind stirrups.
2, shear wall reinforcement help binding
Erect 2-4 vertical bars-draw the spacing between horizontal bars-tie the horizontal bars-tie other horizontal bars and vertical bars.
3, beam steel binding
Draw the stirrup spacing between the primary and secondary beams-place stirrups between the primary and secondary beams-pass through the longitudinal bars at the bottom of the main beam and bend the bars-pass through the longitudinal bars at the bottom of the secondary beam and fix them with stirrups-bind them according to the stirrup spacing? —— Pass through the upper longitudinal reinforcement of the secondary beam —— Tie it according to the stirrup spacing.
4, plate steel binding
Clean the template-draw lines on the template-tie the reinforced bar under the plate-tie the negative bending moment reinforced bar.
5, stair steel binding
Draw position line-tie main reinforcement-tie local reinforcement-tie step reinforcement.
Fourth, the operation process
(A) column steel binding
1. Column stirrups: Calculate the number of stirrups for each column according to the spacing required by the drawings. First, put the stirrups on the lap bars protruding from the lower layer, and then tie the column bars at least three times within the lap length, and tie them in the center of the column. When the main reinforcement of the column is lapped with round steel, the corner hook is 450 with the formwork, and the middle steel hook is 900 with the formwork.
2. Lapping and binding of vertical reinforced bars: After the main reinforcement of the column is installed, the lap length of the joint should meet the design requirements. If there is no design requirement, it shall be adopted according to table 1.
Strength grade of top reinforced concrete
C20C25C30
1 Grade I steel bar 35d, 30d, 25d
Grade 2II reinforcement (crescent) 45d 40d 35d
3 Grade 3III rebar (crescent) 55d 50d 45d
note:
A. When grade I and II rebar D is d≥25mm or higher, the lap length shall be increased by 5d according to the values in the table.
B when the diameter of the threaded steel bar is less than or equal to ≤25mm, the lap length of the tensile steel bar shall be reduced by 5d according to the values in the table.
C in any case, the lap length shall not be less than 300mm. The positions of binding joints shall be staggered. From the center of any binding joint to 1.3 times the overlapping length, the percentage of the cross-sectional area of steel bars with binding joints to the total cross-sectional area of steel bars: the tensile area shall not exceed 25%; The compression zone shall not exceed 50%. When welded joints are used, from the center of any welded joint to the section with the length of 35 times the diameter of steel bar and not less than 500mm, the area of welded steel bar accounts for the percentage of the total area of steel bar: the tensile area should not exceed 50%; The compression zone is not limited.
3. When the vertical reinforcement of the column is connected by mechanical or welding, the joint position should be staggered by 50% according to the specification requirements, and the joint spacing between the upper and lower layers should be greater than 35d. The first step is that the joint is more than 500mm away from the floor surface, which is more than h/6, and it is not in the stirrup encryption area.
4. Draw the stirrup spacing line: draw the stirrup spacing line with chalk on the vertical bar of the column that has been erected.
5, column stirrup binding
(1) Move the set stirrup upward according to the stirrup position line, tie it from top to bottom, and tie it with the buckle, as shown in figure 1.
(2) Stirrup should be perpendicular to the main reinforcement, the intersection of stirrup corner and main reinforcement should be bound, and the intersection of main reinforcement and non-corner part of stirrup should be bound into a plum blossom shape.
(3) The hoops of stirrups are staggered along the vertical steel bars of the column and bound firmly, as shown in Figure 2.
(4) In areas with seismic requirements, the stirrup end of the column should be bent to 135 degrees, and the length of the straight part should not be less than 1Od(d is the stirrup diameter), as shown in Figure 3. When the stirrups overlap at 90 degrees, the lap joint shall be welded, and the weld length shall not be less than 5d.
(5) The stirrups at the upper and lower ends of the column should be encrypted, and the length and spacing of stirrups in the encrypted area should meet the requirements of design drawings and construction specifications and be less than or equal to 100mm and not more than 5d. If the design requires stirrups to be provided with tie bars, the tie bars should be hooked on the stirrups, as shown in Figure 4.
(6) The protective layer thickness of column rebar should meet the specification requirements. The protective layer thickness of main rebar is 25mm, and a cushion block is tied on the protective layer of column vertical rebar, and the spacing is generally 1000mm (or plastic card is used on the lateral vertical rebar) to ensure the accuracy of the protective layer thickness of main rebar. At the same time, the steel bar spacing frame can be used to ensure the correctness of the steel bar position. When the column section size changes, the column should be bent in the plate, and the bending size should meet the design requirements.
(7) Braces or embedded parts of the wall shall be reserved according to the materials used in the wall and related drawings.
(8) When the column rebar reaches the top of the structure, special attention should be paid to the anchorage length of the column rebar outside the side column as 1.7 1ae. See 03G329- 1 (civil frame, frame-shear wall, frame partially supported shear wall) for details. At the same time, attention should be paid to the anchoring direction of column reinforcement when connecting reinforcement, so as to ensure that column reinforcement is correctly anchored to beams and plates.
(2) Shear wall steel binding
1, process flow:
Erect 2-4 vertical bars-draw the spacing between horizontal bars-tie the horizontal bars-tie other horizontal bars and vertical bars.
2. Erect 2-4 vertical bars: tie the vertical bars with overlapping bars protruding from the lower layer, draw horizontal bar grading marks on the vertical bars, tie two horizontal bars at the lower part and chest level for positioning, draw vertical bar grading marks on the horizontal bars, then tie the remaining vertical bars, and finally tie the remaining horizontal bars. Transverse reinforcement should meet the design requirements on the inside or outside of vertical reinforcement.
3. Three horizontal steel bars shall be bound at the lap of vertical steel bars and extended lap steel bars, and the lap length and position shall meet the design requirements.
When there is no requirement, the construction shall be carried out according to Table 2. Table 2
Project reinforcement type, strength grade of compacted concrete.
C20C25C30
1 Grade I reinforcement 35d (30d) 30d (25d) 25d (20d)
Grade 2II reinforcement (crescent) 45d 40d 35d
3 Grade 3III rebar (crescent) 55d 50d 45d
Note: The figures in brackets refer to the lap length of the welded mesh binding joint.
4, shear wall reinforcement should be binding point by point, should be tied between double rows of reinforcement brace or support rod, the vertical and horizontal spacing is not more than 600mm, steel sheath binding block or plastic card.
5. At the joint of shear wall and frame column, the horizontal bar of shear wall should be anchored on the frame column, and its anchoring length should meet the design requirements. For example, when pouring column concrete first and then binding shear wall reinforcement, it is necessary to reserve connecting reinforcement in the column or embed iron pieces in the column as the connection when dismantling column and binding wall reinforcement. Its reserved length should comply with the provisions of the design or specification.
6. The anchorage length of horizontal reinforcement of shear wall at both ends, corners, cross joints, coupling beams and surrounding reinforcement of the hole should meet the design and seismic requirements.
7. After closing the mold, the protruding vertical reinforcement shall be trimmed, and the protruding vertical reinforcement shall be fixed with angle steel or ladder reinforcement at the top of the template. When pouring concrete, there should be someone to take care of it. After pouring, it should be adjusted again to ensure the accurate position of steel bars.
(3) Beam steel binding
1, process flow:
Draw the stirrup spacing of primary and secondary beams-put the stirrup beams of primary and secondary beams in place-pass through the longitudinal bars at the bottom of the main beam and bend the bars-pass through the longitudinal bars at the bottom of the secondary beam and fix them with stirrups-pass through the longitudinal bars at the top of the main beam and erect the vertical bars-bind according to the stirrup spacing-pass through the longitudinal bars at the top of the secondary beam-bind according to the stirrup spacing.
2. Draw the stirrup spacing on the beam side formwork and place the stirrup.
3. First, pass through the longitudinal stress reinforcement and bending reinforcement at the lower part of the main girder, and separate the stirrups one by one according to the drawn spacing; Wear the longitudinal stressed steel bars and bent steel bars at the lower part of the secondary beam, and set stirrups; Put the scissors of primary and secondary beams; Tie up the installation stud and stirrup at regular intervals; Adjust the stirrup spacing to the design requirements, tie the stud, then tie the main reinforcement, and coordinate the primary and secondary. The upper longitudinal reinforcement of the secondary beam should be placed on the upper longitudinal reinforcement of the main beam. In order to ensure the protective layer thickness of secondary beam reinforcement and the position of plate reinforcement, the upper reinforcement of main beam can reduce the diameter of the upper main reinforcement of secondary beam.
The upper longitudinal reinforcement of the frame beam should run through the middle node, and the anchorage length of the lower longitudinal reinforcement of the beam should meet the design requirements. The anchorage length of longitudinal reinforcement at the end node of frame beam should also meet the design requirements, generally greater than 45d. Tie the stirrups of the upper longitudinal reinforcement of the beam by the method of set buckle, as shown in Figure 5.
5. The stirrup hooks at the lap joint in the beam should be staggered. Hook of stirrup shall be 1350, and the length of straight part shall be 1Od. If the closed hoop is made, the length of one-sided weld is 5d.
6. The first stirrup at the beam end should be set 50mm away from the edge of the column node. The stirrups at the junction of beams and columns should be encrypted, and their spacing and encryption zone length should meet the design requirements. At the beam-column joint, because the beam reinforcement penetrates into the column reinforcement, the protective layer of the beam reinforcement is increased, so gradient stirrups should be adopted, and the gradient length is generally 600mm to ensure that the stirrup and beam reinforcement are firmly bound in place.
7. Cushion blocks (or plastic cards) should be placed under the stressed steel bars of the main beam and the secondary beam to ensure the thickness of the protective layer. When the stressed steel bars are in double rows, short steel bars can be placed between the two layers of steel bars, and the row spacing of steel bars should meet the requirements of design specifications.
8. Lapping of beam reinforcement: When the diameter of the stressed reinforcement of the beam is equal to or greater than 22mm, welded joints or mechanical connection joints should be adopted; When it is less than 22mm, the binding joint should be adopted, and the lap length should comply with the regulations. The distance between the end of the lap length and the bend of the steel bar should not be less than 10 times the diameter of the steel bar. The joint should not be located at the maximum bending moment of the member. In the tension zone, the ends of the binding joints of Grade I steel bars should be hooked (Grade II steel bars are not required to be hooked), and the lap joints should be fastened at the center and both ends. The positions of the joints should be staggered. When binding lap joints are used, the cross-sectional area of steel bars with joints accounts for the percentage of the total cross-sectional area of steel bars in any section with specified lap length, and the tensile area is not more than 50%.
(4) plate steel binding
1, process
Clean the template-draw lines on the template-tie the reinforced bar under the plate-tie the negative bending moment reinforced bar.
2. Clean up the sundries on the template, use Mo Dou to play the main reinforcement on the template, and divide the reinforcement spacing line.
3, according to the planned spacing, put the main reinforcement first, then put the distribution reinforcement. Embedded parts, electrical conduits and reserved holes shall be installed in time.
4. When there is a plate beam in the cast-in-place slab, the plate beam reinforcement shall be bound first, and then the plate reinforcement shall be placed. When binding plate reinforcement, straight buckle (Figure 6) or splayed buckle is generally adopted. Except for the intersection of two peripheral tendons, other points can be bound alternately (all intersections of two-way slabs must be bound).
Figure 6
5, such as plate for double reinforcement, reinforcement horse stool must be added between the two layers of reinforcement, to ensure the position of the upper reinforcement. Each intersection of negative moment reinforcement shall be bound.
6, reinforced mortar pad, spacing1.5mm. The thickness of the pad is equal to the thickness of the protective layer, which should meet the design requirements. If there is no requirement in the design, the thickness of the protective layer of the plate should be 15 mm, and a horse stool should be installed at the lower part of the cover iron in the same position as the pad iron.
(5) Stair steel binding
1, process
Draw position line-tie main reinforcement-tie local reinforcement-tie step reinforcement.
2. Draw the position lines of main reinforcement and distribution reinforcement on the stair board.
3. According to the direction of main reinforcement and distribution reinforcement in the design drawings, tie the main reinforcement first and then the distribution reinforcement, and tie each intersection. If there is a stair beam, tie the beam first, and then tie the slab reinforcement. Plate reinforcement should be anchored in the beam.
4. After the bottom plate reinforcement assembling is completed, after the step template is supported, the step reinforcement shall be assembled again. The number and location of main reinforcement joints shall comply with the provisions of construction specifications.
(6) finished product protection
1. After the bent steel bar of the floor is tied with the negative moment steel bar, it is not allowed to walk on it. When pouring concrete, send steel workers to repair it to ensure the correctness of the negative bending moment steel bar position.
2. When binding reinforcement, it is forbidden to touch the embedded parts and the template of the hole.
3. Don't pollute the steel bars when the steel formwork is coated with isolation agent.
4, the installation of wire tube, heating pipe or other facilities, shall not be arbitrarily cut off and move the steel bar.
(7) Quality problems that should be paid attention to.
1, before pouring concrete, check whether the rebar position is correct, and prevent rebar from colliding when vibrating concrete, that is, trim rebar position to prevent column rebar and wall rebar from shifting.
2. The skeleton size of beam reinforcement is smaller than the design size: stirrups should be calculated according to the endothelial size.
3. Stirrups in the core area of beams and columns should be encrypted, and be familiar with drawings and construction as required.
4, stirrup end should be bent into 135 degrees, the length of the straight part is 10d.
5, beam main reinforcement into the bearing length should comply with the design requirements, bending steel position accurately.
6, plate bending reinforcement and negative bending moment reinforcement position should be accurate, should not be trampled down during construction.
7, tie plate cover iron reinforcement should pull line, tie straight at any time, to prevent the plate reinforcement is not straight, the position is not allowed, the look and feel is not good.
8. When binding vertical reinforced bars, they should be hung upright, and three buckles should be tied at the lap joint, not in the same direction. When the storey height is more than 4m, erection and binding shall be carried out, and measures shall be taken to fix the reinforcement to prevent the column and wall reinforcement skeleton from being vertical.
9, pay attention to the ingredients when processing steel, end with butt welding head, to avoid the lap range, to prevent the binding joint and butt welding head confusion.