1. Operation process
1. Process flow: Draw the steel bar location line → Transport the steel bars to the use site → Tie the bottom plate and beam steel bars → Tie the wall steel bars.
2. Draw the steel bar position line: According to the steel bar spacing indicated on the drawing, calculate the actual number of steel bars required for the base plate. Generally, the steel bar close to the edge of the base plate formwork should be 5cm away from the edge of the formwork. On the base plate The rebar position line pops up.
3. Tie the foundation floor and foundation beam steel bars
(1) According to the pop-up steel bar position line, lay the lower steel bars of the floor first. According to the stress situation of the bottom plate, it is decided which direction of the lower steel bars is underneath. Generally, the short steel bars are laid first, and then the long steel bars are laid.
(2) When tying steel bars, the intersection points of the two rows near the periphery should be tied at each point. The intersection points in the middle part can be tied alternately and staggered. For steel bars that bear force in both directions, all intersection points of the steel bars must be tied. If one side buckle is used, the direction should be changed in a staggered manner, or a figure-eight buckle can be used, but the steel bar must not be displaced.
(3) Use mortar pads to place the concrete protective layer of the base plate. The thickness of the pads is equal to the thickness of the protective layer and placed in a plum blossom pattern every 1m or so. If the foundation floor is thicker or the foundation beam and floor use a large amount of steel, the placement distance can be reduced, or even the mortar pads can be replaced with iron blocks.
(4) The basic base plate is made of double-layer steel bars. After tying the lower steel bars, place a steel horse stool or steel bar bracket (the distance between them is about 1m), and place two horizontal bars on the horse stool. The orientation of the steel bars, the upper and lower order of the steel bars and the fastening method are the same as the lower steel bars of the base plate.
(5) When the bottom plate steel bars have tied joints, the overlap length and overlap position of the steel bars should comply with the requirements of the construction specifications. The overlap of the steel bars should be tied firmly at the center and both ends with iron wires. The bottom plate steel bars are connected with straight threads. In addition to taking sample samples according to regulations, the joint locations should also comply with the construction specifications.
(6) Due to the special stress of the foundation floor and foundation beam, the locations of broken steel bars on the upper and lower floors should meet the design requirements.
(7) According to the elastic wall and column position lines, tie the insertion bars of the walls and columns into the foundation firmly. The depth of insertion into the foundation must meet the design requirements. The throw-out length should not be too long. The upper end of the bars should not be too long. Measures should be taken to ensure that the ribs are vertical and not tilted, tipped or displaced.
4. Wall reinforcement binding:
(1) Pop up the wall and door and window opening position lines on the base concrete, and correct the embedded reinforcement again. If there is any displacement, adjust according to regulations Handle it carefully. The wall formwork should use "jump formwork" to facilitate the construction of steel bars.
(2) First tie 2 to 4 vertical bars and draw the markings for the horizontal bars. Then tie two horizontal bars at the lower part and at chest level for positioning, and draw the markings for the vertical bars. Generally, the horizontal bars are on the outside and the vertical bars are on the inside, so tie the vertical bars first and then the horizontal bars. The spacing and location of horizontal and vertical bars should meet the design requirements.
(3) The wall reinforcements are bidirectional stress-bearing steel bars. All intersection points of the steel bars should be tied point by point. The length and location of the tower connections must comply with the requirements of the design drawings and construction specifications.
(4) Spacing supports or tie bars should be tied between double rows of steel bars to fix the spacing between the steel bars. Supports or tie bars are set according to the drawing requirements to ensure the distance between double rows of steel bars.
(5) Mortar pads or plastic pads with iron wires should be tied to the outside of the wall reinforcements to ensure the thickness of the protective layer.
(6) In order to ensure the correct elevation position of the door and window openings, draw elevation lines on the vertical ribs of the openings. The door and window openings must be tied with lintel steel bars according to the design requirements, and the length of anchors into the wall must meet the design requirements.
(7) The seismic structural steel bars and anchorage lengths of each connection point should be tied according to the design requirements. For example, the longitudinal stress-bearing steel bars of the first-floor columns extend into the depth of the basement wall; the anchorage length of the stress-bearing steel bars at the end of the wall and the junction of the inner and outer walls, etc., should be paid attention to when tying.
(8) Cooperate with other types of work to install embedded pipe fittings, reserved holes, etc. Their locations and elevations should meet the design requirements.
2. Quality Standards
1. Guarantee items:
(1) Type and quality of steel bars, grades and properties of welding rods and fluxes, and steel plates used , must comply with design requirements and relevant standards. Before welding imported steel bars, chemical composition inspection and welding tests must be carried out. Welding can only be done after meeting relevant regulations.
(2) The surface of the steel bars must be clean. Steel bars with granular or flaky old rust or pitted steel bars after rust removal are strictly prohibited from being used according to the original specifications.
(3) The specification, shape, size, quantity, spacing, anchoring length, and joint settings of the steel bars must comply with the design requirements and construction specifications.
(4) Straight threaded joints must meet mechanical properties and meet design requirements.
2. Basic items:
(1) The number of missing and loose buckles of tied steel bars shall not exceed 10% of the number of tied buckles and shall not be concentrated.
(2) The direction of the hook should be correct, the binding joints should comply with the construction specifications, and the overlap length should not be less than the specified value.
(3) The number of stirrups made of Grade I steel bars should comply with the design requirements, and the hook angle and straight length should comply with the construction specifications.
3. Finished product protection
1. Formed steel bars should be stacked in designated locations and neatly placed with wooden pads to prevent deformation, corrosion, and oil stains on the steel bars.
2. When tying wall bars, a temporary frame should be set up, and no stepping on the steel bars is allowed.
3. Properly protect the exposed waterproof layer around the foundation to avoid being damaged by steel bars.
4. When tying the steel bars on the bottom and lower floors, the supporting horse stools must be tied firmly to prevent deformation during operation. 5.5 It is strictly prohibited to cut the steel bars at will.
IV. Quality issues that should be paid attention to
1. Displacement of pre-embedded steel bars in walls and columns: The insertion bars of the main bars of walls and columns and the lower and upper bars on the floor must be fixed and tied firmly to ensure The location is accurate. If necessary, additional steel bars can be welded firmly by electric welding. Special personnel should be inspected and trimmed before concrete is poured.
2. Exposed reinforcements: Add cement mortar pads (or plastic cards) with iron wires every 1m or so to the steel bars of walls and columns.
3. Insufficient overlap length: Each joint should be measured when binding to check whether the overlap length meets the design and specification requirements.
4. Wrong position of steel bar joints: When there are many steel bar joints in beams, columns, and walls, when processing the sample batching, a construction sample drawing should be drawn in advance according to the drawings, indicating the matching sequence of each number of steel bars, and Avoid the maximum bending moment of stressed steel bars.
5. The lashing joints and butt welding joints are not staggered: When the butt welded steel bars are tied on site, the butt welding joints must be staggered in the overlapping position. Therefore, when processing and blanking, no butt welding joints are allowed within the overlap length range from the end of the steel bar.