Cast-frame structure reinforcement technology

Cast-frame reinforcement

1 scope

This technology is applicable to multiple industrial and civil building in-situ frame, frame-shear wall structure reinforcement project.

2 construction preparation

2.1 materials and equipment:

2.1.1 steel: mechanical properties of factory certification, in accordance with the regulations for the second interview. Special circumstances such as when the brittle fracture occurred during processing, the need for chemical composition test. Bars should be no old rust and oil.

2.1.2 bars: must comply with the specifications, size, shape and quantity of the charge sheet and certificate of processing factory.

2.1.3 wire: use of 20~22 wire (wire) or galvanized iron wire (wire). Wire cutting length to meet the requirements of.

2.1.4 pads: made with cement mortar, 50mm square, thickness of protective layer break block embedded wire, 20~22. Or use plastic cards, pull bars, support bars.

2.1.5 major equipment: steel hooks, crowbar, wrench, and tie racks, trolleys, wire brushes, chalks, rulers, etc.

2.2 operating conditions:

2.2.1 steel comes into play should check whether the factory certificate and retest report and specifying the position according to the construction plan, according to specifications, using position, padded wooden stacking number respectively.

2.2.2 before reinforcement, you should check for corrosion, rust and then transported to the binding site.

2.2.3 familiarity with drawing paper, according to the design requirements of checks processed steel specifications, shape, quantity is correct.

2.2.4 copying flat-line work, perfect level elevation line, column and wall outside dimension line.

2.2.5 under skin elasticity and good lines, check the lower reserved the location, number and length of lap steel, if it does not meet requirements, should be processed. Before you binding finishing straightens the lower out of the lap bar, clean, cement mortar, dirt and corrosion.

2.2.6 under height check the concrete surface elevation at the lower out of the lap bar (roof, walls) it meets the requirements of drawing, such as a loose false, to remove and clean.

2.2.7 installation finished and go through pre-clearance, clean up the template clutter.

2.2.8 set up scaffolding as required.

2.2.9 in accordance with design drawings, specifications and technical standards, and technology to give the low-down to the team.

3 operational processes

3.1 tied pillar reinforcement:

3.1.1 technological process:

Sets of column Stirrup → lap → picture vertical stress reinforcement binding → Stirrup spacing lines tied to Stirrups

3.1.2 sets of column reinforcement: spacing according to the drawings, calculate each column number of Stirrups, Stirrup set on the lower out of the lap bar and vertical pillar reinforcement, lap length, tie buckles not less than 3, tied to buckle to the center column. If column main bars with plain round bar overlap, into a 45 ° corner hooks and template, intermediate steel hook and a template into a 90 ° angle.

Lap banding vertical stress reinforcement: column reinforcement after set up, joint banding lap length comply with design requirements, such as when there is no requirement, should according to table 4-10.

Tensile reinforcement joints of lap length table 4-10

Concrete strength

C20 C25 C30

1 grade ⅰ reinforcement 35d 30D 25D

2 grade steel (Crescent-shaped) 45d 40D 35d

3 grade ⅲ steel bar (Crescent-shaped) 55d 50d 45d

Note: 1. When level ⅰ and ⅱ steel bar d>25mm,, the lap length should be increased according to the values in the table 5d.

2. when the rebar diameter ≤ 25mm, the tensile reinforcement, lap length reduced by values in the table 5d.

3. lap length is not less than 300mm under any circumstances. Binding joints should be staggered. From any binding Joint Center to the lap length of 1.3 times the sector-wide, binding joints reinforcement of cross-sectional area a percentage by the total cross-sectional area of steel bars: tension must not exceed 25%; compression zone must not exceed 50%. When welding is used from any Center to length of welded joints for steel bar diameter of 35 times within the section and not less than 500mm, joints reinforced with steel area percentage of total area: tension should not exceed 50%; compression zone is not restricted.

3.1.4 draw Stirrup spacing lines: made good posts on the vertical reinforcement and stirrup spacing with the chalk line according to the drawings.

3.1.5 column Stirrup straps

3.1.5.1 by drawing good hoops position line, will have good hoop to move lashing from the top down, wrapped buckle fastening should be used, as shown in Figure 4-19.

3.1.5.2 hoop perpendicular to the main bar, hoop corner and main bar intersection to tie, reinforcement and stirrup corner part of staggered intersection into a plum tie.

3.1.5.3 hoop hook overlapping vertical bars along the pillar staggered and binding firm, as shown in Figure 4-20.

3.1.5.4 the seismic requirements of column Stirrup head should bend 135 °, length of straight section not less than 10d (d is Hoop diameter), as shown in Figure 4-21. Such as Stirrups with 90 ° overlap lap welding, weld length single weld is not less than 5d.

Figure 4-19

1, 2, 3, 4 – binding order

图4-20 图4-21

3.1.5.5 pillars at both ends Stirrups should be encrypted, encryption length and encrypting the Stirrup spacing should comply with the design requirements of the drawing. As design requirements when the reinforcement is Hoop, lacing hook Stirrups, as shown in Figure 4-22.

Figure 4-22

3.1.5.6 column thickness, the specification requirements, main bar skin 25mm, blocks should be tied in cylindrical vertical bars on the outer skin, space 1000mm, (or card a plastic card on the outer vertical bars) to ensure the main rib thickness accurate. When the column size changes, the column should be bent in the Board, bending dimensions in line with the design requirements.

3.2 tie shear walls:

3.2.1 the process flow:

Li → 2~4 → vertical reinforcement to draw level with disabilities margin tied tied the remaining cross bars position cross bars → → tied the remaining branches in bar

3.2.2 State 2~4 vertical bars: the vertical bars and lower out of the lap bar tie, draw horizontal logo on the vertical bar in the lower chest and tied to two cross bars position and cross-bar painted on the vertical bar symbol, then tie the remaining vertical bars, and finally tied the remaining cross bars. Cross bar in vertical bars inside or outside, the design requirements.

3.2.3 vertical bars and tie out of the lap bar lap need 3 horizontal bars, lap length and the location should comply with the design requirements and design requirements, according to table 4-11 construction.

Table 4-11

Concrete strength

C20 C25 C30

Grade ⅰ reinforcement 1 35d (30D) 30D (25D) 25D (20D)

2 grade steel (Crescent lines) 45d 40D 35d

3 grade ⅲ steel bar (Crescent lines) 55d 50d 45d

Note: the figures in bracket denote binding welded joint of lap length.

3.2.4 wall reinforcement should be lashing point by point, between two rows of steel tie bar or support bar, the vertical and horizontal spacing shall not exceed 600mm, steel outer skin binding blocks or plastic card.

3.2.5 the scissors at the junction of walls and columns, shear walls within a column of horizontal bars must be anchored to the frame, the anchorage length to meet the design requirements. Pouring concrete before they are tied to a pair of scissors at the stud, or column you want to reserve the connection reinforcement column embedded in iron, column removal tie as connected with Stud. Reserve length should comply with the design or specification of the requirements.

3.2.6 shear wall with horizontal ribs on both sides, rotation, 10 bytes, beams and other parts of anchorage length of reinforcement bars and around the hole, shall comply with the design seismic requirements.

3.2.7 die out after trimming the vertical reinforcement should be should be tied to a cross bar at the lap position, special care compensate for pouring concrete, again after adjusting the position of the reinforcement to ensure accurate pouring.

3.3 beam reinforcement:

3.3.1 processes:

In-mold banding: primary and secondary beam Stirrup spacing → painting Master Liang Ciliang → wore Stirrup bottom longitudinal reinforcement and bend reinforcement of main beam →

Put bottom longitudinal reinforcement and the secondary beams with longitudinal frame of main beam upper Stirrup fixation → wear Stud →

Stirrup spacing straps worn upper beam longitudinal reinforcement → → Stirrup spacing straps

Mode binding (catchy lashing after forming the beam template first and then into the mould):

→ Painting hoop spacing in the primary and secondary beam template catchy laying Rails put Stirrups on Rails → →

Wearing lower longitudinal reinforcement of main beam → secondary beams through the lower main girder of steel → wearing the upper steel Stirrup spacing straps → →

Worn upper beam longitudinal bar → Stirrup spacing lashing →→→

3.3.2 in the beam side draw out of the Stirrup spacing on the template, placed Stirrups.

3.3.3 first wear main beam of lower longitudinal by force steel and the bent up steel, will hoop reinforced by has painting good of spacing individually separate; wear times beam of lower longitudinal by force steel and the bent up steel, and sets good hoop reinforced; put primary and secondary beam of frame State reinforced; across must spacing will frame State reinforced and hoop reinforced lashing firm; adjustment hoop reinforced spacing makes asked from meet design requirements, kidnapping state reinforced, again tied main reinforced, primary and secondary beam while tie for.

3.3.4 upper frame beam reinforcement through intermediate nodes, anchoring the middle of the lower part of the beam into longitudinal reinforcement node length and extending across the center line of length should comply with the design requirements. Frame beam longitudinal reinforcing bar anchorage length in the end node must meet the design requirements.

3.3.5 tie beam longitudinal reinforcement of the stirrup, to use the deduction method binding, as shown in Figure 4-23.

Figure 4-23

1, 2 and 3-binding order

3.3.6 hoop hook at the composite, beam cross banding, Stirrup bending hooks for 135 °, straight part length of 10d, such as closed when the hoop, one side seam length of 5d.

3.3.7 beam the first should be set at a distance of column joint Stirrup edge 50mm. Junction of beam and column Stirrup should be encrypted, head of spacing as encrypted to comply with design requirements.

3.3.8 in both primary and secondary beam force reinforced cushion pad (or plastic card) to ensure that the thickness of the protective layer. When loading reinforcement for double-row, available short reinforcement pad in between two layers of steel, steel row spacing should comply with the design requirements.

3.3.9 beam bar overlap: the reinforcement of the beam diameter is equal to or greater than 22mm, the welded joints should be used, is less than 22mm, can be used binding joints, lap length comply with the norms. Lap length ends with steel bars bending distance shall not be less than 10 times times the bar diameter. Joints should not be located in the maximum bending moment, tension in the region should be done at the end of grade ⅰ reinforcement joints hook (class ⅱ steel bar can not hook), the overlap in the Center and fastened at both ends. Joints should be staggered when using binding when the lap joint, lap length under any of the sections within the joints of the steel section

Area percentage by the total cross-sectional area of steel bars, the tension is less than 50%.

3.4 plate reinforcement:

3.4.1 process:

Cleanup tie → template → a template to draw lines Board short tie → stress tendons under negative bending steel bars

3.4.2 clean up debris above the template, template marked with chalk reinforcement, distribution bar spacing.

3.4.3 press the marked space, placed after main bearing reinforcement, distribution bars. Embedded parts, wires and pipes, reserved hole in time to meet the installation.

3.4.4 when you have plates with beam slab should be tied to sheet and strip steel, again placing reinforcement.

3.4.5 binding plate gluten generally Shun buckle (Figure 4-24) or Bazi buckle, apart from the perimeter outside the intersection point of the two tendons shall be fully binding, lashing the remaining points can be staggered (two-way slab intersection point to all binding). Plate for double-layer bars shall be added between two layers of reinforced steel bar stools, to ensure that the position of the top layer. Negative moment reinforcement lashing at each intersection.

Figure 4-24

1, 2 and 3-binding order

3.4.6 in the steel pad under good mortar, 1.5M. The thickness is equal to the thickness of the pad, shall meet the design requirements, such as design requirements, the thickness of the plate should be 15mm, lap length and lap steel position requirements and beam the same described above.

3.5 reinforcement of the stairs:

3.5.1 process:

Line tie tied tie → reinforced → distribution → reinforced step bars

3.5.2 in the main bar on the bottom of the stairs and the location of the distribution bar line.

3.5.3 in accordance with design drawings in the main bar, direction of distribution bars, first lashing bars lashing after contour bars, each node should be binding. If you have stair beams, tie plates with tie beam reinforcement. Tendons anchored to welded connction.

3.5.4 bottom bars tied up tied hanging template to mark time after the binding step bars. Number and location of main bar joints must conform to the provisions of the code.

4 quality criteria

4.1 project:

4.1.1 steel variety and quality must comply with the design requirements and the provisions of the relevant standard.

4.1.2 steel surfaces must be clean. With a granular or flaky old rust, rust remains after pitting of steel, according to the original specifications is strictly prohibited. Steel surfaces should be kept clean.

4.l.3 bar sizes, shapes, sizes, quantity, location of anchorage length, connector, you must meet the requirements of specification for design and construction.

4.1.4 results of reinforcement on mechanical properties of welded joints, welded steel and acceptance of special requirements must be met.

4.2 Basic project:

4.2.1 short buckle, tie loose quantity does not exceed 10% of buckle, and should not be set.

4.2.2 hook should be correct, lashing fittings shall conform to the provisions of the code, lap length is not less than the specified value.

4.2.3 number Stirrup spacing should comply with the design requirements and seismic requirements, hook angle of 135 °, hook the straight length of 10d.

4.2.4 reinforcing bar welding, no burn and ⅰ, ⅱ, ⅲ steel horizontal, uniform welding package. Bent butt welded joints of not more than 4 °, butt welded joint steel axis offset of less than 0.1d and less than 2rnm.

4.3 allowable deviation, as shown in table 4-12.

5 finished product protection

5.1 pillars after the reinforcement, no Stampede.

5.2 floor truss bar, after the negative moment reinforcement strap, are not allowed to walk above the stampede. Pouring concrete when the steel workers responsible for repairing, ensure the correctness of negative moment reinforcement.

5.3 binding reinforcement was forbidden to touch moving embedded parts and portal templates.

5.4 steel surfaces apply when used inside templates don't pollute bars.

5.5 installing the wire tubes, heating and plumbing pipes or other facility shall not be cut off and mobile bars.

6 quality problems to be noticed

6.1 check before pouring concrete reinforcement position is correct, vibrated concrete to prevent touch bar, position of dressing left immediately after you finish pouring concrete reinforcement to prevent column, wall reinforcement displacement.

6.2 design of steel frame size smaller than size: Stirrups should be prepared by endothelial size calculation.

Cast-frame reinforcement tolerance table 4-12

Project tolerance (mm) test method

1 Web length, width of ± 10 ' check

2 ± 20 feet of mesh size of three in a row, take the maximum value

3 frame width, height ± 5

4 frame length of ± 10

5 span ± 10

6 rows from the ± 5

7 fastening Stirrups, structural reinforcement pitch ± 20 feet three in a row, taking the maximum value

Beginning 8 steel bending displacement 20

Center line 5

Level height difference + 3-0 ' check

Beams and columns ± 5

Wall plate ± 3

6.3 core reinforcement of beam and column should be encrypted, familiar with the construction according to the requirements of drawings.

6.4 end Stirrup should bend 135 °, straight part length of 10d.

6.5 beam main bars into the bearing length should comply with the design requirements and bending rebar should be accurate.

6.6 plate bend reinforcement and negative moment reinforcement should be accurate, construction should not step down.

6.7 tie plate steel line with a ruler, lashing call was straightened to prevent sheet-beam is not straight, location.

6.8 tied it when hanging vertical stress reinforcement, lap tied part 3 buckle, Shun buckle tie clasp cannot be used in the same direction. Higher than 4m, scaffold for lashing, and take steps to fix bars prevent columns, steel skeletons not perpendicular to the wall.

6.9 on bars ingredients when you want to note that when end of welded joints, to avoid overlapping ranges to prevent binding joints with welding.

7 quality records

This standard shall meet the following quality records

7.1 steel quality certificate or test report form.

7.2 steel mechanical performance test report.

7.3 import steel chemical composition inspection report. Made in steel in the process of brittle fault, poor weldability and mechanical properties significantly abnormal, chemical composition inspection report.

7.4 bar hidden acceptance record.

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