Reinforcement Bar Specifications
Rebar Engineering
5.1 Material Requirements
5.1.1 Steel bars should have factory quality certificates and inspection reports , and samples are taken in batches according to regulations for mechanical performance inspection, and they can only be used after passing the test.
5.1.2 The surface of the steel bars or each bundle (coil) of steel bars should be marked; there should be no cracks, scars, creases or corrosion on the surface of the steel bars.
5.2 Steel bar processing
5.2.1 Steel bar processing and production are carried out on site, and steel bar bending machines, steel bar cutting machines and winches are equipped for steel bar processing.
5.2.2 Technical personnel are responsible for preparing the steel bar batching list, and the operators process the steel bars strictly according to the steel bar batching list to ensure correct dimensions.
5.2.3 For steel bars in special and complex parts, a sample should be enlarged before processing, and then processed and produced after verification, so that the dimensions are in accordance with the drawings and the operation is in accordance with the specifications.
5.2.4 Strictly follow the operating procedures and quality standards. The formed steel bars must be listed, classified and stacked, stored in the steel bar shed, and protected against rust.
5.2.5 Welders must have on-the-job operation certificates. Before steel bar welding construction, steel bar test welding should be performed first. Construction welding can only be carried out after passing the test. Sampling tests of steel bar welded joints shall be carried out in accordance with the requirements of the specifications.
5.2.6 The stirrup hooks should meet 135°, and the length of the straight part should not be less than 10 times the stirrup diameter.
5.2.7 First-level round steel bars should be straightened before processing, and the cold drawing rate should be controlled within 4%.
5.3 Installation of steel bars
5.3.1 Installation of foundation steel bars
5.3.1.1 The intersection points of the two steel bars around the base steel bars should be firmly tied at each point, and the intersection point in the middle Every other steel mesh with a plum blossom shape and two-way force-bearing main bars should be firmly tied at the intersection points of all steel bars. The fasteners at adjacent binding points should be in a figure-eight shape to prevent the mesh from skewing and deforming.
5.3.1.2 The lower ends of the insertion bars used to connect the cast-in-place columns, walls and foundations are tied with the foundation steel bars with 90° hooks. The insertion positions should be firmly fixed with steel bars in a tic-shaped shape to avoid causing damage to the column reinforcements. Displacement.
5.3.1.3 When the foundation is equipped with a double-layer steel mesh, steel support feet (thread φ14@1000, two-way) should be set under the upper layer of steel mesh to ensure the correct spacing and position of the upper and lower steel bars.
5.3.1.4 The cap, cap connecting beams and waterproof bottom plate steel bars are all connected by flash butt welding, and the joint percentage is controlled within 50%.
5.3.2 Installation of steel bars for shear walls and columns (edge ??components of shear walls)
5.3.2.1 The plane position and verticality are corrected before binding.
5.3.2.2 The positions of the steel bar joints of the shear wall and columns (edge ??members of the shear wall) are staggered according to the design regulations. The steel bars of the shear wall are connected by binding and overlapping. The columns (edge ??members of the shear wall) are longitudinally stressed. The joints of the force steel bars are connected by electroslag pressure welding. According to the requirements of the specification and atlas, the percentage of the joints of the two steel bars is controlled to be no more than 50%.
5.3.2.3 The stirrup density area shall be arranged according to regulations, and the density stirrups in beam and column nodes shall be laid out in order in advance. Where the stirrup hooks overlap, they should be staggered on the longitudinal steel bars at the four corners; the corners of the stirrups and the intersections of the longitudinal steel bars should be firmly tied, and the buckles should form a figure-eight shape with each other when tying the stirrups. The stirrup ends of columns (edge ??components of shear walls) should be 135°, and the straight length should not be less than 10d. 5.3.2.4 Column steel bar control protective layer uses plastic positioning cards to be stuck on the outer skin of the column's main bars, with a spacing of 1000mm to ensure the thickness of the main bar protective layer.
5.3.3 Installation of beam steel bars
5.3.3.1 Process: Pass the main bars through the stirrups, separate them one by one according to the designated spacing → fix the main bars → pass through the secondary beam steel bars and set them up stirrups → place the main beam to set up the vertical bars and the secondary beams to set up the vertical bars → tie the main bars at the bottom of the beam to the stirrups at a certain distance → tie the vertical bars → tie the main bars again. The primary and secondary beams are carried out simultaneously.
5.3.3.2 Where the main beam and the upper longitudinal steel bar of the secondary beam meet, the primary and secondary beam steel bars and the secondary beam steel bars are placed on the main beam steel bars.
5.3.3.3 When the longitudinal load-bearing steel bars are arranged in double layers, short steel bars with a diameter of 25mm should be placed between the two rows of steel bars. The spacing between the short bars should be ≤1000mm.
5.3.3.4 The upper steel bars of the side beams at the end of the cantilever beam are distributed on the upper part of the cantilever beam bars.
5.3.3.5 The joints of beam stirrups (overlapping hooks) should be staggered on the two supporting steel bars.
5.3.3.6 The four-corner main bars should be tied with horse-riding buckles to make the main bars match the arc part of the beam hoop.
5.3.3.7 The location of the first stirrup is 50mm from the edge of the wall or column.
5.3.3.8 Beam steel bar joints shall be connected by flash butt welding, and the joint percentage shall be controlled within a range of no more than 50%.
5.3.3.9 Location of steel bar joints: The upper rubber bar joints remain within 1/3 of the mid-span, and the lower skin steel bar joints remain within the supports and meet the anchorage length requirements.
5.3.4 Installation of plate steel bars
5.3.4.1 Before binding, the formwork should be trimmed, the garbage and debris on the formwork should be cleaned, and the main bars should be divided with chalk on the formwork according to the designed spacing. , the installation position of the distribution ribs.
5.3.4.2 Arrange the stress-bearing main reinforcements first and then the distribution reinforcements according to the marked spacing. Embedded parts, wire tubes, reserved holes, etc. should be installed and fixed at the same time.
5.3.4.3 No joints are left for the steel bars at the bottom of the plate, and the ends of the steel bars are directly embedded in the supports according to the anchorage length required by the design.
5.3.4.4 For the bottom steel bars of the two-way slab, the short span steel bars are in the lower row and the long span steel bars are in the upper row.
5.3.4.5 When the hole size on the board is ≤300mm, the steel bars are generally bypassed from the edge of the hole. When the size is >300mm, reinforcement bars are installed according to the design requirements.
5.3.4.6 In order to ensure the effective height of the upper layer of bars between the double-layer mesh bars, several-shaped support bars are set up. Generally, the vertical and horizontal spacing is φ10@600mm, and the length of the support legs is not less than 200mm.
5.3.4.7 The intersection points of the two rows of steel bars around the plate bars should be fastened firmly at each point, and the intersection points in the middle can be fastened at intervals and staggeredly; but the correct position of the steel bars must be ensured, and the steel mesh of the main bars bearing two-way stress should be All the intersection points of the steel bars should be firmly tied, and the fasteners at adjacent binding points should be in a figure-eight shape to prevent the mesh from skewing and deforming.
5.3.4.8 At the intersection of the plate, secondary beam and main beam, the plate steel bars are on top, the secondary beam steel bars are in the middle, and the main beam steel bars are on the bottom.
5.3.4.9 When tying the steel bars of beams and slabs, water and electricity pipelines should prevent the steel bars from lifting or pressing down.
5.3.5 Binding of stair steel bars
5.3.5.1 On the supported template of the stair, pop up the position lines of the main bars and distribution bars. According to the arrangement of the main reinforcement and distribution reinforcement in the design drawing, tie the main reinforcement first, then the distribution reinforcement, and each intersection should be tied. If there is a stair beam, tie the beam first, then tie the plate steel bars, and the plate steel bars should be anchored into the beam.
5.3.4 Installation of plate steel bars
5.3.4.1 Before binding, the formwork should be trimmed, the garbage and debris on the formwork should be cleaned, and the main bars should be divided with chalk on the formwork according to the designed spacing. , the installation position of the distribution ribs.
5.3.4.2 Arrange the stress-bearing main reinforcements first and then the distribution reinforcements according to the marked spacing. Embedded parts, wire tubes, reserved holes, etc. should be installed and fixed at the same time.
5.3.4.3 No joints are left for the steel bars at the bottom of the plate, and the ends of the steel bars are directly embedded in the supports according to the anchorage length required by the design.
5.3.4.4 For the bottom steel bars of the two-way slab, the short span steel bars are in the lower row and the long span steel bars are in the upper row.
5.3.4.5 When the hole size on the board is ≤300mm, the steel bars are generally bypassed from the edge of the hole. When the size is >300mm, reinforcement bars are provided according to the design requirements.
5.3.4.6 In order to ensure the effective height of the upper layer of bars between the double-layer mesh bars, several-shaped support bars are set up. Generally, the vertical and horizontal spacing is φ10@600mm, and the length of the support legs is not less than 200mm.
5.3.4.7 The intersection points of the two rows of steel bars around the plate bars should be firmly tied at each point, and the intersection points in the middle part can be staggered and fastened at intervals; but the correct position of the steel bars must be ensured, and the steel mesh of the main bars bearing two-way stress should be All the intersection points of the steel bars should be firmly tied, and the fasteners at adjacent binding points should be in a figure-eight shape to prevent the mesh from skewing and deforming.
5.3.4.8 At the intersection of the plate, secondary beam and main beam, the plate steel bars are on top, the secondary beam steel bars are in the middle, and the main beam steel bars are on the bottom.
5.3.4.9 When tying the steel bars of beams and slabs, water and electricity pipelines should prevent the steel bars from lifting or pressing down.
5.3.5 Stair steel bar binding
5.3.5.1 On the template of the stair support, pop up the position lines of the main bars and distribution bars. According to the arrangement of the main reinforcement and distribution reinforcement in the design drawing, tie the main reinforcement first, then the distribution reinforcement, and each intersection point should be tied. If there is a stair beam, tie the beam first, then tie the plate steel bars, and the plate steel bars should be anchored into the beam.