Enlarging section method

Engineering survey

Because the strength of the 5-storey shear wall (column) of No. 1 building is not up to standard, it should be strengthened after checking by the original designer. Reinforcement scheme: strengthening by means of increasing section method (post installed anchoring).

Reinforcement construction plan

Interface treatment

Use the flower hammer and the wheel machine to coat the original structure; if necessary, chisel until it is dense.

1. Hairing: 1.5kg-2.5kg pointed stone hammer should be used to chisel pits on the concrete bonding surface, forming a point depth of about 3mm, points of 600 points / ~ 800 points / / ~ evenly distributed chisel can also be chiseled into a point depth of 4mm ~ 5mm, spacing of about 30mm plum-shaped distribution.

2. Grinding wheel: It is suitable to adopt coarse grinding wheel with output power not less than 340W, and punch out transverse lines perpendicular to the axis of the component, with grain depth of 3mm~4mm and spacing of about 50mm on the concrete bonding surface.

3. Manual grooving: It is advisable to use sharp, sharp chiseling, in the solid concrete bonding surface chiseling direction perpendicular to the axis of the member, groove depth of about 6 mm, spacing of about 100 mm ~ 150 mm of transverse groove.

After the above processing, the loose aggregate, sand and gravel, scum and dust on the concrete surface of the original component are removed by using steel wire brush and other tools, and the concrete surface is washed clean with clean pressure water.

Chemical rebar anchoring

1. Use special punching machine to punch holes so that the steel bar to be implanted can be normal implantation, drilling depth is not less than the design and specifications required depth.

2. After drilling, the dust in the hole and interface must be removed by brush, and then the dust is blown out by blower to clear the hole, so as to ensure the bonding of adhesive and concrete.

3. When injecting glue into boreholes, the air in boreholes should be excluded. In order to achieve this goal, the mixing nozzle should be inserted into the bottom of the borehole as far as possible. The injection depth should be 2/3 of the hole depth and the steel bar should be extruded slightly.

4. Reinforcement: It is necessary to use non-corrosive steel bars embedded in drilling holes, and then slowly rotate the steel bars in the holes to facilitate adhesion between glue and the hole wall, in which glue is injected into the gap between the bars and the holes. Two rows of scaffolding are erected at the front of the reinforcement to temporarily fix the reinforcement. The reinforcement after implantation should leave enough time for the adhesive to solidify.

5. Welding of steel bar: single side welding is larger than 10D, double side welding is larger than 5D. The weld is full and the height is higher than 5mm.

6. Inspection of steel bar: the raw material of steel bar must be checked and qualified; the planting bar must be qualified for pull-out test.

Installing new reinforcement

1. According to the blueprint, new reinforcement bar, bar and stirrups should be added.

2. When the new reinforced bar is connected with the original reinforced bar, it is welded with short bars. The diameter of the short bars is not less than 20 mm, the length is not less than five times of the diameter, and the middle distance of the short bars is not more than 500 mm.

3. When the side of the tensile section is strengthened, the U hoop should be installed. The U-shaped hoop shall be welded on the original hoop, the length of one-side weld shall be ten times the diameter of hoop, and the length of double-side weld shall be five times the diameter of hoop.

Install the template

1. First find the center line, then look for the sideline.

2. Set the side mould vertically on the side line according to the size of the side line, and ensure the verticality and elevation of the side mould without any error. Stable with diagonal braces and supporting nails to ensure the stability and rigidity of the side pressure.

3. After installing the template, check the center line and check whether the center line is correct. Then check the axis, whether the geometric size and elevation are up to the standard, then remove the debris.

Pouring fine stone concrete

1. Before pouring concrete, the template and interface should be fully moistened and there should be no water accumulation at the bottom.

2. The grouting time should be shortened as much as possible. Pouring must be poured while vibrating to ensure the compactness of concrete, to avoid defects such as holes, faults, honeycombs, hemp surface after demolition.

Curing

1. Concrete should be immediately covered with wet grass or rock wool quilt within 60 minutes after final solidification and keep moist.

3, 24-36 hours after grouting can not be vibrated to avoid damaging the unconsolidated grout layer.