Qingdao planting barReinforcement construction method
Snap line positioning
According to the position and quantity of the steel bars in the design drawing, stagger the position of the original structural steel bars and mark the position of the planting bars. Please check the circuit by the relevant department, and drill the hole only after it is qualified.
The drill bit diameter should be about 5mm larger than the steel bar diameter, the steel bar should be made of Shougang φ 25 steel bar, and the drill bit should be φ 30 alloy steel drill bit. The hole depth is 15d (375mm), and the actual drilling depth is 400mm; when drilling, the drill bit is always perpendicular to the cylinder.
Hole washing is the most important part of the planting bar construction, because a large amount of ash and slag will enter the planting bar after drilling, which directly affects the quality of the planting bar, so the impurities in the hole must be removed. The method is: cover the extension rod with a brush, extend into the bottom of the hole, repeatedly pump to remove the dust and slag, and then use compressed air to blow away the floating dust in the hole. After blowing, wipe the inner wall of the hole with absorbent cotton dipped in alcohol or acetone. But it cannot be scrubbed with water, because alcohol and acetone are easy to volatilize, and water is not easy to volatilize. This hole will not dry quickly after scrubbing with water. After the drilling is cleaned, the design unit and other related units should carry out inspection and acceptance, and the glue can be injected only after it is qualified.
Take a set of strong planting glue, put it in the sleeve, put it on the special manual syringe, slowly buckle the plate making machine, discharge the thinner glue from the platinum packaging port, discard it, and then extend the spiral mixing nozzle into the bottom of the hole. If the length is not enough, you can lengthen the plastic tube, then buckle the plate making machine, move the plate making machine hole once, and move the syringe backward once to expel the air in the hole. In order to make the glue in the hole full after planting the bar and prevent the glue from flowing out, the amount of glue injected into the hole can reach 80%. Reinforcement should be planted immediately after filling the hole with glue.
Before the glue injection, the beam bottom template has been installed to facilitate the positioning of the steel bars after the reinforcement is planted. Before planting the bars, the embedded steel parts should be repeatedly derusted with a wire brush, and then cleaned with alcohol or acetone. After injecting glue into the hole, immediately put the rust-removed steel bar into the hole, and then slowly screw it in one-way. Before the steel bar reaches the bottom of the hole, it is not allowed to reverse in the middle.
After the rebar is implanted, it should be positioned on the beam bottom template, and the rebar shall not be vibrated until the strong rebar glue is completely cured.
Cure at room temperature, and proceed to the next process after 50 hours.
Qingdao planting barBefore construction, a pull-out test should be carried out on site to determine whether the steel bars and planting glue meet the design requirements.
The method is: make a concrete specimen with the same strength level as the concrete member at the planting bar, implant three sets of steel bars according to the planting step, and perform a pull-out test after the steel bar glue is completely cured. When the force reaches the secondary steel bar yield strength (450N/mm2), the necking phenomenon occurs and the steel bar breaks.
During the test, the force applied by the dynamometer on the fixture should be FC≥fyk (FC: force applied by the dynamometer, N/mm2; FC: force applied by the dynamometer, N/mm2; FC: applied by the dynamometer Force, N/mm2; FC: force applied by dynamometer, n/mm2; FC: force applied by dynamometer, N/mm2; Fyk: yield strength of steel bar, N/mm2)
The test results show that the strength of the glue is greater than the yield strength of the steel bar. The failure of the glue is the yield failure of the steel bar, not the bonding failure of the glue, indicating that both the steel bar and the glue are qualified.
The non-destructive pull-out test is used to detect the quality of the steel bars after planting, and the number of inspections is 10% of the total number of steel bars.
In the test, the force applied by the dynamometer should be less than the yield strength of the steel bar and greater than the design anchoring force of the planting bar provided by the design department. The formula is: FM
After passing the test, the next process can be carried out.